The amendments to the 2018 International Residential Code are listed hereafter by section. The last digits of the number (after the title and chapter digits) are the section of the 2018 International Residential Code to which the amendments refer, i.e., 23.85.R310 refers to amendments to Section R310 of the 2018 International Residential Code.
(AO No. 2020-85, § 1, 10-27-2020)
Revise Section 101.2 to read as follows:
The provisions of this code shall apply to the construction, alteration, movement, enlargement, replacement, repair, equipment, use and occupancy, location, removal and demolition of detached one-, two- and three-family dwellings and townhouses not more than three stories above grade plane in height with a separate means of egress and their accessory structures not more than three stories above grade plane in height.
Exception: The following shall be permitted to be constructed in accordance with this code where provided with a residential fire sprinkler system approved by the fire code official:
1.
Live/work units located in townhouses and complying with the requirements of Section 419 of the International Building Code.
2.
Owner-occupied lodging houses with five or fewer guest rooms.
3.
A care facility with five or fewer persons receiving custodial care within a dwelling unit.
4.
A care facility with five or fewer persons receiving medical care within a dwelling unit.
5.
A care facility with five or fewer persons receiving care that are within a single-family dwelling.
(Ord. No. 2023-130(S), § 7, 1-16-2024)
Add the following information to Table R301.2(1):
Ground snow load
50 PSF - Equates to 40 psf roof snow load
Wind Speed
See 23.85. Figure R301.2(5)A
Topographic effects
Per site
Special Wind Region
Per site
Windborne Debris Zone
No
Seismic Design Category
D 2
Subject to damage from: Weathering
Yes, severe
Frost Line Depth
42" for warm foundation, 60" for cold foundation
Termite
No
Winter Design Temperature
-7 Degrees
Note this ASHRAE 99% design temperature may not be appropriate for all areas within the MOA.
Ice Barrier Underlayment Required
Yes
Flood Hazards
Yes, see flood hazard maps
Air Freezing Index
3500
Mean Annual Temperature
35°F
Manual J Design Criteria:
Elevation
Less than 1,000 ft.
Latitude
61 Degrees N
Winter Heating
-7 Degrees (ASHRAE 99%)
Summer Cooling
72 Degrees
Altitude correction factor
1.0
Indoor design temperature
70 Degrees
Heating temperature difference
84 Degrees
Wind Velocity heating
15
Wind velocity cooling
7.5
Coincident wet bulb
58 Degrees
Daily range
M
(AO No. 2020-85, § 1, 10-27-2020)
A. 
Amend the first paragraph by deleting, "where wind design is required in accordance with Figure R301.2(5)B", and replace with, "where the ultimate wind speeds are equal to or exceed 145 mph per Figure 23.85. Figure R301.2(5)A.
B. 
Under exceptions add exception 4:
4.
Single story accessory structures 600 square feet or less in gross floor area.
C. 
Amend paragraph after exceptions by deleting: "In regions where wind design is required in accordance with Figure R301.2(5)B," and replace with "Where the ultimate wind speeds are equal to or exceeds 145 mph per figure 23.85. Figure R301.2(5)A,".
(AO No. 2020-85, § 1, 10-27-2020)
Add the following subsections:
R302.2.3.1 Horizontal continuity. The fire resistance rated dwelling unit separation wall or walls shall be continuous from exterior wall to exterior wall and shall terminate at the interior surface of the exterior sheathing or siding.
R302.2.3.2 Exterior walls. Where the fire resistance rated wall assembly separating townhouses intersects the exterior wall, an (assumed) imaginary lot line shall extend outward from the intersection. The location of the imaginary lot line in relation to the exterior walls shall be such that the exterior wall fire resistance rating and opening protection meet the requirements set forth in section R302.1. Where the exterior walls on each side of the townhouse's separation walls form an angle equal to or greater than 180 degrees, exterior wall and opening protection is not required.
R302.2.3.3 Horizontal projecting elements. The fire resistance rated dwelling unit separation wall or walls shall extend to the outer edge of horizontal projecting elements such as balconies, roof overhangs, canopies, marquees, and similar projections that are within 4 feet of the separation wall.
Exceptions:
1.
Horizontal projecting elements without concealed spaces.
2.
Noncombustible horizontal projecting elements.
(AO No. 2020-85, § 1, 10-27-2020)
Add the following section:
R302.2.7 Common wall insulation. The dwelling unit separation wall shall be fire blocked at ceiling line and insulated in the attic directly above the fire blocking to the minimum required attic R-value.
(AO No. 2020-85, § 1, 10-27-2020)
