Oregon codes are available for viewing online at: Oregon.gov/bcd. CCP-PW29 (Rev.
11/2111/21)
CLACKAMAS COUNTY DEPARTMENT OF TRANSPORTATION AND DEVELOPMENT
BUILDING CODES DIVISION
2021 EDITION OF THE OREGON RESIDENTIAL SPECIALTY CODE (BASED ON THE 2018 IRC)
SUMMARY OF RESIDENTIAL STRUCTURAL AND MECHANICAL CODE REQUIREMENTS
Oregon codes are available for viewing online at: Oregon.gov/bcd.
This checklist and all approved construction documents must be kept on the job site at all times while work is in progress. All
work must be installed in accordance with the approved construction documents, and any changes shall be resubmitted for
approval as an amended set of construction documents, in accordance with Section R106.
Refer to the building permit card and Section R109 for required inspections.
Certificate of Occupancy (Section R110)
Residential Certificate of Occupancy. Prior to occupancy of a new residential dwelling or townhouse, the building
official must issue a certificate of occupancy in the form and format established by the division. OAR 918-480-0140
Definitions (Section R202)
BUILDING HEIGHT. The vertical distance from grade plane to the average height of the highest roof surface.
GRADE PLANE. A reference plane representing the average of the finished ground level adjoining the building at all
exterior walls. Where the finished ground level slopes away from the exterior walls, the reference plans shall be
established by the lowest points within the area between the building and the lot line or, where the lot line is more than
6 feet from the building: Between the structure and a point 6 feet from the building.
HABITABLE SPACE. A space in a building for living, sleeping, eating or cooking. Bathrooms, toilet rooms, closets, halls,
storage or utility spaces and similar areas are not considered habitable spaces.
LOT LINE. A line dividing one lot from another, or from a street or any public place.
Minimum Design Criteria (Section R301)
Design Wind Speeds: 98mph V-basic (76mph V
asd
), 120mph V-basic (93mph V
asd
) if located within a special wind region
as determined using the ATC Hazards By Location webtool (for sunrooms, refer to R301.2.1.1).
Wind Exposure Category: To be determined in accordance with R301.2.1.3 (Exposure C may be used as a default).
Seismic Category: Either C, D
0,
of D
1
depending on location, as determined using the ATC Hazards By Location webtool
and Table R301.2.2.1.1.
Ground Snow Load: As determined using the SEAO Snow Load webtool (See “Map Usage Notes” for local elevation
adjustment factors. Project site coordinates may be found using Google Maps).
The ATC Hazards By Location webtool is available online at: https://hazards.atcouncil.org/#/
o Instructions for determining seismic design criteria are available at:
https://www.oregon.gov/bcd/codes-stand/Documents/2021orsc-sdc-howto.pdf
o Instructions for determining whether a location is located within a special wind region are available
at: https://www.oregon.gov/bcd/codes-stand/Documents/2021orsc-special-wind-region-howto.pdf
The SEAO Snow Load webtool is available online at: http://snowload.seao.org/lookup.html#
o Instructions for determining ground snow load are available at: https://www.oregon.gov/bcd/codes-
stand/Documents/2021orsc-snowload-map-howto.pdf
Site Address
1. Address identification. The address identification shall be legible and placed in a position that is visible from the street
or road fronting the property, with characters which contrast with their background. Section R319.1
Light, Ventilation, and Heat
2. Stairway illumination: Interior stairways shall be provided with an artificial light source to illuminate the stair landings
and treads, with wall switches at each floor level where there are 6 or more risers. Exterior stairways shall be provided
with an artificial light source located at the top landing (located at the bottom landing for stairways accessing basements
from outdoor grade level). Sections R303.7 and R303.8
CLACKAMAS COUNTY – 2021 RESIDENTIAL CODE SUMMARY
Oregon codes are available for viewing online at: Oregon.gov/bcd. CCP-PW29 (Rev. 11/21)
3. Habitable room glazing. All habitable rooms shall be provided with aggregate glazing area of not less than 8 percent of
the floor area of such rooms. Natural ventilation shall be through windows, doors, louvers or other approved openings
to the outdoor air. The minimum openable area to the outdoors shall be 4 percent of the floor area being ventilated.
Section R303.1
Exceptions:
1. The glazing areas need not be openable where the opening is not required by Section R310 and a whole-
house mechanical ventilation system is installed in accordance with M1505.
2. The glazed areas need not be provided in rooms where exception #1 above is satisfied and artificial light is
provided capable of producing an average illumination of 6 foot-candles (65 lux) over the area of the room at
a height of 30 inches above the floor level.
3. Use of sunroom and patio covers, as defined in Section R202, shall be permitted for natural ventilation if in
excess of 40 percent of the exterior sunroom walls are open, or are enclosed only by insect screening.
4. Rooms with bathing or spa facilities. Any room with a bathtub, shower or spa facility shall be provided with mechanical
ventilation designed and installed in accordance with Section M1505.5. Section R303.3.1
Bathrooms without bathing or spa facilities. Water closet compartments or toilet rooms without bathtub,
shower or spa facilities shall be provided with aggregate glazing area of not less than 3 square feet (0.3 m2),
one-half of which must be openable. Section R303.3.2.
Exception: The glazed areas shall not be required where artificial light and a mechanical ventilation
system is provided. The minimum ventilation rate shall be in accordance with Table M1505.5.
Safety glazing is required in walls, enclosures, or fences containing or facing hot tubs, spas, whirlpools,
saunas, steam rooms, bathtubs, showers, and swimming pools where the bottom exposed edge of the
glazing is less than 60 inches measured vertically above any standing or walking surface (applies to each pane
in single or multiple glazing). Section R308.4.5
Exception: Glazing that is more than 60 inches, measure horizontally and in a straight line, from the
water’s edge of a bathtub, hot tub, spa, whirlpool, or swimming pool OR from the edge of a shower,
sauna, or steam room.
5. Whole-house mechanical ventilation is required for all new dwelling units, and shall be designed to provide outdoor
air at a minimum rate based on the dwelling’s floor area and number of bedrooms in accordance with M1505.4. Sections
R303.4 and M1505.4
6. Required heating. Every dwelling unit shall be provided with heating facilities capable of maintaining a minimum room
temperature of 68
0
F at a point 3 feet above the floor and 2 feet from exterior walls in all habitable rooms at the design
temperature. The installation of one or more portable space heaters shall not be used to achieve compliance with this
section. Section R303.10
Conditioned air ducts shall be located fully within the building envelope or buried within R-8 insulation (with
gaps and voids between ductwork and ceilings filled with insulation, a minimum of R-19 above ducts where
located in unconditioned attics, and depth marker flags installed every 10 feet) in accordance with N1105.
Exceptions:
1. Exhaust and intake ductwork.
2. The replacement or addition of a furnace, air conditioner, or heat pump shall not require existing
ducts to be insulated to current requirements.
3. Up to 5% of a system’s ductwork may be located outside of the thermal envelope.
Minimum Areas, Dimensions and Ceiling Height
7. Minimum dimensions and area. Habitable rooms shall be no less than 7 feet in any horizontal dimension, and shall
have a floor area of not less than 70 square feet (not including areas with sloped ceilings less than 5 feet, or furred
ceiling areas less than 7 feet, in height). Section R304
Exception: Kitchens.
8. Ceiling height. Habitable space, hallways, and portions of basements containing these spaces shall have a ceiling height
of not less than 7 feet. Bathrooms, toilet rooms and laundry rooms shall have a ceiling height of not less than 6 feet 8
inches. Section R305
Exceptions:
1. For rooms with sloped ceilings, the required floor area of the room shall have a ceiling height of not less
than 5 feet and not less than 50 percent of the required floor area shall have a ceiling height of not less
than 7 feet.
2. Not more than 75 percent of the floor area of a bathroom or toilet room is permitted to have a sloped
ceiling less than 6 feet 8 inches in height, provided an area of 21 inches by 24 inches in front of toilets and
lavatories have a minimum of 6 feet, 4 inches in height. An area of 24 inches by 30 inches in front of and
inside a tub shower shall have a minimum of 6 feet, 4 inches in height, measured from the standing surface
of the fixture.
3. Beams, girders, ducts or other obstructions in basements containing habitable space shall be permitted to
project to within 6 feet 4 inches of the finished floor.
4. Beams and girders spaced not less than 4 feet on center may project not more than 6 inches below the
required ceiling height.
CLACKAMAS COUNTY – 2021 RESIDENTIAL CODE SUMMARY
Oregon codes are available for viewing online at: Oregon.gov/bcd. CCP-PW29 (Rev. 11/21)
5. Conversion of existing nonhabitable space, such as a basement or attic, to habitable space, shall provide a
minimum 6 feet 8 inches ceiling height for flat ceilings or for the portion required for exception #1 in this
section.
9. Hallway. The minimum width of a hallway shall be not less than 3 feet. Section R311.6
10. Bathtub and shower spaces. Fixtures shall be spaced as shown in Figure R307.1, and in accordance with the
requirements of the Plumbing Code (see OPSC Section 408.6).
11. Mezzanines. The clear height above and below mezzanine floors shall be not less than 7 feet. The aggregate area of 1
or more mezzanines shall not be greater than 1/3 of the floor area of the room in which they are located (not including
enclosed portions of the room). Mezzanines shall be open and unobstructed to the room in which they are located
except for walls not more than 3 feet in height, columns and posts. Section R325.
Exception to area limitations: The aggregate area of a mezzanine located within a dwelling unit equipped with
an approved fire sprinkler system shall not be greater than 1/2 of the floor area of the room, provided that the
following requirements are met:
1. Except for enclosed closets and bathrooms, the mezzanine is open to the room in which it is located.
2. The opening to the room is unobstructed except for walls not more than 42 inches in height, columns
and posts.
3. The exceptions to openness requirements are not applied.
Exceptions to openness requirements:
1. Portions of mezzanines are not required to be open to the room in which they are located, provided
that the aggregate floor area of the enclosed space is not greater than 10% of the mezzanine area.
2. In buildings that are not more than 2 stories above grade plane and equipped throughout with an
approved automatic sprinkler system, a mezzanine shall not be required to be open to the room in
which it is located.
12. Habitable attics. A habitable attic shall be considered a story above grade plane, and shall comply with dimension, area,
and height requirements for habitable spaces per Sections R304 and R305. Section R326.
Exception: A habitable attic shall not be considered a story above grade plane where all of the following apply:
1. The aggregate area of the habitable space is not greater than 1/3 of the floor area of the story below
or, where located in dwelling units equipped throughout with an automatic fire sprinkler system in
accordance with NFPA 13D, the habitable space is not greater than 1/2 of the floor area of the story
below.
2. The occupiable space is enclosed by the roof assembly above; knee walls, if applicable, on the side;
and the floor-ceiling assembly below.
3. The floor of the habitable attic does not extend beyond the exterior walls of the story below.
4. Where the habitable attic is located above a 3
rd
story, the dwelling unit or townhouse shall be
equipped throughout with an automatic fire sprinkler system in accordance with NFPA 13D.
Windows and Doors
13. Emergency Escape and Rescue Openings. Basements, habitable attics, and every sleeping room shall have at least one
openable emergency escape and rescue opening. Where basements contain one or more sleeping rooms, openings
shall be required in each sleeping room. Where a door serves as the emergency escape and rescue opening, the door
shall be side-hinged or a slider. The net clear opening dimensions required by this section shall be obtained by the
normal operation of the emergency escape and rescue opening from the inside. Openings with a finished sill or
threshold height below the adjacent ground elevation shall be provided with a well in accordance with Section R310.2.3
or R310.3.2. Openings shall open directly into a public way, or to a yard or court that opens to a public way. Openings
located beneath decks, porches, and similar projections shall be allowed to fully open to a path not less than 35 inches
in height to a yard or court. Openings located above a roof surface shall be provided with an unobstructed path, not
less than 3 feet in width, from the vertical plans of the opening to the nearest edge of the lower roof, as practicable.
Section R310
Exceptions:
1. Storm shelters and basements used only to house mechanical equipment and not exceeding total
floor area of 200 square feet.
2. Where the dwelling or townhouse is equipped with an automatic sprinkler system installed in
accordance with NFPA 13D, sleeping rooms in basements shall not be required to have emergency
escape and rescue openings provided that the basement has one of the following:
a. One means of egress complying with Section R311 and one emergency escape and rescue
opening.
b. Two means of egress complying with Section R311.
3. Replacement windows may be exempt from sill height and minimum opening area requirements
where all of the following conditions apply:
a. The replacement window is the largest standard window that will fit within the existing frame
or rough opening, and is the same operating style as the existing window (or a style which
provides an equal or greater opening area than the existing window).
b. The replacement window is not part of a change in occupancy or use.
4. Emergency escape and rescue openings are not required in new basements which are part of an
addition where the following conditions apply:
a. The new basement contains a sleeping room with an emergency escape and rescue opening.
CLACKAMAS COUNTY – 2021 RESIDENTIAL CODE SUMMARY
Oregon codes are available for viewing online at: Oregon.gov/bcd. CCP-PW29 (Rev. 11/21)
b. The new basement is accessed from an existing basement with an emergency escape and
rescue opening.
5. An emergency escape and rescue opening is not required in existing basements undergoing
alterations or repairs, unless a new sleeping room is created within the existing basement.
Minimum opening area. All emergency escape and rescue openings shall have a minimum net clear opening of 5.7
square feet. Section R310.2.1
Exception: Grade floor openings (bottom of clear opening not more than 44 inches above or below finished
ground level) shall have a minimum net clear opening of 5 square feet.
Minimum opening dimensions are 24 inches wide and 20 inches tall (net clear), and the minimum net clear width
is 20 inches. Section R310.2.1
Maximum sill height shall not exceed 44 inches in height, measured from top of finished floor to the bottom edge
of the clear opening. Where the sill height is below grade, it shall be provided with a window well in accordance
with Section R310.2.3. Section R310.2.2.
Operational constraints. Emergency escape and rescue openings shall be operational from the inside of the room
without the use of keys, tools or special knowledge. Section R310.1.1
Where located above roof surfaces, emergency escape and rescue openings shall be provided with an
unobstructed path, not less than 36 inches in width, from the vertical plane of the opening to the nearest edge of
the lowest roof, as practicable. Section R310.2.5
14. Window Fall Protection. In dwelling units, where the top of the sill of an operable window opening is located less than
24 inches above the finished floor and greater than 72 inches above the finished grade or flat surface not less than 36
in width below on the exterior of the building, the operable window shall not allow a 4 inch sphere to pass through in
its largest opened position, or be provided either with window fall protection devices or window opening control devices
that comply with ASTM F2090. Such devices may not reduce the minimum net clear opening area for required
emergency escape openings as required by Section R310.2.1. Section R312.2
15. Safety glazing is required in all hazardous locations, such as windows where the nearest vertical edge is within 24 inches
of a door, at sliding glass doors, French doors, tub/shower enclosures, glazing adjacent to walking surfaces (such as
stairways, landings and ramps), and glazing in wet locations (such as bathing rooms, spas, saunas, steam rooms, and
swimming pool areas) where exposed glazing is located within 60 inches measured horizontally from the water’s edge
and is less than 60 inches measured vertically from a standing or walking surface. For specific requirements, refer to
Section R308.4. Section R308
16. Egress Door. Not less than one side-hinged egress door, with a minimum clear width of 32 inches and a minimum height
of 78 inches, shall be provided for each dwelling unit or accessory structure containing habitable space. A continuous,
unobstructed path from all portions of the dwelling or habitable space shall be provided to the egress door without
requiring travel through a garage or carport. Egress doors shall open directly to a public way, or a yard or court that
opens to a public way, and shall be readily openable from inside without the use of a key or special knowledge or effort.
Sections R311.1 and R311.2
17. Landings at exterior doors: There shall be a floor or landing on each side of each exterior door. The width of each
landing shall not be less than the door served. Every landing shall have a minimum dimension of 36 inches measured in
the direction of travel. The floor or landing at the required egress door shall not be more than 1.5 inches lower than
the top of the threshold, and where such landings are not at grade they shall be provided with access to grade by means
of a ramp in accordance with Section R311.8 or a stairway in accordance with R311.7. For other doors, the landing shall
not be more than 8” below the top of the door threshold and provided the door does not swing over the landing. The
landing shall be permitted to have a slope not to exceed 0.25 units vertical in 12 units horizontal (2-percent). Section
R311.3
Exception: Exterior balconies less than 60 square feet in area and only accessed from a door are
permitted to have a landing less than 36 inches measured in the direction of travel.
Attachment. Exterior landings, decks, balconies, stairs, and similar facilities shall be positively anchored to the
primary structure to resist both vertical and lateral forces or shall be designed to be self-supporting. Such
attachment shall not be accomplished by the use of toenails or nails subject to withdrawal. Sections R311.5
and R507.
Stairways, Ladders, and Ramps
18. Stairways shall be not less than 36 inches in clear width at all points above the permitted handrail height and below the
required headroom height. The clear width of stairways at and below the handrail height, including treads and landings,
shall be not less than 31-1/2 inches (27 inches where a handrail is installed on both sides). Section R311.7.1
Exception: Where a floor is served by more than one stairway, stairways other than the first stairway
may have a clear width of not less than 30 inches. Any handrail may encroach a maximum of 4-1/2
inches into the clear width. Section R311.7.1
Headroom. The minimum headroom in all parts of the stairway shall not be less than 6 feet 8 inches measured
vertically from the sloped plane adjoining the tread nosing or from the floor surface of the landing platform.
Section R311.7.2
Exception: Where the nosings of treads at the side of a flight extend under the edge of a floor opening
through which the stair passes, the floor opening shall be allowed to project horizontally into the
CLACKAMAS COUNTY – 2021 RESIDENTIAL CODE SUMMARY
Oregon codes are available for viewing online at: Oregon.gov/bcd. CCP-PW29 (Rev. 11/21)
required headroom not more than 4-3/4 inches.
Vertical rise. A flight of stairs shall not have a vertical rise larger than 151 inches between floor levels or
landings. Section R311.7.3
Risers. The maximum riser height shall be 8 inches and shall be measured vertically between the leading edges
of the adjacent treads. The greatest riser height within any flight of stairs shall not exceed the smallest by more
than 3/8 inch. Risers shall be vertical or sloped from the underside of the leading edge of the tread above at
an angle not more than 30 degrees from the vertical. Open risers are permitted, provided that the opening
between treads does not permit the passage of a 4-inch-diameter sphere. Section R311.7.5.1
Treads. The minimum tread depth shall be 9 inches. The tread depth shall be measured horizontally between
the vertical planes of the foremost projection of adjacent treads and at a right angle to the tread’s leading
edge. The walking surface of treads and landings of a stairway shall be sloped no steeper than one unit vertical
in 48 units horizontal (2-percent slope). The greatest tread depth within any flight of stairs shall not exceed the
smallest by more than 3/8 inch. Section R311.7.5.2
Nosings. Treads, landings, and floors of stairways shall have a radius of curvature at the nosing not greater
than 9/16 inch, or a bevel not greater than ½ inch. A nosing projection not less than 3/4 inch, and not more
than 1-1/4 inches, shall be provided on stairways. The greatest nosing projection shall not exceed the smallest
nosing projection by more than 3/8 inch within a stairway.
Exception: A nosing is not required where the tread depth is a minimum of 10 inches.
Slope. Where the top or bottom riser adjoins a sloping walk, garage floor or driveway, the top or bottom riser
may be reduced along the slope, with a variation in height not exceeding 3 inches, in every 3 feet of walk or
stairway width. Section R311.7.5.5
Landings. There shall be a floor or landing at the top and bottom of each stairway. The minimum stair landing
width, perpendicular to the direction of travel, shall be no less than the width of the flight served. Landing of
shapes other than square or rectangular shall be permitted provided the depth at the walk line and the total
area is not less than that of a quarter circle with a radius equal to the required landing width. Where the
stairway has a straight run the minimum depth in the direction of travel shall not be less than 36”. Section
R311.7.5
Exception: A floor or landing is not required at the top of an interior flight of stairs, provided a door
does not swing over the stairs.
Spiral and winding stairs. The clear width shall be not less than 26 inches and the walkline radius shall be not
greater than 24-1/2 inches. Each tread shall be identical, with a depth not less than 6-3/4 inches at the walkline
and a rise not more than 9-1/2 inches. Headroom shall be not less than 6 feet 6 inches. Section R311.7.10.1
Bulkhead enclosure stairways. Where providing access to a basement from outside grade through an
approved bulkhead enclosure which is not part of a required egress, and the height from basement floor to
adjacent exterior grade is not more than 8 feet, requirements for stairways and door landings do not apply.
Section R311.7.10.2
19. Ladders. Ship’s ladders (with slopes between 50 and 70 degrees) are permitted where a means of egress are not
required, or where a compliant stairway or ramp serves the same space at each adjoining level, with a minimum clear
width of 20 inches, minimum tread depth of 5 inches, tread depth plus nosing projection is not less than 8-1.2 inches,
and maximum riser height of 9-1/2 inches. Compliant handrails shall be provided on both sides, with a uniform height
not exceeding 34 inches. Section R311.7.12
20. Ramps serving the required egress door shall have a maximum slope of 1:12 (8.3 percent slope). All other ramps shall
have a maximum slope of 1:8. Section R311.8
Exceptions: Where it is technically infeasible to comply because of site constraints, a ramp serving a
required egress door may have a maximum slope of 1:8.
Landings. There shall be a floor or landing at the top and bottom of each ramp, where doors open onto ramps,
and where ramps change direction. The width of the landing perpendicular to the ramp slope shell be not less
than 36 inches. Section R311.8.2
Applicability. Ramps not within or directly serving a regulated building, patio, porch, or deck are not required
to comply with this section.
Accessibility Note: Dwelling units required to be accessible by ORS 447.231 shall comply with Chapter 11 of
the Oregon Structural Specialty Code as applicable. Section R320
Handrails and Guards
21. Handrails shall be provided on at least one side of each flight of stairs with four or more risers (for winders, the handrail
shall be located on the side where the treads are narrower), and at each ramp exceeding a slope of 1:12. Sections
R311.7.8 and R311.8.3
Height, measured vertically from the sloped plane adjoining the tread nosing, or finish surface of ramp slope,
shall be not less than 30 inches and not more than 38 inches. Sections R311.7.8.1 and R311.8.3.1
Exceptions (for stairs only):
CLACKAMAS COUNTY – 2021 RESIDENTIAL CODE SUMMARY
Oregon codes are available for viewing online at: Oregon.gov/bcd. CCP-PW29 (Rev. 11/21)
1. The use of a volute, turnout or starting easing shall be allowed over the lowest tread.
2. Where handrail fittings or bendings are used to provide continuous transition between flights,
transitions at winder treads, the transition from handrail to guard, or used at the start of a flight, the
handrail height at the fittings or bendings shall be permitted to exceed 38 inches.
3. When a handrail is incorporated as the top of a guard, the minimum height shall be not less than 34
inches and not more than 38 inches as measured vertically from a line connecting the leading edges
of the treads.
Projection. Handrails shall not project more than 4-1/2 inches on either side of a stairway.