A. 
Amend the first sentence by replacing "in two-family dwellings" with "in two-family and three-unit dwellings".
B. 
Add to the end of the paragraph:
A detached single family or two-family dwelling unit with an ADU (Accessory Dwelling Unit) is considered to be a two-family or three-unit dwelling, as the case may be, unless the ADU communicates freely with the single-family or one of the two-family dwelling units.
C. 
Add the following section:
R302.3.2 Common wall insulation. The dwelling unit separation wall shall be fireblocked at ceiling line and insulated in the attic directly above the fireblocking to the minimum required attic R-value.
(AO No. 2020-85, § 1, 10-27-2020; AO No. 2023-130(S), § 8, 1-16-2024)
Add to the end of the paragraph:
Doors shall have smoke gaskets along the top and sides and an adjustable threshold or sweep. Access from a garage to the crawlspace shall be in a wall and not through the floor. Access from a garage to the crawlspace shall be protected in accordance with this section.
(AO No. 2020-85, § 1, 10-27-2020)
Add the following sentence to the end of exception 2:
Direct vent, sealed-combustion fuel fired appliances shall be allowed without floor protection.
(AO No. 2020-85, § 1, 10-27-2020)
Add exception #4 as follows:
4.
Theater rooms are exempt from the ventilation requirements of this section.
(AO No. 2020-85, § 1, 10-27-2020)
Add the following sentence to end of paragraph:
In lieu of labels adhered to skylights, literature provided on site is acceptable to demonstrate skylights meet the criteria of this section.
(AO No. 2020-85, § 1, 10-27-2020)
Add exception #3 as follows:
3.
Where windows are provided as a means of escape or rescue in a basement, the sill height shall be measured from the finished floor to the bottom of the clear opening and shall be no more than 48 inches above the finished floor.
(AO No. 2020-85, § 1, 10-27-2020)
Delete the text in section R313 and replace with the following:
The installation of a fire sprinkler system requires a fire systems permit in accordance with the International Fire Code.
(AO No. 2020-85, § 1, 10-27-2020)
A. 
Amend first sentence by deleting the words "naturally durable wood or".
B. 
Add the following sentence to the end of item number 5:
Measures should be taken to mitigate frost heaving if wood siding or sheathing has less than six-inch clearance.
(AO No. 2020-85, § 1, 10-27-2020)
Add the following sentence to the end of the paragraph:
This requirement only applies to exposed glue-laminated timbers in section R317.1.5 and AWW foundation walls.
(AO No. 2020-85, § 1, 10-27-2020)
Add the following exception:
4.
Roof access, pathways and setback requirements do not apply to photovoltaic systems installed on a single roof plane of a building having multiple roof planes where such roof plane is not located below or provides access to an emergency escape and rescue opening.
(AO No. 2020-85, § 1, 10-27-2020)
Amend Chapter 3 by adding the following section:
SECTION R328 MOISTURE CONTROL IN INSULATED ASSEMBLIES
R328.1 Moisture control strategies. The building design shall incorporate both interior and exterior moisture control strategies to prevent the accumulation of moisture within insulated assemblies. Exterior moisture control shall comply with Chapters 7 and 9. Interior moisture control shall comply with section R328.1.1. Should insulated assemblies become wet or start out wet, the design strategy shall allow the assembly to dry to either the exterior or interior. Materials shall be allowed to dry prior to enclosure.
R328.1.1 Interior moisture control in insulated assemblies. Methods to control moisture accumulation within insulated assemblies from the building interior shall address both vapor diffusion and air leakage. Vapor diffusion shall be controlled by the installation of a class I or class II vapor retarder on the warm-in-winter side of the insulation. The vapor retarder shall be continuous, and seams shall be lapped 6 inches minimum. Penetrations and seams shall be sealed with approved vapor retarder compatible tape or sealant to control air leakage. Where a vapor retarder is located in dropped ceilings adjacent to attics, the vapor retarder continuity shall be maintained above the dropped ceiling and shall be fully covered with a solid material such as gypsum wallboard, plywood, oriented strand board or other similar material.
Exceptions:
1.
A vapor retarder is not required in construction where moisture or its freezing will not damage materials.
2.
A vapor retarder is not required on crawlspace walls designed to dry to the interior.
3.
A vapor retarder is not required on basement walls designed to dry to the interior. Such walls shall be insulated with one of the following methods:
 