Exception. Where nosings of landings, floors or passing flights project into the stairway reducing the
clearance at passing handrails, handrails shall project not more than 6-1/2 inches into the stairway,
provided that the stair width and handrail clearance are not reduced to less than that required.
Continuity. Handrails for stairways shall be continuous for the full length of the flight, from a point directly
above the top riser of the flight to a point directly above lowest riser of the flight. Handrails for ramps shall be
continuous for the full length of the ramp. Handrail ends shall be returned or shall terminate in newel posts or
safety terminals. Handrails adjacent to a wall shall have a space of not less than 1-1/2 inch between the wall
and the handrail. Sections R311.7.8.2 and R311.8.3.3
Exceptions:
1. Handrails shall be permitted to be interrupted by a newel post at a turn.
2. The use of a volute, turnout, starting easing or starting newel shall be allowed over the lowest
stair tread.
Grip size. All required handrails shall be of one of the following types or provide equivalent graspability.
Sections R311.7.8.3 and R311.8.3.2.
Type I. Handrails with a circular cross section shall have an outside diameter of at least 1¼ inches and
not greater than 2 inches. If the handrail is not circular it shall have a perimeter dimension of at least
4 inches and not greater than 6-1/4 inches with a maximum cross section of dimension of 2¼ inches.
Type II. Handrails with a perimeter greater than 6¼ inches shall provide a graspable finger recess area
on both sides of the profile. The finger recess shall begin within a distance of ¾ inch measured
vertically from the tallest portion of the profile and achieve a depth of at least 5/16 inch with 7/8 inch
below the widest portion of the profile. The minimum width of the handrail above the recess shall be
1¼ inches to a maximum of 2¾ inches. Edges shall have a minimum radius of 0.01 inches.
22. Guards shall be located along open-sided walking surfaces, including stairs, ramps and landings, for the portions which
are located more than 30 inches measured vertically to the floor or grade below at any point within 36 inches
horizontally to the edge of the open side. Guards shall be designed and constructed to resist live loads per Table R301.5.
Insect screening shall not be considered as a guard. Sections R301.5 and R312.1.1
Height. Required guards shall be not less than 36 inches in height as measured vertically above the adjacent
walking surface or a line connecting the nosings. Section R312.1.2.
Exceptions:
1. Guards on the open side of stairs shall have a height of not less than 34 inches measured vertically
from a line connecting the leading edges of the treads.
2. Where the top of a guard serves as a handrail on the open sides of stairs, the top of the guard
shall be not less than 34 inches and not more than 38 inches as measured vertically from a line
connecting the nosings.
Guard opening limitations. Required guards shall have intermediate rails or ornamental closures which do not
allow passage of a sphere 4 inches in diameter. Section R312.1.3
Exceptions:
1. The triangular openings formed by the riser, tread and bottom rail of a guard at the open side of
a stairway are permitted to be of such size that a sphere 6 inches cannot pass through.
2. Openings for required guardrails on the sides of stairs shall not allow passage of a sphere 5 inches
or more in diameter to pass through. Opening limitations for required guardrails on open sides of
stairways are applicable above the second riser of the stair.
Alarms
23. Smoke and CO alarms shall comply with NFPA 72, shall be listed in accordance with UL 217, and shall be provided within
new dwelling units. Where alterations, repairs, or additions requiring a permit occur, or where one or more sleeping
rooms are added or created in existing dwellings, the individual dwelling unit shall be equipped with smoke alarms
located as required for new dwellings. Section R314
Exceptions:
1. Work involving the exterior surfaces of dwellings, such as the replacement of roofing or siding,
the addition or replacement of windows or doors, or the addition of a porch or deck, are exempt
from the requirements of this section.
2. Installation, alteration or repairs of plumbing or mechanical systems are exempt from the
requirements of this section.
Locations. Smoke alarms shall be installed in the following locations per Section R314.3:
In each sleeping rooms.
CLACKAMAS COUNTY – 2021 RESIDENTIAL CODE SUMMARY
Oregon codes are available for viewing online at: Oregon.gov/bcd. CCP-PW29 (Rev. 11/21)
Outside of each separate sleeping area, within 21 feet of any door to a sleeping room, measured along the
path of travel.
On each additional story of the dwelling, including basements but not including crawl spaces and
uninhabitable attics. In dwellings or dwelling units with split levels and without an intervening door
between the adjacent levels, a smoke alarm installed on the upper level shall suffice for the adjacent lower
level provided that the lower level is less than one full story below the upper level.
Smoke alarms shall be installed not less than 3 feet horizontally from a door or opening of a bathroom that
contains a bathtub or shower unless this would prevent placement of a smoke alarm required by this
section.
Refer to NFPA 72, Section 29.5 for additional requirements.
Installation near cooking appliances. Per Section R314.3.1, smoke alarms shall not be installed in the following
locations unless this would prevent placement of a smoke alarm in a location required by Section R314.3:
Ionization smoke alarms shall not be installed less than 20 feet horizontally from a permanently installed
cooking appliance.
Ionization smoke alarms with an alarm-silencing switch shall not be installed less than 10 feet horizontally
from a permanently installed cooking appliance.
Photoelectric smoke alarms shall not be installed less than 6 feet horizontally from a permanently installed
cooking appliance.
Interconnection. Where more than one smoke alarm is required to be installed within an individual dwelling
unit in accordance with Section R314.3, the alarm devices shall be interconnected in such a manner that the
actuation if one alarm will activate all of the alarms in the individual dwelling unit. Physical interconnection of
smoke alarms shall not be required where listed wireless alarms are installed and all alarms sound upon
activation of one alarm.
Exception: Hardwired interconnection in existing areas shall not be required where alterations or repairs
do not result in the removal of interior wall or ceiling finishes exposing the structure.
Power source. Smoke alarms shall receive their primary power from the building wiring where such wiring is
served from a commercial source and, where primary power is interrupted, shall receive power from a battery.
Wiring shall be permanent and without a disconnecting switch other than those required for overcurrent
protection.
Exceptions:
1. Alarms shall be permitted to be battery operated where installed in buildings without power.
2. Smoke alarms for alterations, repairs, and additions shall be permitted to be battery powered.
Fire Alarm Systems may be used in lieu of smoke alarm systems in accordance with Section R314.7
Carbon monoxide alarms shall be be listed in accordance with UL 2034, and shall be provided within new dwelling units.
Where a new carbon monoxide source is introduced or work requiring a structural permit occurs in existing dwellings,
carbon monoxide alarms shall be provided as required for new dwellings. Sections R315.1 and R315.2
Exception: Work involving the exterior surfaces of dwellings, such as the replacement of roofing or
siding, the addition or replacement of windows or doors, or the addition of a porch or deck, are
exempt from the requirements of this section.
Location. Carbon monoxide alarms shall be located in each bedroom or within 15 feet of each sleeping room
door. Sleeping rooms on separate floor levels in a structure consisting of two or more stories shall have
separate carbon monoxide alarms serving each story. Where a fuel-burning appliance is located within a
sleeping room or its attached bathroom, a carbon monoxide alarm shall be installed within the sleeping room.
Section R315.3
Interconnection. Where more than one carbon monoxide alarm is required within an individual dwelling unit,
they shall be interconnected in such a manner that the actuation if one alarm will activate all of the alarms in
the individual dwelling unit. Physical interconnection of smoke alarms shall not be required where listed
wireless alarms are installed and all alarms sound upon activation of one alarm.
Exception: Interconnection is existing areas is not required where alterations or repairs do not result
in the removal of interior wall or ceiling finishes exposing the structure.
Power Source. Carbon monoxide alarms shall receive their primary power from the building wiring where such
wiring is served from a commercial source and, where primary power is interrupted, shall receive power from
a battery. Wiring shall be permanent and without a disconnecting switch other than those required for
overcurrent protection.
Exception: Battery operation is permitted in buildings without power, and for alterations, repairs, and
additions.
Combination smoke and carbon monoxide alarms may be used in lieu of separate smoke and carbon monoxide alarms,
and shall be listed in accordance with UL 2034 and UL 217. Interconnection and hard-wiring of combination
smoke/carbon monoxide alarms in existing areas shall not be required where the alterations or repairs do not result in
the removal of interior wall or ceiling finishes exposing the structure.
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Fire Resistant Construction
24. Fireblocking shall be provided to cut off all concealed draft openings (both vertical and horizontal) and to form an
effective fire barrier between stories, and between a top story and the roof space. Wood fireblocking shall be 2 inches
nominal thickness, two thicknesses of 1 inch nominal lumber with broken lap joints, 23/32 inch wood structural panels
with joints backed by the same, 3/4 inch particleboard with joints backed by the same, 1/2” gypsum board, 1/4” cement-
based millboard, other approved materials securely fastened in place, or cellulose insulation installed as tested in
accordance with ASTM E119 or UL 263 for the specific application. Mineral or glass fiber batts of blankets may be used
for horizontal fireblocking at 10 foot spacing in walls constructed of parallel or staggered studs. Where unfaced
fiberglass is used as fireblocking, it must fill the entire cross section of the wall cavity to a minimum height of 16 inches.
Sections R302.11 and R602.8
Fireblocking shall be provided in wood-frame construction in the following locations:
1. In concealed spaces of stud walls and partitions, including furred spaces, at the ceiling and floor level and at 10
foot intervals both vertical and horizontal. Batts or blankets of mineral wool or glass fiber or other approved
non-rigid materials shall be allowed as fireblocking in walls constructed using parallel rows of studs or
staggered studs.
2. At all interconnections between concealed vertical and horizontal spaces such as occur at soffits, drop ceilings,
cove ceilings.
3. In concealed spaces between stair stringers at the top and bottom of the run. Enclosed spaces under stairs
shall comply with Section R311.2.2.
4. At openings around vents, pipes, ducts, cables and wires at ceiling and floor level, with an approved material
to resist the free passage of flame and products of combustion.
5. For the fireblocking of chimneys, refer to R1003.19. For fireplaces, refer to Sections R302.11, R602.8, and
R1001.12.
6. Fireblocking of cornices of a two-family dwelling is required at the line of dwelling unit separation,
25. Draftstopping required. When there is usable space both above and below the concealed space of a floor/ceiling
assembly, draftstops shall be installed so that the area of the concealed space does not exceed 1,000 square feet.
Draftstopping shall divide the concealed space into approximately equal areas. Where the assembly is enclosed by a
floor membrane above and a ceiling membrane below draftstopping shall be provided in floor/ceiling assemblies under
the following circumstances:
1. Ceiling is suspended under the floor framing.
2. Floor framing is constructed of truss-type open-web or perforated members. Section R302.12
26. Draftstopping materials shall be 1/2-inch gypsum board, 3/8-inch wood structural panels, and 3/8” Type 2-M-W
particleboard or other approved material adequately supported. Draftstops shall be installed parallel to the floor
framing members. Section R302.12.1
27. Under-stair protection. Enclosed space beneath stairs that are accessed by a door or panel shall have all interior
surfaces protected on the enclosed side with 1/2 inch gypsum board, unless both the dwelling unit and under –stair
area are protect with an approved fire sprinkler system. Section R302.7
28. Fire protection of floors. Floor assemblies that are not required elsewhere in this code to be fire-resistance rated, shall
be protected with a ½ inch gypsum wall-board membrane, 5/8 inch wood structural panel membrane, or equivalent on
the underside of the floor framing member. Penetrations or openings for ducts, vents, outlets, lighting, devices, wires,
piping, or other similar openings or penetrations shall be permitted. Section R302.13
Exceptions:
1. Floor assemblies located above a space protected by an approved fire sprinkler system.
2. Floor assemblies located directly over a crawl space not intended for storage or heating appliances.
3. Portions of floor assemblies shall be permitted to be unprotected where complying with the following:
a. The aggregate area of the unprotected portions does not exceed 80 square feet per story.
b. Fireblocking in accordance with Section R302.11.1 is installed along the perimeter of the unprotected
portion to separate the unprotected portion from the remainder of the floor assembly.
c. Wood floor assemblies using dimension lumber or structural composite lumber equal to or greater
than 2-inch by 10-inch nominal dimension, or other approved floor assemblies demonstrating
equivalent fire performance.
Garages and Carports
29. Floors. Garage and carport floors shall be of approved noncombustible materials. The area of floor used for parking of
automobiles or other vehicles shall be sloped to facilitate the movement of liquids to a drain or toward the main vehicle
entry doorway. Sections R309.1 and R309.2
Exception: Asphalt surfaces shall be permitted at ground level in carports.
30. Elevation of ignition source. Appliances having an ignition source shall be elevated such that the source of ignition is
not less than 18 inches above the floor in garages. For the purpose of this section, rooms or spaces that are not part of
the living space of a dwelling unit and that communicate with a private garage through openings shall be considered to
be a part of the garage. Section M1307.3
Exception: Elevation is not required for appliances that are listed as flammable-vapor-ignition resistant.
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31. Protection from impact. Appliances shall not be located in a location subject to vehicle impact except where protected
by approved barriers. Figure M1307.3.1 contains examples of normal vehicle paths and acceptable types of protection.
Section M1307.3.1
32. Garage separation. The garage shall be separated from the residence and attic areas in accordance with Table R302.6:
Table R302.6
Dwelling-Garage Separation
SEPARATION MATERIAL
From the residence and attics Not less than 1/2-inch gypsum board or eq
uivalent
applied to the garage side
From habitable rooms above the garage Not less than 5/8-
inch Type X gypsum board or
equivalent, attached per Table R702.3.5
Structure(s) supporting floor/ceiling assemblies used for
separation required by this section
Not less than 1/2-inch gypsum board or equivalent
Garages located less than 3 feet from a dwelling unit on the
same lot
Not less than ½-
inch gypsum board or equivalent
applied to the interior side of exterior walls that are
within this area
Exception: Separation is not required when both the dwelling and garage are protected by an approved
automatic sprinkler system.
33. Opening Protection. Openings between the garage and residence shall be equipped with solid wood doors not less than
1-3/8 inches in thickness, solid or honeycomb core steel doors not less than 1-3/8 inches thick, or 20-minute fire-rated
doors. Section R302.5.1.1
Exception: Opening protection is not required when both the dwelling and garage are protected by an
approved automatic sprinkler system.
34. Prohibited Openings. Openings from a private garage directly into a room used for sleeping purposes shall not be
permitted. Section R302.5.1
35. Penetrations. Ducts in the garage and ducts penetrating the walls or ceilings separating the dwelling from the garage
shall be constructed of a minimum 26 gauge sheet steel or other approved material, and shall have no openings into
the garage. When a vibration isolator is used in the garage duct, it must be installed not less than 18 inches from the
penetration. Other penetrations shall be protected with an approved material, filling the annular space to resist the
free passage of flame and products of combustion (but not required to meet ASTM E136). Sections R302.5.2 and
R302.5.3
Footings and Foundations
36. Minimum concrete compressive strength shall be in accordance with Table R402.2.
37. Footings. All exterior walls shall be supported on continuous solid or fully grouted or concrete footings, or other
materials as specified in Section R403.1 and shall be supported on undisturbed natural soil or engineered fill. Section
R403.1
38. Footings supporting deck posts shall provide lateral restraint with manufactured connectors or a minimum embedment
of 12 inches in accordance with R507.4.1
39. Minimum depth. All exterior footings, and interior footings supporting bearing walls or braced wall panels cast
monolithically with a slab, shall be placed a minimum of 12 inches below finished grade on undisturbed ground surface.
Bottoms of all footings supporting foundation walls, piers and other permanent supports shall also extend beyond the
frost depth (not less than 18 inches at/above 2,500’ and below 4,000’ elevation, and 24” at/above 4,000’ elevation)
unless otherwise protected in accordance with R403.1.4.1. Sections R403.1.3.4 and R403.1.4
Exception: Frost depth/protection is not required for decks not supported by a dwelling, or free-standing
accessory structures with an eave height of 10 feet or less and a building area of 600 square feet or less (400
square feet or less for other than light-frame construction).
40. Minimum size for continuous concrete or masonry footings shall be in accordance with Table R403.1 and Figure
R403.1(1) or R403.1.3, as applicable. Plain isolated square or round footings shall be permitted subject to the limitations
in R403.1.7.1 and R403.1.7.2. Deck footings shall be sized in accordance with Table R507.3.1. Sections R403.1.1,
R403.1.7, and R507.3.1
41. Slope. The top surface of footings shall be level. The bottom surface of footings shall not have a slope exceeding 1 in
10. Footings shall be stepped where it is necessary to change the elevation of the top surface of the footing or where
the slope of the bottom surface of the footing will exceed 1 in 10. Section R403.1.5
42. Ground clearance. Wood siding, sheathing and wall framing on the exterior of a building shall have a clearance of not
less than 6 inches from the ground. Section R317.1
43. Footings on or adjacent to slopes. The placement of buildings and structures on or adjacent to slopes steeper than one
unit vertical in three units horizontal (33% slope) shall conform to Sections R403.1.9.1 through R403.1.9.4. Refer to Fig.
R403.1.9.1.
44. Expansive soils. Foundations and floor slabs for buildings located on expansive soils shall be designed in accordance
with Chapter 18 of the Building Code (OSSC). Section R403.1.10
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45. Seismic reinforcing. Concrete stem walls and footings shall be provided with a minimum of one No. 4 bar within 12
inches of the top of the wall and within 3-4 inches of the bottom of the footing, with support and cover in accordance
with Section R403.1.3.5.
Exception: Foundations constructed monolithically shall be permitted to have a minimum of two No. 4 bars
placed in the footing. Section R403.1.3.3
Where a construction joint is created between a concrete footing and stem wall, a minimum of one No. 4 bar with
standard hook complying with R608.5.4.5 shall be provided at no more than 4 feet on center. The vertical bar shall
extend a minimum of 14 inches into the stemwall and to the bottom of the footing, with support and cover in
accordance with Section R403.1.3.5.3.
Where a grouted masonry stem wall is supported on a concrete footing and stem wall, a minimum of one
No. 4 bar shall be installed at not more than 4 feet on center which shall extend to 3 inches clear of the bottom
of the footing with a standard hook. Masonry stem walls without solid grout and vertical reinforcement are
not permitted. Section R403.1.3.2
Slabs on grade with turned-down footings cast monolithically shall have a minimum of one No. 4 bar at the
top and bottom of the footing, or one No. 5 bar or two No. 4 bars in the middle third of the footing depth.
Where a slab is not cast monolithically with the footing, No. 3 or larger vertical dowels with standard hooks
(complying with R608.5.4.5) on each end shall be installed at no more than 4 feet on center in accordance with
Fig. R403.1.3, Detail 2. Section R403.1.3.3.
46. Grounding electrodes. When concrete reinforcing bars are installed in concrete footings, the following requirements
shall be met to provide for a grounding electrode system:
1. Uncoated No. 4 reinforcing bar installed not less than 3 inches from the bottom of the footing and not less
than 20 feet in length encased with a minimum of 2 inches of concrete.
2. An uncoated No. 4 reinforcing bar stubbed up at least 12 inches above the floor plate line and tightly attached
to the reinforcing bar located in the footing. The spliced lap of the stubbed up bar to the footing bar shall be
a minimum of 12 inches. Section R403.1.8
47. Wood sill plate anchor bolts shall be min. 1/2-inch diameter, 7 inches embedment, max. 6 feet on center and not more
than 12 inches from a corner or less than 7 bolt diameters from mudsill splice. Min. 2 anchor bolts per plate. These
requirements apply to all exterior walls, interior braced panel walls and interior load bearing walls. Walls connecting
offset braced wall panels and 24 inches or shorter in length are permitted to be connected to the foundation with one
anchor bolt located in the middle third of the plate, and walls 12 inches or shorter in length are permitted without
anchorage to the foundation, as long as such walls are connected to the adjacent braced panels at the corners as shown
in Item 9 of Table R602.3(1). Steel framing shall be anchored in accordance with Section R505.3.1 or R603.3.1, as
applicable. Sections R403.1.6 and R403.1.6.1.
Plate washers conforming to Section R602.11.1 shall be provided for all anchor bolts over the full length of
required braced wall lines. Properly sized cut washers shall be permitted for anchor bolts in wall lines not
containing braced wall panels. Plate washers, a minimum of 0.229 inches by 3 inches by 3 inches in size, shall
be installed between the foundation sill plate and the nut. The hole in the plate washer is permitted to be
diagonally slotted with a width of up to 3/16 inch larger than the bolt diameter and a slot length not to exceed
1-3/4 inches, provided a standard cut washer is placed between the plate washer and the nut. See Section
R602.11.1.
48. Concrete slab on ground floors shall be not less than 3 1/2 inches thick. Section R506.1
49. Foundation walls. Concrete and Masonry foundation walls shall be constructed in accordance with Section R404.1.
50. Retaining Walls: Retaining walls that are not laterally supported at the top and that retain in excess of 48 inches of
unbalanced fill or retaining walls exceeding 24 inches in height that resist lateral loads in addition to soil shall be
designed in accordance with accepted engineering practice to ensure stability against overturning, sliding, excessive
foundation pressure and water uplift in accordance with the design principles of the Building Code (OSSC). A minimum
factor of safety of 1.5 shall be used against sliding and overturning. This section shall not apply to foundation walls
supporting buildings. Section R404.4.
51. Surface drainage. Lots shall be graded to to drain surface water away from foundation walls, and grade shall fall a
minimum of 6 inches within 10 feet of foundations. Section R401.3.
Exception: Where lot lines, walls, slopes or other physical barriers prohibit 6 inches of fall within 10 feet, drains,
swales, or other means shall be provided, and shall be constructed to ensure drainage away from the structure.
Impervious surfaces within 10 feet of the building foundation shall be sloped a minimum of 2 percent away
from the building.
52. Foundation drainage and waterproofing. Drains shall be provided around all concrete or masonry foundations that
retain earth AND enclose habitable or usable space (except when the foundation is installed on a well-drained ground
or sand-gravel mixture soils) in accordance with Section R405. Such walls requiring drainage system shall also be
required to be waterproofed in accordance with Section R406.
Crawl Spaces
53. Access opening. Crawl space openings through a floor shall be a minimum of 18 inches by 24 inches. Openings through
a perimeter wall shall be not less than 16 inches by 24 inches. When any portion of the through-wall access is below
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grade, an areaway not less than 16 inches by 24 inches shall be provided and the bottom of the areaway shall be below
the threshold of the access opening. Through wall access opening shall not be located under a door to the residence.
Pipes, ducts and other construction must not obstruct accessibility to and within the crawl space. See Section M1305.1.4
for mechanical equipment access. Section R408.4
54. Under-floor space ventilation. The under-floor space between the bottom of the floor joists and the earth under any
building (except space occupied by a basement) shall have ventilation openings through foundation walls or exterior
walls. The minimum net area of ventilation openings shall not be less than 1 square foot for each 150 square feet of
under-floor space area, and may not be reduced due to radon mitigation requirements. Ventilating openings shall be
placed so as to provide cross ventilation of the space with one such opening located within 3 feet of each corner of the
building. Ventilation openings shall be covered with corrosion resistant wire mesh or equivalent with the least
dimension being 1/8-inch thick. Unvented crawlspaces are not allowed in new construction within Clackamas County
where radon mitigating construction is required. Ground surfaces shall be covered by a Class I vapor retarder lapped at
joints, and extending up perimeter walls, a minimum of 12 inches. Sections R408.1, R408.2, and R408.3
Exceptions:
1. Ventilation openings may be omitted on one side of a building.
2. Ventilation openings may be omitted when continuously operated mechanical ventilation is installed, with
a capacity to exhaust 1.0 cfm for each 50 square feet of crawl space floor area.