a.
Two inches minimum of EPS or XPS foam plastic insulation applied directly against the exterior of the foundation wall, and one inch of EPS, XPS or polyisocyanurate (PIR) applied between the interior surface of the foundation wall and framing. The framing cavity may be insulated with any type of approved insulation.
 
b.
Three inches minimum of two-pound density closed cell foam plastic insulation applied to the interior side of the foundation wall with one inch minimum of insulation between any wall framing and the foundation wall.
 
c.
Four inches minimum of EPS or XPS foam plastic insulation applied directly against the exterior of the foundation wall.
 
d.
Equivalent moisture resistant system approved by the building official.
4.
A vapor retarder is not required at cantilevered floor assemblies where the floor decking consists of nominal ¾ inch plywood, OSB or other approved material having a perm rating meeting the class II requirements. Joints shall be sealed.
5.
The rim joist does not require a vapor retarder.
6.
Notwithstanding exception 3a, up to one-third of the total installed insulation R-value may be installed on the warm side of the vapor retarder. This exception applies only when the daily average indoor relative humidity is maintained below 35 percent during the heating months of November through March.
7.
A class III vapor retarder may be used on walls and roof insulated to a minimum value of R-21 with spray foam having a minimum density of 2 pounds per cubic foot.
(AO No. 2020-85, § 1, 10-27-2020)
Add the following situation to the exception:
3.
Repair of wood foundations with a crawlspace shall be per 23.85. Figure R403-34.
(AO No. 2020-85, § 1, 10-27-2020)
Add the following sentence to the end of the paragraph:
There shall not be a net increase in surface drainage across property lines. Approved discharge locations shall include street gutters, drainage easements, ditches, or other approved locations. Surface runoff may be retained on site or follow existing drainage patterns to prevent adverse impact to neighboring properties.
(AO No. 2020-85, § 1, 10-27-2020)
Add the following subsection:
R401.4.3 Areas of high and very high Seismically induced ground failure susceptibility. The construction of a dwelling or accessory structure in seismically induced ground failure zones 4 or 5 (as delineated on the Municipality of Anchorage, Geotechnical Hazard Assessment Map) requires a site-specific geotechnical investigation in accordance with section 1803 of the 2018 IBC. The site-specific geotechnical investigation shall be prepared by a professional civil engineer, qualified in the field of Geotechnical Engineering, registered in the State of Alaska. The structure shall be designed and sealed by a structural engineer registered in the State of Alaska.
Exceptions:
1.
A geotechnical report is not required for an addition to a detached single-family residence or duplex where all the following conditions apply:
a.
The footprint of the addition does not exceed the footprint of the existing building;
b.
The addition does not increase or exceed the number of stories of the existing building; and
c.
Structural analysis demonstrates that new foundation elements can match existing.
2.
A geotechnical report is not required for a detached accessory structure less than 400 square feet in area.
3.
Unless required by a plat note, a registered engineer does not need to design either the structure or its foundation if the geotechnical report is based on site-specific soils information where all the following are true:
a.
Slope Stability: A submitted pseudo-static slope stability analysis has a minimum factor of safety of at least 1.10 for seismic loading conditions in accordance with AMC Section 23.15.1803.5.11.
b.
Liquefaction: The potential for liquefaction and soil strength loss evaluated in terms of peak ground acceleration, earthquake magnitude, and duration is unlikely.
c.
Lateral Spreading and Pressure Ridges: The potential for earthquake induced lateral spreading and pressure ridges is unlikely.
(AO No. 2020-85, § 1, 10-27-2020)
Add the following:
Wood foundations are not allowed on new construction. Repair of existing wood foundations shall be in accordance with this code.
(AO No. 2020-85, § 1, 10-27-2020)
Replace R403.1 through R403.1.3.6 and associated figures and Tables with the following:
1.
Definitions:
 
a.
WARM FOUNDATION: Any foundation where the temperature of the bearing soils is normally maintained above freezing;
 
b.
COLD FOUNDATION: Any foundation where the temperature of the bearing soils is normally subjected to freezing.
2.
Foundations shall be constructed as shown in Table 23.85.R403-16 and Figures 23.85.R403-25, 23.85.R403-29, 23.85.R403-31, 23.85.R403-34 (repair only), and 23.85.R403-37 or foundations shall be designed under the provisions of the IBC. Footings and foundations shall be constructed of masonry or concrete. Footings of concrete and masonry shall be of solid material. Foundations supporting wood shall extend at least 6 inches above the adjacent grade. Unless other recommendations are provided by a foundation investigation report, footings shall meet the following requirements:
 
a.
Minimum footing depths shall be indicated in 23.85. Table R403.1. Footings shall bear on undisturbed natural inorganic soil, or suitably compacted fill.
 
b.
Cast-in place concrete piers shall be founded at a depth suitable for structural support or as indicated in 23.85. Table R403.1, whichever is greater. Connecting grade beams between piers on perimeter walls of warm buildings shall extend at least 36 inches below ground surface and shall be protected from frost heave. The potential for frost heave below grade beams of cold structure shall be accounted for in the design of these elements.
 
c.
All reinforcement in foundation walls shall be grade 60.
 