3. Ventilation openings in townhouses shall be permitted to be omitted on two sides when adjoining adjacent
dwellings.
55. Drainage. Provide water drainage from the crawl space by means of crawl space and foundation drains sloped for
gravity drainage and extending to a storm sewer, street gutter, road ditch or other drainage way or raise the finish grade
in the crawl space to the level of finish grade outside. Section R408.6
56. Removal of debris. The under-floor grade shall be cleaned of all vegetation and organic material. All wood forms used
for placing concrete shall be removed before a building is occupied or used for any purpose. All construction materials
shall be removed before a building is occupied or used for any purpose. Section R408.5
Protection Against Decay
57. Location required. Protection from decay shall be provided in the following locations by the use of naturally durable
wood or wood that is preservative treated in accordance with AWPA U1 for species, product, preservative and end use.
Preservatives shall be listed in Section 4 of AWPA U1. Sections R317.1, R317.1.2 and R317.3
1. Wood joists or bottom of wood structural floor when closer than 18 inches or wood girders when closer than
12 inches to exposed ground in crawl spaces or unexcavated area located within the periphery of the building
foundation.
2. Wood framing members and sill plates in contact with concrete or masonry foundation walls.
3. Sills and sleepers on a concrete or masonry slab that is in direct contact with the ground unless separated from
such slab by an impervious moisture barrier such as 6-mil polyethylene sheeting or equivalent.
4. The ends of wood girders entering exterior masonry or concrete walls having clearances of less than 0.5 inches
on tops, sides and ends.
5. Wood siding, sheathing and wall framing on the exterior of a building having a clearance of less than 6 inches
from the ground or less than 2 inches measured vertically from concrete steps, porch slabs, patio slabs, and
similar horizontal surfaces exposed to the weather.
6. Wood structural members supporting moisture permeable floors or roofs that are exposed to the weather,
such as concrete or masonry slabs, unless separated from such floors or roofs by an impervious moisture
barrier.
7. Wood furring strips or other wood framing members attached directly to the interior of exterior masonry walls
or concrete walls below grade except where an approved vapor retarder is applied between the wall and the
furring strips or framing members.
8. Exposed wood members and glued-laminated timbers that form the structural supports for buildings,
balconies, porches, or similar building appurtenances when those members are exposed to the weather
without adequate protection from a roof, eave, overhang, or other covering which would moisture or water
accumulation on the surface or at joints between members (both horizontal and vertical members).
9. All wood in contact with the ground, embedded in concrete in direct contact with the ground or embedded in
concrete exposed to the weather that supports permanent structures intended for human occupancy shall be
approved pressure-preservative-treated wood suitable for ground contact use, except untreated wood may be
used where entirely below groundwater level or continuously submerged in fresh water.
58. Field treatment. Field-cut ends, notches and drilled holes or preservative-treated wood shall be treated in the field in
accordance with AWPA M4. Section R317.1.1
59. Wood columns. Wood columns shall be approved wood of natural decay resistance or approved pressure-preservative-
treated wood. Section R317.1.4
Exceptions:
1. Columns exposed to the weather or in basements when supported by concrete piers or metal pedestals
projecting 1 inch above a concrete floor or 6 inches above exposed earth and the earth is covered by an
approved impervious moisture barrier.
2. Columns in enclosed crawl spaces or unexcavated areas located within the periphery of the building when
supported by a concrete pier or metal pedestal at a height more than 8 inches from exposed earth and the
earth is covered by an impervious moisture barrier.
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3. Deck posts supported by concrete piers or metal pedestals projecting not less than 1 inch above a concrete
floor or 6 inches above exposed earth.
60. Fasteners. Fasteners, nut and washers for pressure-preservative and fire-retardant-treated wood shall be of hot-dipped
zinc-coated galvanized steel, stainless steel, silicon bronze or copper (staples shall be stainless steel only). Coating types
and weights for connectors in contact with preservative-treated wood shall be in accordance with the connector
manufacturer’s recommendations. In the absence of manufacturer’s recommendations, a minimum of ASTMA653 type
G185 zinc-coated galvanized steel, or equivalent shall be used. Section R317.3.1
Exceptions:
1. One-half-inch diameter or larger steel bolts.
2. Fasteners other than nails and timber rivets shall be permitted to be of mechanically deposited zinc-coated
steel with coating weights in accordance with ASTM B 695, Class 55, minimum.
3. Plain carbon steel fasteners in SBX/DOT and zinc borate preservative-treated wood in an interior, dry
environment shall be permitted.
Framing
61. Grading and fasteners. Load bearing dimension lumber (including logs used in log home construction) for joists, beams,
girders, and rafters shall be identified by a grade mark of a lumber grading or inspection agency that has been approved
by an accredited body that complies with DOC PS 20. In lieu of a grade mark, a certificate of inspection issued by a
compliant lumber grading or inspection agency shall be acceptable. Used or salvaged dimensional lumber which is in
good condition, free of decay, and approved by the building official may be assumed to be DFL #2. Refer to Tables
R602.3 (1) & R602.3 (2) for fastener (nails, staples, etc.) requirements. Sections R104.9.1, R502, R602 and R802.1.1.
62. Joists under bearing partitions shall be of adequate size to support the load. Double joists, sized to adequately support
the load, that are separated to permit the installation of piping or vents shall be full depth solid blocked with lumber
not less than 2 inches in nominal thickness spaced not more than 4 feet on center. Bearing partitions perpendicular to
joists shall not be offset from supporting girders, walls or partitions more than the joist depth unless such joists are of
sufficient size to carry the additional load. Section 502.4
63. Bearing. Joists and beams or girders must have not less than 1 1/2 inches of bearing on wood or metal or 3 inches on
concrete or masonry except where supported on a 1-inch-by-4-inch ribbon strip and nailed to the adjacent stud or by
the use of approved joist hangers. Joist framing from opposite sides over a bearing support shall lap a minimum of 3
inches and shall be nailed together with a minimum of three 10d face nails (a wood or metal splice with strength equal
to or greater than that provided by the nailed lap is permitted). Joist framing into the side of a wood girder shall be
supported by approved framing anchors or on ledger strips not less than nominal 2 inches by 2 inches. Section R502.6
64. Cripple walls. Foundation cripple walls shall be framed of studs not less in size than the studding above. When
exceeding 4 feet in height, such walls shall be framed of studs having the size required for an additional story. Exterior
cripple walls with a stud height less than 14 inches shall be continuously sheathed on at least one side with wood
structural panel that is fastened to both the top and bottom plates in accordance with Table 602.3(1), or the cripple
walls shall be constructed of solid blocking. Cripple walls shall be supported on continuous foundations and braced as
required for lateral loads in accordance with Sections R602.10.10. Sections R602.9 and R602.10.10
65. Lateral restraint at supports. Joists shall be supported laterally at the ends by full-depth solid blocking not less than 2
inches nominal thickness; or by attachment to a full-depth header, band or rim joist, or to an adjoining stud or otherwise
provided with lateral support to prevent rotation. Joists exceeding a nominal 2 inches by 12 inches shall be supported
laterally by solid blocking, diagonal bridging (wood or metal), or a continuous 1 inch by 3 inch strip nailed across the
bottom of joists perpendicular to joists at intervals not exceeding 8 feet. Section R502.7, Section R502.7.1
Exception: Trusses, structural composite lumber, structural glued-laminated members and I-joists shall be
supported laterally as required by the manufacturer’s recommendations.
66. Columns: Wood columns shall not be less than 4 inch by 4 inch and protected from decay in accordance with R317.
Steel columns shall not be less than 3 inch diameter, schedule 40 pipe, and shall be given a shop coat of rust-inhibitive
paint (except for corrosion-resistant steel). Columns shall be restrained to prevent lateral displacement at the bottom
end, except those located within enclosed continuous foundations, supported on a pier or footing, and not exceeding
48 inches in height. Section R407.3
67. Plywood gussets. Where post and beam or girder construction is used to support floor framing, positive connections
shall be provided to ensure against lateral displacement. See Figure R502.9 for typical plywood gusset connections at
all post-to-beam connections. Gusset dimensions shall be a minimum of twice the beam height and the width of the
post/column. Lateral bracing is required at the bottom end of posts exceeding 4'-0" in length (for posts up to 8 feet in
height, this may be accomplished using gussets at each side of the post plus an angled 1x4 brace in accordance with Fig.
R502.9). Section R502.9
Exception: Girders and posts supporting exterior decks not exceeding 18 inches in height are not required to
be laterally braced or have a gusset at post and girder connections.
68. Wood floor and roof trusses shall be designed in accordance with approved engineering practice, and shop drawings
shall be prepared by a registered design professional. Trusses shall not be cut, notched, spliced, drilled or otherwise
altered without the approval of a registered design professional. All changes to approved truss layouts and designs must
be submitted for review and approval prior to installation. Sections R502.11 and R802.10
69. Prefabricated I-joists. I-joist layouts and schedules, and all changes thereof, shall be submitted for review and approval
prior to installation. Sections R106.1 and R502.1.2.
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70. Floor sheathing. Maximum allowable spans and minimum thicknesses required for lumber used as floor sheathing shall
conform to Tables R503.1, R503.2.1.1(1), and R503.2.1.1(2). Section R503.
71. Decks: When supported by attachment to an exterior wall, decks shall be positively connected to the primary system
for both vertical and lateral loads by means of a minimum ½ inch, galvanized or stainless lag screws or bolts in
accordance with Table R507.9.1.3(1). Such lag screws and bolts shall be placed in accordance with Figure R507.9.1.3(2).
In addition, hold-down tension devices shall be required to be installed per Figure R507.9.2(1) or Figure R507.9.2(2).
Framing members may be cantilevered up to 25% of the allowable span (or the maximum length per Table R507.6 for
joists, whichever is less) unless otherwise designed and constructed to resist uplift resulting from the full live load acting
on the cantilevered portion of the framing in accordance with accepted engineering practice. Joists supporting decking
shall be spaced in accordance with Table R507.6, and decking shall be fastened with not less than (2) 8d threaded nails
or (2) No. 8 wood screws. Decks that do not meet the above requirements shall be designed and constructed as a self-
supporting structure. Sections R301.1.3 and R507
72. Wall bracing. Changes to prescriptive wall bracing plans, and/or changes to a lateral design by a registered design
professional, shall be submitted as plan revisions for review and approval prior to installation. Sections R106.1.3,
R106.3.4, R106.4, and R602.10
73. Braced wall connections and support. Braced panels shall be connected to floor framing or foundations in accordance
with R602.10.8 and roof framing in accordance with R602.10.8.2. Braced wall panel support shall be provided per
R602.10.9. Braced wall line sills shall be anchored to foundations in accordance with Sections R403.1.6 and R602.11.1.
74. Wall studs shall be continuous from support at the sole plate to a support at the top plate to resist loads perpendicular
to the wall. The support shall be a foundation or floor, ceiling or roof diaphragm or shall be designed in accordance with
acceptable engineering practice. Exception: Jack studs, trimmer studs and cripple studs at openings in walls that comply
with Table R602.7(1) and R602.7(2). Section R602.3
Stud size, height and spacing shall be in accordance with Table R602.3(5). Section R602.3.1
Exceptions:
1. Utility grade studs shall not be spaced more than 16 inches on center, shall not support more than a
roof and ceiling, and shall not exceed 8 feet in height for exterior and load bearing walls or 10 feet for
interior nonload-bearing walls.
2. Where snow loads are less than or equal to 25psf, and the basic design wind speed is less than or
equal to 130mph, 2x6 studs supporting a roof load with not more than 6 feet of tributary length shall
have a maximum height of 18 feet where spaced at 16 inches on center, or 20 feet where spaced at
12 inches on center. Studs shall be a minimum No. 2 grade lumber.
Stud grade. Studs shall be a minimum No. 3, standard or stud grade lumber. Section R602.2
Exception: Bearing studs not supporting floors and nonbearing studs may be Utility grade lumber,
provided the studs are spaced in accordance with Table R602.3(5).
75. Rafter framing details. Rafters shall be framed not more than 1-1/2 inches offset from each other to a ridge board, or
directly opposite from each other with a collar tie, gusset plate, or ridge strap in accordance with Section R802.4.6 and
Table R602.3(1). Ridge boards shall be at least 1-inch nominal thickness and not less in depth than the cut end of the
rafter. At all valleys and hips there shall be a valley or hip rafter not less than 2-inch nominal thickness and not less in
depth than the cut end of the rafter. Hip and valley rafters shall be supported at the ridge by a brace to a bearing
partition or be designed to carry and distribute the specific load at that point. Where the roof pitch is less than 3 units
vertical in 12 units horizontal, structural members that support rafters and ceiling joists, such as ridge beams, hips and
valleys, shall be designed as beams. Sections R802.3 and R802.4
76. Ceiling joist and rafter connections. Where they are parallel, ceiling joists shall be connected to rafters at the top wall
plate in accordance with Table R802.5.2. Where ceiling joists are not connected to rafters at the top wall plate, they
shall be installed in the bottom third of the rafter height in accordance with Figure R802.4.5 and Table R802.5.2. Where
the ceiling joists are installed above the bottom third of the rafter height, the ridge shall be designed as a beam. Where
ceiling joists do not run parallel to rafters, they shall be connected to top plates in accordance with Table R602.3(1).
Each rafter shall be tied across the structure with a rafter tie in a 2x4 kicker connected to the ceiling diaphragm with
nails equivalent in capacity to Table R802.5.2. Section R802.5.2
77. Ceiling joists lapped. Ends of ceiling joists shall be lapped a minimum of 3 inches or butted over bearing partitions or
beams and toenailed to the bearing members. Where ceiling joists are used to resist rafter thrust, lapped joists shall be
nailed together in accordance with Table R802.5.2 and butted joists shall be tied together in a manner to resist such
thrust. Roof sheathing shall not cantilever more than 9 inches beyond a gable endwall unless supported by gable
overhang framing. Section R802.5.2.1
78. Bearing. The ends of each rafter or ceiling joist shall have not less than 1 1/2 inches of bearing on wood or metal and
not less than 3 inches on masonry. Section R802.6
79. Lateral support. Rafters and ceiling joists having a depth-to-thickness ratio exceeding 5 to 1 based on nominal
dimensions shall be provided with lateral support at points of bearing to prevent rotation. Section R802.8
80. Truss/rafter uplift resistance. Trusses shall be connected to supporting wall assemblies by connections capable of
resisting uplift forces as specified on the approved truss design drawings. Individual rafters shall be connected to
supporting wall assemblies by connections capable of resisting uplift forces as determined by Table R802.11 or as
determined by accepted engineering practice. Sections R802.11.1
CLACKAMAS COUNTY – 2021 RESIDENTIAL CODE SUMMARY
Oregon codes are available for viewing online at: Oregon.gov/bcd. CCP-PW29 (Rev. 11/21)
81. Lumber sheathing. Allowable spans for lumber used as roof sheathing shall conform to Table R803.1. Spaced lumber
sheathing for wood shingles and shake roofing shall conform to the requirements of Section R905.7 and R905.8. Section
R803.1
Wall and Ceiling Covering
82. Gypsum wallboard shall be installed in accordance with Section R702.3, with fastening in accordance with Table
R702.3.5.
83. Flame spread. Wall and ceiling finishes other than trim shall have a flame spread classification of not greater than 200
and a smoke-developed index of not greater than 450. Section R302.9
84. Installation. Products sensitive to adverse weather shall not be installed until after adequate weather protection is
provided. Exterior sheathing shall be dry before applying exterior cover. Section R701.2
85. Exterior Wall Envelope: The exterior wall envelope shall be installed in a manner that water that enters the assembly
can drain to the exterior. The envelope shall consist of an exterior veneer, a water-resistive barrier, a minimum 1/8 inch
space between the water-resistive barrier and the exterior veneer, and integrated flashings. See Section R703.1.1 for
exceptions to this requirement. Section R703.1
86. Water-resistive barrier. One layer of No. 15 asphalt felt, free from holes and breaks, complying with ASTM D 226 for
Type 1 felt or other approved water-resistive barrier shall be applied over studs or sheathing of all exterior walls. Such
felt or material shall be applied horizontally, with the upper layer lapped over the lower layer not less than 2 inches.
Where joints occur, felt shall be lapped not less than 6 inches. Approved materials other than felt shall be installed in
accordance with the manufacturer’s installation instructions. The felt or other approved materials shall be continuous
to the top of walls and terminated at penetrations and building appendages in a manner to meet the requirements of
the exterior wall envelope as described in Section R703.2.
87. Siding. Weather resistant siding shall be installed in accordance with R703.3, R703.5 and R703.6.
88. Stone and Masonry Veneer. Such veneers installed over a backing of wood or cold formed steel shall be limited to the
first story above grade and shall not exceed 5 inches in thickness. Section R703.8
Exceptions:
1. Veneers up to 20 feet in height are permissible in structures without cripple walls above noncombustible
foundations, with a maximum 4 inch thickness and a maximum weight limited to 40 psf. Table R703.8(2)
2. The limitations listed above do not apply where full height veneer does not exceed 25% of the total braced
wall perimeter and not more than 40% of an exterior braced wall line.
Flashing. Approved corrosion-resistive flashing shall be applied shingle-fashion in such a manner to prevent entry of
water into the wall cavity or penetration of water to the building structural framing components, and shall extend to
the surface of the exterior wall finish. Per Section R703.4, required locations include:
1. Exterior window and door openings. Flashing at exterior window and door openings shall extend to the surface
of the exterior wall finish or to the water-resistive barrier for subsequent drainage.
2. At the intersection of chimneys or other masonry construction with frame or stucco walls, with projecting lips
on both sides under stucco copings.
3. Under and at the ends of masonry, wood or metal copings and sills.
4. Continuously above all projecting wood trim.
5. Where exterior porches, decks or stairs attach to a wall or floor assembly of wood-framed construction.
6. At wall and roof intersections: kick-out per Figure R703.4(1).
7. At built-in gutters.
Roof and Attic Spaces
89. Roof drainage control. All dwellings and non-exempt accessory structures located below 1,500 foot elevation shall
have a controlled method of water disposal from roofs that will collect and discharge all roof drainage in accordance
with the Plumbing Code. Section R801.4.
90. Attic access. Buildings with combustible ceiling or roof construction shall have an attic access opening to attic areas
that have a vertical height of 30 inches or greater (measured from the top of ceiling framing members to the underside
of roof framing members) over an area of not less than 30 square feet. The rough-framed access opening shall be not
less than 22 inches by 30 inches and shall be located in a hallway or other readily accessible location. Where located in
a wall, the opening shall be not less than 22 inches wide by 30 inches high. Where access is located in a ceiling, minimum
obstructed headroom in the attic space shall be 30 inches at some point above the access measured vertically from the
bottom of ceiling framing members. Section R807.1
91. Ventilation required. Enclosed attics and enclosed rafter spaces formed where ceiling is applied to the underside of
roof rafters shall have cross ventilation for each separate space by ventilated openings protected against the entrance
of rain or snow. Ventilation openings shall be provided with corrosion-resistant wire cloth, hardware cloth, perforated
vinyl, or similar material with 1/16 inch minimum to 1/4 inch maximum openings. At eave and cornice vents, not less
than a 1 inch space shall be provided between the insulation and roof sheathing at the location of the vent. Section
R806.
Baffles. Baffles of a durable rigid material shall be provided to prevent obstruction of vent openings and to
deflect incoming air above the surface of porous insulation so as to prevent wind washing and blowing of loose
material. Thermal insulation shall not be installed in a manner that would obstruct openings required for attic
ventilation. Section N1104.2.5
CLACKAMAS COUNTY – 2021 RESIDENTIAL CODE SUMMARY
Oregon codes are available for viewing online at: Oregon.gov/bcd. CCP-PW29 (Rev. 11/21)
Unvented attic assemblies: Specific requirements apply - refer to Section R806.5
92. Minimum area. The total net free ventilating area shall be not less than 1/150 of the space ventilated. The area may
be reduced to 1/300 of the vented space provided one or more of the following conditions are met: 1.When a class I
or II vapor retarder is installed on the warm-in-winter side of the ceiling. Or, 2. Not less than 40 percent but not more
than 50 percent of the required ventilation area is provided by ventilators located in the upper portion or the attic or
rafter space. Upper ventilators shall be located not more than 3 feet below the ridge or highest point of the space,
measured vertically, with the balance of the required ventilation provided by eave or cornice vents. Section R806.2
Roof Coverings
93. Underlayment shall be applied in accordance with Table R905.1.1(2) and attached in accordance with Table R9051.1(3).
Ice barriers shall be installed on structures (except unconditioned, detached accessory structures) located at elevations
above 1,500 feet in accordance with Section R905.1.2.
94. Application and fasteners for roof covering shall be in accordance with Section R905 and the product installation
instructions by the manufacturer, based on type of material used. In all cases, fasteners shall be long enough to
penetrate into roof sheathing 3/4 inches or through the thickness of sheathing, whichever is less.
95. Flashing shall be installed in a manner that prevents moisture from entering the wall and roof through joints in coping,
through moisture permeable materials and at intersections with parapet walls and other penetrations through the roof
plane such as at junctions of chimneys and roofs, in roof valleys and around all roof openings. A drip edge shall be
provided at eaves and rake edges of shingle roofs. Section R903.2
Chimneys and Fireplaces
96. Spark arrester. Chimneys for dwellings located on land which is zoned forest shall have a spark arrester. ORS 215.730
97. Seismic reinforcing and anchorage. Masonry or concrete chimneys shall be reinforced in accordance with Table
R1001.1 and Section R606, and anchored to floor/ceiling framing in accordance with Section 1001.4.1 and R1003.4.
Sections R1001.3 and R1003.3
98. Foundation. Masonry fireplaces and their chimneys shall be supported on foundations of solid masonry or concrete at
least 12 inches thick and shall extend at least 6 inches beyond the face of the fireplace or foundation wall on all sides.
Footings shall be placed on natural, undisturbed earth or engineered fill below frost depth. In areas not subjected to
freezing, footings shall be at least 12 inches below finished grade. Sections R1001.2 and R1003.2
99. Termination. Chimneys shall extend at least 2 feet higher than any portion of the building within 10 feet, but shall not
be less than 3 feet above the highest point where the chimney passes through the roof. Section R1003.9
100. Fireplace clearances. All wood beams, joists, studs and other combustible materials shall have a clearance of not less
than 2 inches from the front faces and sides of the masonry fireplace and not less than 4 inches from the back faces of
masonry fireplaces. The air space shall not be filled, except to provide fire blocking in accordance with Section R1001.12.