d.
All masonry shall be solid grout, Type M or S Mortar and mechanically consolidated.
(AO No. 2020-85, § 1, 10-27-2020)
1.
Reinforced concrete walls shall be anchored to all floors and roofs in accordance with section 1604.8.2 of the International Building Code.
2.
All intersecting reinforced concrete walls shall be tied together. (ACI 318-14; 11.2.4.1)
3.
All interior and exterior concrete walls shall be reinforced. Minimum yield strength - Grade 60. (ACI 318-14; 11.6)
4.
All structural members framing into or supported on concrete walls or columns shall be anchored. (ASCE 7-16; 1211)
5.
All deformed reinforcing bars shall meet or exceed one of the listed ASTM requirements. (ACI 318-14; 20.2.1.3)
6.
Concrete in seismic zone D shall have a minimum compressive strength of 3000 psi for severe exposure. (See IBC 1808.8.6; ACI 318-14; table 19.3.2.1)
7.
The following minimum reinforcement requirements shall apply to all below grade concrete walls (i.e. basement walls and crawlspace walls). This reinforcing does not apply to above grade walls, which must be designed in accordance with the requirements of IBC.
MINIMUM REINFORCEMENT FOR CONCRETE WALLS
(Horizontal and Vertical Spacing)
Width of Wall
#5 Bar
#4 Bar
6" Walls
#5 @ 18" O.C. hor.
#4 @ 16" O.C. hor.
#5 @ 18" O.C. vert.
#4 @ 18" O.C. vert.
8" Walls
#5 @ 18" O.C. hor.
#4 @ 12" O.C. hor.
#5 @ 18" O.C. vert.
#4 @ 18" O.C. vert.
10" Walls
#5 @ 15" O.C. hor.
#4 @ 10" O.C. hor.
#5 @ 18" O.C. vert.
#4 @ 16" O.C. vert.
(AO No. 2020-85, § 1, 10-27-2020)
Foundation Type
Minimum Footing Depth (Inches)
Warm Foundation
 
Cold Foundation (3), (4)
Perimeter Footing (1)
42
All measurements are from top of finished grade
60
Interior or Interior Isolated Spread Footings (2)
60
Cast-in-Place Concrete Pier
42
120 (5)
NOTES TO TABLE:
(1)
Dimension indicated is from bottom of footing to adjacent exterior grade. Basements or crawlspace walls supporting more than five feet differential fill on opposite faces shall be restrained as necessary against lateral movement.
(2)
Dimension indicated is from bottom of footing to nearest adjacent grade.
(3)
Exterior landings, that are not the primary entrance, and not attached to the building, and not larger than 50 square feet and not greater than 72 inches above grade may be supported on near surface pier blocks founded on adequate soils. Bearing materials shall meet the other provisions of this code. The potential for and the effects of frost heave shall be considered.
(4)
The minimum footing depths may not be adequate for frost susceptible soils. Cold footings shall be founded below the frost line or be protected from freezing with insulation or other appropriate means. In addition, provisions shall be made to resist uplift forces due to frost jacking on the side of cold foundations.
(5)
Cast-in-place concrete piers installed in non-frost-susceptible material may be 60 inches.
(AO No. 2020-85, § 1, 10-27-2020)
Delete paragraph and replace with the following:
Wood foundations are not allowed on new construction. Repair of wood foundations shall be in accordance with 23.85. Figure R403-34.
(AO No. 2020-85, § 1, 10-27-2020)
A. 
Amend footnote (c) as follows:
c.
Insulation shall be expanded polystyrene (EPS) or extruded polystyrene (XPS) manufactured in accordance with ASTM C578. The following R-values shall be used to determine insulation thickness required for this application:
 
i.
Type II EPS: R-3.2 per inch vertical and R-2.6 per inch horizontal;
 
ii.
Type IX EPS: R-3.4 per inch vertical and R-2.8 per inch horizontal;
 
iii.
Type X, IV, VI, VII and V XPS: R-4.5 per inch vertical and R-4.0 per inch horizontal.
 
For EPS insulation Types not listed, the R-value used to determine insulation thickness shall be 80 percent of the manufacturer listed R-value @75F for vertical insulation and 67 percent of the manufacturer listed R-value @75F for horizontal insulation. Reference ASCE Standard 32-01, Appendix A.
B. 
Delete footnotes (d) and (e).
(AO No. 2020-85, § 1, 10-27-2020)
Delete section R404.2. Wood foundations are not allowed on new construction. Existing wood foundations shall be repaired in accordance with 23.85. Figure R403-34 All Weather Wood Foundation.
(AO No. 2020-85, § 1, 10-27-2020)
Delete paragraph and substitute with the following:
Wood sill plates shall be minimum 2-inch by 6-inch and shall be bolted to the foundation or foundation wall with not less than 10-inch by ½-inch nominal diameter galvanized steel bolts embedded at least 7 inches into the concrete or in fully grouted cells of reinforced masonry and spaced not more than 6-feet apart. There shall be a minimum of two bolts per piece with one bolt located within 12 inches of each end of each piece. Wood sill plates must be a treated material specified in Section R317.1.
(AO No. 2020-85, § 1, 10-27-2020)
A. 
In the first sentence beginning with the word "enclose", replace the wording in the rest of the sentence with the following: "crawl space walls 40 inches or less in height shall be damp-proofed from above grade to 6 inches below the top of the footing."
B. 
Add exception #2 as follows:
2.
Foundation walls backfilled on both sides, such as those used in conjunction with a "slab on grade", do not require damp-proofing.
(AO No. 2020-85, § 1, 10-27-2020)
A. 
Replace the first sentence with the following:
Exterior foundation walls that retain earth and enclose habitable or usable interior spaces and floors below grade shall be waterproofed from above grade to 6 inches below the top of the footing.
B. 
Add exception #2 as follows:
2.
Foundation walls backfilled on both sides, such as those used in conjunction with a "slab on grade" do not require waterproofing.
(AO No. 2020-85, § 1, 10-27-2020)
Revise R406.3.2 to read as follows:
Approved waterproofing shall be applied over the below-grade portion of exterior basement and crawlspace walls prior to backfilling. A treated lumber or plywood strip shall be attached to the wall to cover the top edge of the approved waterproofing. The wood strip shall extend at least two inches above and five inches below finish grade level to protect the approved waterproofing from exposure to light and from mechanical damage at or near grade. The joint between the strip and the wall shall be caulked full length prior to fastening the strip to the wall. Alternatively, brick, stucco, or other covering appropriate to the architectural treatment may be used in place of the wood strip. The approved waterproofing shall extend down from above grade to six inches below the top of the footing.
(AO No. 2020-85, § 1, 10-27-2020)
Replace paragraph with the following:
Exterior surface of steel columns exposed to the elements shall be protected with a rust inhibitive paint, except for corrosive-resistant steel and steel treated with coatings to provide corrosion resistance.
(AO No. 2020-85, § 1, 10-27-2020)
Amend section by adding item 3 as follows:
3.
All studs in walls containing plumbing drains and vents shall be a minimum of 6-inch nominal width or structurally sheath one side when 4-inch nominal width studs are used.
(AO No. 2020-85, § 1, 10-27-2020)
A. 
Amend the first sentence by starting the sentence with:
"Though not required by the Municipality of Anchorage, when installed or when required by the exterior wall covering manufacturer, apply…".
B. 
Amend the first sentence by adding the word "permeable" between the "of" and "No. 15".
(AO No. 2020-85, § 1, 10-27-2020)
Renumber item 1.3 to 1.4 and add 1.3 as follows:
1.3.
Where flashing cannot be installed per one of the above referenced methods, the exterior opening shall be caulked and sealed with exterior grade, paintable caulk, a minimum of a ⅜-inch bead.
(AO No. 2020-85, § 1, 10-27-2020)
Add the following to the end of the paragraph:
Exterior type plywood siding with a grooved pattern shall not be installed horizontally and used as the weather resistant siding.
(AO No. 2020-85, § 1, 10-27-2020)
Add a sentence to end of paragraph as follows:
The minimum depth from the roof sheathing to the wall top plate at exterior side of the exterior wall shall be 11¼ inches.
(AO No. 2020-85, § 1, 10-27-2020)
Add the following sentence to end of paragraph:
Minimum depth of truss at exterior wall plate shall be 11¼ inches at exterior side plate.
(AO No. 2020-85, § 1, 10-27-2020)
Amend section R802 by adding the following section:
R802.12 Wood frame roof attachment at eave blocking. The following 5 options are an acceptable means for transferring roof diaphragm shear forces to exterior walls. Alternative designs based on calculations for shear transfer to the exterior walls may be used in lieu of these details. Regardless of the method selected, roof ventilation shall comply with section R806.