Section R1001.11
101. Chimney clearances. Any portion of masonry chimney located in the interior of the building or within the exterior wall
of the building shall have a minimum air space clearance to combustibles of 2 inches. Chimneys located entirely outside
the exterior walls of the building, including chimneys that pass through the soffit or cornice, shall have a minimum air
space clearance of 1 inch. The air space shall not be filled, except to provide fire blocking in accordance with Section
R1003.19. Section R1003.18
102. Chimney crickets. Chimney shall be provided with crickets when the dimension parallel to the ridgeline is greater than
30 inches and does not intersect the ridgeline. The intersection of the cricket and the chimney shall be flashed and
counter flashed in the same manner as normal roof-chimney intersections. Crickets shall be constructed in compliance
with Figure R1003.20 and Table R1003.20. Section R1003.20
103. Lintel and throat. Masonry over a fireplace opening shall be supported by a lintel of noncombustible material. The
minimum required bearing length on each end of the fireplace opening shall be 4 inches. The fireplace throat or damper
shall be located a minimum of 8 inches above the lintel. Section R1001.7
104. Mantel and trim. Woodwork or other combustible materials shall not be placed within 6 inches of fireplace opening.
Combustible material within 12 inches of the fireplace opening shall not project more than 1/8 inch for each 1-inch
distance from such opening. Section R1001.11 (Exception 4)
105. Hearth and hearth extensions. Masonry fireplaces hearths and hearth extensions shall be constructed of concrete or
masonry, supported by noncombustible materials and reinforced to carry their own weight and all imposed loads. No
combustible material shall remain against the underside of hearths and hearth extensions after construction. Sections
R1001.9 and R1001.10
Hearth thickness. The minimum thickness of fireplace hearths shall be 4 inches. Section R1001.9.1
Hearth extension dimensions. Hearth extensions shall extend at least 16 inches in front inches in front of and
at least 8 inches beyond each side of the fireplace opening. Where the fireplace opening is 6 square feet or
larger, the hearth extension shall extend at least 20 inches in front of, and at least 12 inches beyond, each side
of the fireplace opening. Section R1001.10
106. Exterior air. Factory-built or masonry fireplaces covered in Chapter 10 shall be equipped with an exterior air supply to
ensure proper fuel combustion unless the room is mechanically ventilated and controlled so that indoor pressure is
neutral or positive. Section R1006.1.
CLACKAMAS COUNTY – 2021 RESIDENTIAL CODE SUMMARY
Oregon codes are available for viewing online at: Oregon.gov/bcd. CCP-PW29 (Rev. 11/21)
Exterior air intake. The exterior air intake shall be capable of supplying all combustion air from the exterior of
the dwelling or from spaces within the dwelling ventilated with outside air such as non-mechanically ventilated
crawl or attic spaces. The exterior air intake shall not be located within the garage or basement of the dwelling
nor shall the air intake be located at an elevation higher than the firebox. The exterior air intake shall be
covered with a corrosion-resistant screen of 1/4-inch mesh. Section R1006.2
Mechanical
107. Listed and labeled. Appliances regulated by this code shall be listed and labeled for the application in which they are
installed and used, unless otherwise approved in accordance with Section R104.11. Section M1302.1
108. Appliance access for inspection service, repair and replacement. Appliances shall be accessible for inspection, service,
repair and replacement without removing permanent construction, other appliances, or any piping or ducts not
connected to the appliance being inspected, serviced, repaired or replaced. A level working space at least 30 inches
deep and 30 inches wide shall be provided in front of the control side to service an appliance. Section M1305.1
Appliances in rooms. Where installed in a compartment, alcove, basement or similar space shall be accessed by a
door or opening and an unobstructed passageway not less than 24 inches wide and large enough to allow the
removal of the largest appliance in the space, with a level service space not less than 30 inches deep and the height
of the appliance (but not less than 30 inches) at the front or service side of the appliance with the door open.
Appliances in attics. Attics containing appliances requiring access shall be provided with an opening and a clear
and unobstructed passageway large enough to allow removal of the largest appliance, but not less than 30” high
and 22” wide and not more than 20 feet in length when measured along the centerline of the passageway from the
opening to the appliance. The passageway shall have continuous solid flooring not less than 24” wide. A level
service space at least 30” deep and 30” wide shall be present along all sides of the appliance where access is
required. The clear access opening dimensions shall be a minimum of 20 inches by 30 inches and large enough to
allow removal of the largest appliance.
Exceptions:
1. The passageway and level service space are not required where the appliance is capable of being serviced
and removed through the required opening.
2. Where the passageway is unobstructed and not less than 6 feet high and 22 inches wide for its entire
length, the passageway shall not be more than 50 feet long.
3. In existing structures the access opening shall be large enough for removal and replacement of the largest
piece of the equipment.
Appliances under floors. Underfloor spaces containing appliances requiring access shall be provided with an
opening and a clear and unobstructed passageway large enough to allow removal of the largest appliance, but not
less than 30” high and 22” wide and not more than 20 feet in length when measured along the centerline of the
passageway from the opening to the appliance. A level service space at least 30” deep and 30” wide shall be present
at the front or service side of the appliance. If the depth of the passageway or service space exceeds 12 inches
below adjoining grade, the passageway walls shall be lined with concrete or masonry extending 4 inches above the
adjoining grade. The clear access opening dimensions shall be a minimum of 20 inches by 30 inches and large
enough to allow removal of the largest appliance.
Exceptions:
1. The passageway is not required where the level service space is present when the access is open, and the
appliance can be serviced and removed through the opening.
2. Where the passageway is unobstructed and not less than 6 feet high and 22 inches wide for its entire
length, the passageway shall not be limited in length.
3. In existing structures, the access opening shall be large enough for the removal and replacement of the
largest piece of equipment.
Electrical requirements. Where appliances are located in attics or under floors, a luminaire controlled by a switch
located at the passageway opening and a receptacle outlet shall be installed at or near the appliance location in
accordance with the Electrical Code.
109. Clearances. Equipment and appliances supported from the ground shall be firmly supported on a level concrete slab or
other approved material extending not less than 3 inches above the adjoining ground, and in accordance with the
manufacturer’s installation instructions. Appliances suspended from the floor shall have a clearance of not less than 6
inches from the ground. Appliances shall be installed with the clearances from unprotected combustible materials as
indicated on the appliance label and in the manufacturer’s installation instructions. For possible reductions, refer to
Section and Table M1306.2. Sections M1305 and M1306
110. Installation. Heating and cooling equipment and appliances shall be installed in accordance with the manufacturer’s
installation instructions and the requirements of ORSC Chapters 14 and 24. The equipment shall be sized based on
building loads calculated in accordance with ACCA Manual S or other approved heating and cooling calculation
methodologies based on building loads calculated in accordance with ACCA Manual J. Sections M1401 and G2401.1
111. Fuel-gas piping shall be sized and installed in accordance with Chapter 24. Where 4 or more appliances are served on a
system, a pipe-sizing diagram demonstrating compliance with Section G2413.3 shall be submitted for review and
approval prior to rough-in inspection per county policy.
CLACKAMAS COUNTY – 2021 RESIDENTIAL CODE SUMMARY
Oregon codes are available for viewing online at: Oregon.gov/bcd. CCP-PW29 (Rev. 11/21)
112. Duct systems shall be installed in accordance with Section M1601 and ACCA Manual D, or the installation instructions
by the manufacturer. Except as allowed per M1601.1.1, building cavities and crawlspaces shall not be used for air duct
or plenums in new construction or additions to existing structures.
Joints, seams and connections shall be securely fastened and sealed in accordance with M1601.4.1. Tape shall
not be used to seal metal ductwork, or used as the only sealing method between metal duct and flexible or
fibrous duct. Tape is permitted to be used with metal duct at connections to equipment requiring future
replacement. Closure systems shall be installed in accordance with the manufacturer’s instructions.
Conditioned air ducts shall be located fully within the building envelope or buried within R-8 insulation (with
gaps and voids between ductwork and ceilings filled with insulation, a minimum of R-19 above ducts where
located in unconditioned attics, and depth marker flags installed every 10 feet) in accordance with N1105.
Exceptions:
4. Exhaust and intake ductwork.
5. The replacement or addition of a furnace, air conditioner, or heat pump shall not require existing
ducts to be insulated to current requirements.
6. Up to 5% of a system’s ductwork may be located outside of the thermal envelope.
113. Exhaust openings. The air removed by every mechanical exhaust system shall be discharged to the outdoors. Air shall
not be exhausted into an attic, soffit, ridge vent, crawlspace, or onto walkways.
Exception: Whole-house ventilation-type attic fans that discharge into the attic space of dwelling units having
private attics shall be permitted.
Exhaust openings shall terminate not less than 3 feet from gravity air intake openings and operable windows/doors,
and not less than 10 feet from mechanical air intake openings (except where the exhaust openings is located not less
than 3 feet above the air intake opening). Outdoor termination openings shall be protected against local weather
conditions and with corrosion-resistant screens, louvers or grilles with an opening size not less than 1/4 inch and not
greater than 1/2 inch. Sections R303.5, M1501.1, and M1504.3
Recirculation of air. Exhaust air from range hoods, bathrooms, toilet rooms and rooms with bathing or spa
facilities shall not be recirculated within a residence or to another dwelling unit and shall be exhausted directly
to the outdoors. Exhaust air from range hoods, bathrooms, toilet rooms and rooms with bathing or spa
facilities shall not discharge into an attic, crawl space or other areas inside the building. Section M1507.2
114. Air intake openings shall be located not less than 10 feet from sources of hazardous or noxious contaminants, such as
vents, chimneys, or locations where motor vehicles operate. Section R303.5
Exception: 10 foot separation is not required where the intake opening is located 3 feet or more below the
contaminant source.
115. Clothes dryer exhaust. Dryer exhaust systems shall be independent of all other systems, shall convey the moisture to
the outdoors and shall terminate on the outside of the building. Exhaust duct terminations shall be made with a full
opening exhaust outlet or in accordance with the dryer manufacturer’s installation instructions. Screens shall not be
installed at the duct termination. Exhaust ducts shall not be connected with sheet-metal screws or fastening means
which extend into the duct. Exhaust ducts shall be equipped with a backdraft damper. The entire exhaust system,
excluding transition ducts, shall be supported and secured in place. Exhaust ducts shall be constructed of minimum
0.0157-inch-thick rigid metal ducts, having smooth interior surfaces with joints running in the direction of airflow.
Flexible transition ducts used to connect the dryer to the exhaust duct system shall be limited to single length, not to
exceed 8 feet in length. Transition ducts shall not be concealed within construction. Section M1502
Exhaust duct size. The diameter of the exhaust duct shall be a minimum of 4 inches or as required by the
clothes dryer’s listing and the manufacturer’s installation instructions. Section M1502.4.1
Length limitation. The maximum length of a clothes dryer exhaust duct shall not exceed 35 feet from the dryer
location to the wall or roof termination. The length reduction of the duct for fittings shall comply with tables
1502.4.4.1. The maximum length of the exhaust duct does not include the transition duct. Section M1502.4.5.1
Length Identification. Where the exhaust duct equivalent length exceeds 35 feet, the equivalent length shall
be identified on a permanent label or tag located within 6 feet of the exhaust duct connection. Section
M1502.4.6
Makeup Air. Installations exhausting more than 200cfm shall be provided with makeup air. Where a closet is
designed for the installation of a clothes dryer, an opening having an area of not less than 100 square inches
shall be provided in the closet enclosure. Section M1502.7
116. Domestic cooking equipment shall be provided with exhaust equipment with a minimum intermittent rate of 150cfm
in accordance with Section M1503. Where installations exhaust more than 400cfm, makeup air shall be provided in
accordance with Section M1503.6.