OPTION 1
Full-height blocking in every truss space with 3 or more 2-inch diameter or larger holes located near the top of block.
OPTION 2
Full-height blocking in every other truss space with 3 or more 2-inch diameter or larger holes located near the top of block, with partial height blocking in alternate spaces. Partial height blocking shall allow a clear air gap of between 1½ to 2 inches. Minimum size partial height block is 2×10 where truss heels are 11¼ inches high.
OPTION 3
This partial height blocking configuration may be used where trusses have of 11¼ inch heels at the wall line. Blocking is required in every truss space.
OPTION 4
This partial height blocking configuration may be used where diaphragm shear is less than 95 plf. Blocking is required in every truss space.
OPTION 5
For prescriptively braced wall panels and engineered shear wall designs for one- and two-family dwellings and townhomes, this configuration, as described in R602.10.8.2.2, may be used.
(AO No. 2020-85, § 1, 10-27-2020)
Add the following to the end of the paragraph:
At least 50 percent and not more than 80 percent of the required ventilating area shall be provided by ventilators located in the upper portion of the space. Upper ventilators shall be located no more than 3 feet below the ridge or highest point of the space, measured vertically, with the balance of the required ventilation provided at the eaves. Where the location of wall or roof framing members conflicts with the installation of the upper ventilators, installation more than 3 feet below the ridge or highest point of the space shall be permitted.
(AO No. 2020-85, § 1, 10-27-2020)
Add the following to Section:
Attic access shall not be located in a room containing bathing facilities. Access may be located in closets with minimum depth of 23 inches and minimum width of 48 inches.
(AO No. 2020-85, § 1, 10-27-2020)
Add the following to the end of section:
1.
All valleys shall have a modified bitumen ice barrier lapped eighteen inches minimum each side of valley centerline. No penetrations shall be located in required valley ice barrier.
2.
All roof penetrations shall be located a minimum of six feet from valley centerline and four feet from the exterior wall line at the eave measured on a horizontal plane, excluding attic ventilation.
3.
All roof penetrations shall extend above the roof surface a minimum of 24 inches, except attic ventilation.
4.
Type B gas vents may penetrate the eave ice barrier area if installed within 24 inches, wood framed, R-19 insulated curb, measured on the ridge side of the roof. The ice barrier must extend up the curb a minimum of 12 inches on all sides. See detail below.
(AO No. 2020-85, § 1, 10-27-2020)
Delete sections and tables and replace with the following:
Underlayment shall comply with ASTM D 226 Type I (No. 15 Asphalt Felt). For slopes 4V:12H and steeper underlayment shall be at least one layer installed with a 4-inch lap over the ice barrier. Each subsequent layer shall be lapped 4 inches vertically and two inches horizontally to shed water, continuing to the ridge, fastened sufficiently to hold in place.
(AO No. 2020-85, § 1, 10-27-2020)
Replace section with the following:
An ice barrier shall be a self-adhering polymer modified bitumen sheet complying with ASTM D 1970. For slopes less steep than, but not including, 4V:12H, an ice barrier shall be used over the entire surface of the roof. No additional normal underlayment is required. For slopes 4V:12H and steeper an ice barrier shall extend from the lowest edges of all roof surfaces to a point at least 36 inches inside the exterior wall line of the building. The remainder of the roof surfaces may be covered with underlayment per 23.85.R905.1.1.
(AO No. 2020-85, § 1, 10-27-2020)
Replace items 1, 2, and 3 with the following:
1.
For open valleys (valley lining exposed) lined with metal, the valley lining shall be not less than 24 inches wide and of any of the corrosion-resistant metals in table R905.2.8.2 installed over the required 36-inch wide self-adhering polymer modified bitumen underlayment complying with ASTM D 1970.
2.
For open valleys (valley lining exposed) lined with one ply of mineral-surfaced roll roofing, complying with ASTM D 3909 or ASTM D 6380 Class M, 36" wide installed over the required 36" wide self-adhered polymer modified bitumen underlayment complying with ASTM D 1970.
3.
For closed valleys (valley covered with shingles), valley lining of one layer of self-adhered polymer modified bitumen underlayment, minimum 36" wide, complying with ASTM D 1970 shall be permitted.
(AO No. 2020-85, § 1, 10-27-2020)
Add the following exception:
Exception: A 1x drip edge installed at the top of the fascia shall be permitted where the roof shingles overhang the 1x at least 1-inch.
(AO No. 2020-85, § 1, 10-27-2020)
Delete the words:
"except for coal-tar built-up roofs, which shall have a design slope of a minimum one-eighth unit vertical in 12 units horizontal (1-percent slope)."
(AO No. 2020-85, § 1, 10-27-2020)
Add to the end of the paragraph:
If the manufacture recommendations does not require a clearance from insulation, an insulation thimble is not required.
(AO No. 2020-85, § 1, 10-27-2020)
Add the following terms:
AHFC. Alaska Housing Finance Corporation.
AK HERS Guidelines. AHFC Alaska Home Energy Rating System Guidelines.
AKWarm. AHFC approved home energy rating system computer-simulation software.
ASHRAE. The American Society of Heating, Refrigerating and Air-Conditioning Engineers.
BEES. AHFC Building Energy Efficiency Standard, established by the State of Alaska. BEES is comprised of the 2018 International Energy Conservation Code, ASHRAE Standard 62.2 2016, and the Alaska Specific Amendments.
(AO No. 2020-85, § 1, 10-27-2020)
A. 
Replace first sentence with the following:
A permanent certificate shall be completed by the Energy rater, builder or other approved party and made available to the owner by posting it on a wall in the space where the furnace is located, a utility room, electrical panel or an approved location inside the building.
B. 
Add the following exception:
Exception: A certificate is not required for an addition, alteration, or repair to an existing building.
(AO No. 2020-85, § 1, 10-27-2020)
Add the following to end of paragraph:
Where constructing an assembly with both continuous exterior insulation and stud cavity insulation, a dew-point calculation is required to demonstrate condensation within the assembly is adequately addressed.
(AO No. 2020-85, § 1, 10-27-2020)
Replace the Table N1102.1.2 and footnotes with the following:
Table N1102.1.2
Insulation and Fenestration Requirements by Components
Climate Zone 7
Component
R-Value (Minimum)
Fenestration
3.1
Skylight
1.8
Ceiling
49
Wood Framed Wall
21
Mass Wall
21
Floor over Unheated Areas
38
Basement Wall
15 Continuous or 19 Cavity
Slab on Grade
10 for 36 inches vertically along perimeter
Slab - Heat in slab
10 Under entire slab and for 36 inches vertically along perimeter
Crawlspace wall
15 Continuous or 19 Cavity
(AO No. 2020-85, § 1, 10-27-2020)
Replace the Table N1102.1.4 and footnotes with the following:
Table N1102.1.4
Equivalent U-Factors
Climate Zone 7
Component
Equivalent Maximum U-Factor or F-Factor1
Fenestration
U-0.32
Skylight
U-0.55
Ceiling
U-0.020
Wood Framed Wall
U-0.047
Mass Wall
U-0.047
Floor over Unheated Areas
U-0.026
Basement Wall
U-0.067 Continuous or 0.052 Cavity
Slab on Grade
F-0.51
Slab - Heat in slab
F-0.55
Crawlspace wall
U-0.067 Continuous or 0.052 Cavity
1 Use of opaque assembly U-factors, C-factors, and F-factors from ANSI/ASHRAE/IESNA 90.1 Appendix A is permitted, provided the construction complies with the applicable construction details from ANSI/ASHRAE/IESNA 90.1 Appendix A
(AO No. 2020-85, § 1, 10-27-2020)
Replace section text with the following:
A minimum 11.25 inch truss heel height is allowed to meet the R-49 insulation requirement. Insulation R-values may be lower at eaves to allow for proper ventilation.
(AO No. 2020-85, § 1, 10-27-2020)
Revise the section to read as follows:
Crawlspace walls shall be insulated, and a ground vapor retarder shall be installed in accordance with 23.85. Figure R403-25. Crawlspace wall insulation shall be securely fastened in place and shall extend downward from the floor to the top of the footing. Vapor retarder joints shall overlap 6 inches minimum and be sealed or taped. Vapor retarder edges shall extend not less than 6 inches up and be attached to the footing/stem walls.
(AO No. 2020-85, § 1, 10-27-2020)
Delete sentence and replace with the following:
Stud wall cavities and the spaces between solid floor joists to be used as air plenums shall comply with the following conditions:
1.
Such cavities or spaces shall not be used as a plenum for supply air.
2.
Such cavities or spaces shall not be part of a required fire-resistance-rated assembly.
3.
Stud wall cavities shall not convey air from more than one floor level.
4.
Stud wall cavities and joist space plenums shall be isolated from adjacent concealed spaces by tight fitting fire blocking in accordance with R602.8.
5.
Stud wall cavities in the outside walls of building envelope assemblies shall not be utilized as air plenums.
(AO No. 2020-85, § 1, 10-27-2020)
Amend section N1103.6 to read as follows:
N1103.6 Mechanical ventilation (Mandatory). Ventilation shall be provided in accordance with ANSI/ASHRAE Standard 62.2-2016. Compliance with AHFC Alaska Specific Amendments is optional.
(AO No. 2020-85, § 1, 10-27-2020)
Add the following exceptions:
Exceptions:
1.
AkWarm is an approved heating load calculation methodology.
2.
Equipment shall be sized to meet the load and oversizing shall not exceed 125 percent. When this is not feasible given the discrete size options available, equipment delivering the smallest output while satisfying the calculated load shall be used.
(AO No. 2020-85, § 1, 10-27-2020)
Add an exception as follows:
2.
Compliance with section N1105 may be demonstrated through an AHFC approved home energy rating program that meets the following:
 