117. Rooms with toilet, bathing, and spa facilities. Toilet rooms and compartments with less than 1.5sf of window opening,
and all rooms with bathing or spa facilities, shall be mechanically ventilated. The minimum mechanical ventilation rate
for toilet rooms is 50cfm. Ventilation systems serving bathing or spa facilities shall be controlled by a dehumidistat,
timer or similar means of automatic control, with a minimum rate of 80cfm intermittent or 20cfm continuous. Sections
R303.3, M1505, and M1507
118. Whole-house mechanical ventilation is required for all new dwelling units, and shall be designed to provide outdoor
air at a minimum rate based on the dwelling’s floor area and number of bedrooms in accordance with M1505.4. Sections
R303.4 and M1505.4
CLACKAMAS COUNTY – 2021 RESIDENTIAL CODE SUMMARY
Oregon codes are available for viewing online at: Oregon.gov/bcd. CCP-PW29 (Rev. 11/21)
119. Combustion air. Solid fuel-burning appliances shall be provided with combustion air in accordance with installation
instructions by the appliance manufacturer. Oil-fired appliances shall be provided with combustion air in accordance
with NFPA 31. The requirements for combustion and dilution air for gas-fired appliances shall be in accordance with
Chapter 24. Section M1701.1
120. Radon mitigation is required for new dwellings within Clackamas County. Refer to ORSC Appendix F for radon mitigation
requirements.
Energy Efficiency
121. New construction. All conditioned spaces within new habitable buildings shall comply with the prescriptive
requirements of Table N1101.1(1) and one additional measure from Table N1101.1(2).
Exception: Conditioned, non-habitable, detached accessory structures shall meet the following requirements
without additional measures: R-21 walls, R-38 attic or R-20 continuous roof (above deck), U-0.35 windows, U-
0.70 opaque doors, and U-0.50 roll-up doors.
Table N1101.1(1) - Prescriptive Envelope Requirements
(* Simplified version - Refer to the entire table for footnotes and complete requirements)
Building Component Standard Base Case
Required Performance Equiv. Value *
Wall insulation - above grade U-0.059 * R21 Intermediate *
Wall insulation - below grade * C-0.063 R-15/R-21
Flat ceilings * U-0.021 R-49
Vaulted Ceilings * U-0.033 R-30 Rafter or R-30A * Scissor Truss
Underfloors U-0.033 R-30
Slab edge perimeter F-0.520 R-15
Heated slab interior * n/a R-10
Windows * U-0.027 U-0.027
Skylights * U-0.050 U-0.050
Exterior doors * U-0.020 U-0.020
Exterior doors with > 2.5 sq. ft. glazing *
U-0.040 U-0.040
122. Alterations and repairs affecting energy conservation measures, and alterations or repairs which affect components of
existing conditioned spaces, shall comply with Table N1101.1.
Exception: The minimum component requirements may be used to the maximum extent practical.
Table N1101.2 - Existing Building Components Requirements
(* Simplified version - Refer to the entire table for footnotes and complete requirements)
Building Component Standard Base Case
Required Performance
Equiv. Value *
Wall insulation U-0.083 R-15
Flat ceiling U-0.025 R-49
Vaulted Ceilings > 10 inches nominal rafter depth
U-0.040 R-25
Vaulted Ceilings > 8 inches nominal rafter depth U-0.047 R-21
Underfloor > 10 inches nominal joist depth U-0.028 R-30
Underfloor > 8 inches nominal joist depth U-0.039 R-25
Slab edge perimeter F-0.52 R-15
Windows U-0.030 U-0.030
Skylights U-0.060 U-0.060
Exterior doors U-0.020 R-5
Exterior doors with > 2.5 sq. ft. glazing U-0.040 R-2.5
Forced air ducts n/a R-8
CLACKAMAS COUNTY – 2021 RESIDENTIAL CODE SUMMARY
Oregon codes are available for viewing online at: Oregon.gov/bcd. CCP-PW29 (Rev. 11/21)
123. Change of occupancy or use. Existing, unconditioned spaces such as garages and basements, and newly enclosed spaces
such as porches or canopies that are to become conditioned spaces, shall comply with Section N1101.2.3. Where no
changes are made to existing building components, such buildings may comply with Table N1101.2 to the greatest
extent practical. Changes in use that are greater than 30% of an existing building’s heated floor area or more than 400sf
(whichever is less) shall be required to comply with one measure from Table N1101.3.
124. Additions to existing buildings or structures may be made without making the entire building or structure comply with
current energy requirements, if the new additions comply with such requirements.
Large additions. Additions that are 600 square feet in area or more shall be required to comply with Table
N1101.1(2).
Small additions. Additions that are less than 600 square feet in area shall be required to select one measure
from table N1101.1(2) or comply with Table N1101.3.
Exception: Additions that are less than 225sf shall not be required to comply with Table N1101.1(2)
or Table N1101.3.
125. Insulation materials. Insulation materials shall be installed per manufacturer's listing and specifications and this section.
Insulation R-values shall be specified as required in 16 CFR Ch. I (1-1-91 Edition) Part 460-Labeling and Advertising of
Home Insulation. Some general requirements for insulation are:
Loose-fill insulation. Blown, poured and spray-on type insulation complying with Section R316 may be used in
attic spaces where roof slope is 4 units vertical in 12 units horizontal (33.3 percent slope) or greater and there
is at least 44 inches (1 118 mm) of headroom at the roof ridge. (Clear headroom is defined as the distance from
the top of the bottom chord of the truss or ceiling joists to the underside of the roof sheathing.) Adequate
baffling of the vent opening shall be provided so as to deflect the incoming air above the surface of the blown
or poured insulation. Baffles shall be of weather-resistant, rigid material capable of retaining the insulation and
shall be in place at the time of framing inspection. Section N1104.2
Batt-type insulation. Batt-type insulation shall be installed flush against the warm side of the cavity insofar as
practicable. Section N1104.2.2
Foam plastic materials shall meet the general and application-specific requirements provided within Section
R316.
Insulation protection. Insulation exposed to the exterior shall be protected from physical and solar damage.
Section N1104.2.3
Clearances. Recessed light fixtures shall be IC labeled for direct insulation contact. Thermal insulation shall not
be installed within 3 inches (76 2. mm) of any metal chimney or gas vent that is not listed for insulation
clearances. Thermal insulation shall not be installed in a manner that would obstruct openings required for
attic ventilation. A permanent sleeve of fine wire mesh screen, sheet metal or other noncombustible material
shall be installed to maintain the required clearances. Section N1104.2.4
Fire Safety. All exposed insulation materials, including facings, shall have a flame-spread index not to exceed
25 with an accompanying smoke developed index not to exceed 450 when tested in accordance with ASTM
E84 or UL 723. See Section R302.10 complete requirements and possible exceptions.
126. Slab-on-grade floors. For slab-on-grade floors, the perimeter of the floor shall be insulated. The insulation shall extend
downward from the top of the slab for a minimum of 24 inches or downward to the bottom of the slab, then horizontally
beneath the slab for a minimum total distance of 24 inches. Section N1104.7
Exception: For monolithic slabs, the insulation shall extend downward from the top of the slab to the bottom
of the thickened edge.
Slab-on-grade floors with hydronic heat. For slab-on-grade floors that incorporate hydronic heating, in
addition to perimeter insulation, the entire underside of slab shall be insulated to R-10. Section N1104.7.1
127. Air Barriers. An air barrier shall be installed and fully aligned with the thermal envelope on every vertical portion of air-
permeable insulation and on the warm side of horizontal, air-permeable insulation. Section N1104.8.1
Exception: Unvented attics, continuous insulation walls and similar conditions where an impermeable
insulation layer forms an air barrier.
128. Sealing required. Exterior joints around window and doorframes, between wall cavities and windows or door frames,
between wall and foundation, between wall and roof, between wall panels, at penetrations of utility services through
walls, floors and roofs and all other openings in the exterior envelope shall be sealed in a manner approved by the
building official. Sealing for the purpose of creating a continuous air barrier shall be in accordance with Table N1104.8,
or the dwelling shall be tested to demonstrate a blower door result of not greater than 4.0ACH50. Section N1104.8.2
Top plate sealing is required at all walls in contact with ventilated attics, using caulk, sealant, gasket, or other
approved material. Section N1104.8.2.1
129. Vapor retarders. A Class II vapor retarder (less than 1.0 perms) shall be installed on the warm side (in winter) of all
insulation. Sections R318 and N1104.9.1
Exceptions:
1. In construction where moisture or freezing will not damage the materials.
2. Where the framed cavity or space is ventilated to allow moisture to escape.
CLACKAMAS COUNTY – 2021 RESIDENTIAL CODE SUMMARY
Oregon codes are available for viewing online at: Oregon.gov/bcd. CCP-PW29 (Rev. 11/21)
3. Class III vapor retarders (less than 10.0 perms) shall be permitted for framed walls where either of the
following apply:
Vented cladding is installed over wood structural panels.
Continuous air permeable insulation is applied on exterior above-grade wall surfaces.
130. Ground cover. A ground cover shall be installed in the crawl space for both new and existing buildings when insulation
is installed. Ground cover shall be 6-mil (0.15 mm) black polyethylene or other approved material of equivalent perm
rating. Ground cover shall be lapped 12 inches (305 mm) at all joints and cover the entire surface area extending full
width and length of the crawl space and turn 12 inches (305 mm) up the foundation wall. Ground cover of 6-mil (0.15
mm) polyethylene or an approved equal (that is as durable) shall be installed on the ground beneath concrete floor
slabs located in conditioned spaces. Section N1104.9.2
131. High-efficiency lighting. All permanently installed lighting fixtures shall be high-efficiency light sources. Screw-in
compact florescent lamps comply with this requirement. The building official shall be notified in writing at the final
inspection that the permanently installed lighting fixtures have met this requirement. Sections N1107.2 and N1107.3
Exception: High-efficacy lamps are not required at 2 indoor and 2 outdoor fixtures.
Renewable Energy and Energy Storage
132. Solar interconnection pathway. A 4 inch square metal junction box and cover is required within 24" of the main
electrical panel, with a 3/4 inch (minimum) rigid metal raceway (or #10 copper 3-wire MC cable w/ 6" min. free end)
from J-box to a capped roof termination (or to an accessible attic location in the attic with 36" minimum vertical
clearance, terminating 6" minimum above insulation). The end shall be marked: “RESERVED FOR SOLAR”. Section
N1107.4
133. Solar thermal energy systems shall be designed and installed in accordance with Chapter 23. Section R324.2
134. Rooftop photovoltaic systems shall be designed in accordance with Section 3111 of the Oregon Structural Specialty
Code (OSSC). Firefighter pathways shall be provided in accordance with OSSC Section 3111.3.4.8.1. Prescriptive
installations must comply with OSSC Section 3111.3.5.3, including (but not limited to) module/racking attachment
spacing not greater than 4 feet on center (2 feet on center maximum where located within 3 feet of a roof edge, hip,
eave, or ridge, or at locations where the ground snow load exceeds 26psf). Section R324.3
135. Stationary storage battery systems shall be listed and labeled for residential use in accordance with UL 9540 (inverters
in accordance with UL 1741 or provided as part of the system’s listing), and shall be installed in accordance with mfr.
installation instructions, the UL listing, and the Electrical Code. Such systems shall not be located within the habitable
space of a dwelling unit, shall be provided with impact protection where subject to vehicle damage, and shall be
provided with ventilation in accordance with Section M1307.4 where hydrogen or other flammable gases are produced
during charging. Section R330
Exceptions to listing requirements:
1. Where approved, repurposed unlisted battery systems from electric vehicles are allowed to be
installed outdoors or in detached sheds located not less than 5 feet from exterior walls, property lines
and public ways.
2. Battery systems that are an integral part of an electric vehicle are allowed provided that the
installation complies with Section 625.48 of the Electrical Code.
3. Battery systems less than 1 kWh (3.6 megajoules).