a.
A minimum five-star rating is required.
 
b.
The maximum air infiltration rate shall not exceed four air changes per hour at 50 pascals pressure difference.
 
c.
The compliance rating shall be performed by a person authorized by AHFC.
 
d.
Compliance with section 1105.4 is not required.
(AO No. 2020-85, § 1, 10-27-2020)
Amend by deleting in their entirety Chapters 12 through 43, except for the specific sections referenced by the adopted provisions of this code.
(AO No. 2020-85, § 1, 10-27-2020)
Amend the first sentence to read:
These provisions shall apply to manufactured homes, mobile homes, campers, and travel trailers serving as detached single-family dwelling units placed either on private (non-rental) lots or within mobile home parks licensed by the Municipality of Anchorage, and shall apply to the following.
(AO No. 2020-85, § 1, 10-27-2020)
Add the following section:
23.85.AE102.7 Mobile homes, campers, and travel trailers.
23.85.AE102.7.1 Mobile homes. Every mobile home built prior to June 15, 1976, shall be labeled as required in Section AE201, and shall conform to all of the following:
1.
FIRE WARNING SYSTEM - Smoke detectors shall be provided with in accordance with R314.
2.
FIRE PROTECTION - Each mobile home shall be equipped with at least one 2-A rated portable fire extinguisher installed in accordance with NFPA 10-2018.
3.
ELECTRICAL SYSTEM - All electrical equipment, wiring, and appliances shall be installed per Building Safety Handout No. R.10 Mobile Home Set-Up and Permit Requirements, as maintained by the Building Official.
4.
MECHANICAL SYSTEM - All heating equipment shall be maintained in a safe condition. Additions, alterations, repairs and replacements shall comply with manufacturer's instructions and the currently adopted editions of the International Mechanical Code and the International Fuel Gas Code.
5.
PLUMBING SYSTEM - All plumbing facilities shall be maintained in a safe and sanitary condition. Additions, alterations, repairs and replacements shall comply with manufacturer's instructions and the currently adopted edition of the Uniform Plumbing Code.
6.
EXIT FACILITIES - Mobile homes shall have a minimum of two external doors located remotely from each other and so arranged as to provide means of unobstructed travel to the outside of the mobile home.
7.
GROUND FAULT CIRCUIT INTERUPTER (GFCI) - Outlets shall have GFCI protection in accordance with the currently adopted edition of the National Electrical Code (NEC).
(AO No. 2020-85, § 1, 10-27-2020)
Campers and travel trailers shall not be occupied as a permanent dwelling. Campers and travel trailers may be occupied as a temporary dwelling in accordance with the limitations specified in AMC Title 21. When occupied as a temporary dwelling, campers and travel trailers shall be certified by the manufacturer as complying with ANSI A119.5 or NFPA 1192.
(AO No. 2020-85, § 1, 10-27-2020)
Add the following:
CAMPER PARK. A tourist facility approved by the Municipality for use by dependent and independent recreational vehicles, including motor homes, pickup campers, travel trailers, tent campers and similar recreational vehicles as opposed to a mobile home park which is licensed to accommodate mobile homes.
MOBILE HOME PARK. Any parcel or adjacent parcels of land in the same ownership which is utilized for occupancy by more than two mobile homes. This term shall not be construed to mean tourist facilities for parking of travel trailers or campers.
MANUFACTURED HOME:
Add the following at the end of the first paragraph:
Each manufactured home shall bear a certification label in accordance with the Manufactured Home Standards.
MANUFACTURED HOME STANDARDS:
Add the following to the definition:
Every manufactured home installed in the Municipality of Anchorage must be certified for the "North Zone" (40 pounds per square foot) for snow load and heat loss "Comfort Zone 3" in accordance with HUD standards.
(AO No. 2020-85, § 1, 10-27-2020)
Add the following section:
AE301.5 Gas and plumbing service. The owner of a manufactured home or a licensed mobile home contractor may install or retrofit gas piping, gas appliances, or plumbing only under the following conditions:
1.
The owner performing such work shall be a current occupant of the manufactured home and shall personally perform all work.
2.
A licensed mobile home contractor may perform work on gas and plumbing utility connections only by use of a licensed journeyman plumber or journeyman gas fitter who is an employee of the contractor. All such work shall bear a tag with the identification number of the journeyman plumber or journeyman gas fitter who performs the work.
3.
Except as provided in items 1 and 2 of this section, all plumbing, gas piping, or gas appliance retrofit work shall be performed by a licensed plumbing or gas contractor.
4.
No person may pipe natural gas to service gas fired equipment unless:
 
a.
Such equipment has been certified by the manufacturer as being suitable to that use; and
 
b.
Such equipment has first been converted for use of natural gas.
(AO No. 2020-85, § 1, 10-27-2020)
Add the following section:
AE302.4 Who may apply. Only the owner of a manufactured home or a licensed mobile home contractor may apply for a permit under this Section.
(AO No. 2020-85, § 1, 10-27-2020)
Add the following sentence to AE307.1:
All sewer, electricity, gas, and water services shall be installed and maintained in a safe manner in accordance with the appropriate adopted codes.
(AO No. 2020-85, § 1, 10-27-2020)
Replace the last sentence of the first paragraph with the following:
Footings shall have a minimum depth of 42 inches below exterior grade on privately owned (non-rental) lots, unless a greater depth is required by the Building Official based on a foundation investigation or other information. Footings or piers in mobile home parks may be placed at surface grade, provided all other requirements are met.
(AO No. 2020-85, § 1, 10-27-2020)
Add the following to the second paragraph:
Where combustion air is not taken from the crawl space, and where the floor area of the home does not exceed 800 square feet, the ventilation requirement may be met by operable vents of 8 inches by 16 inches installed in skirting not less than 18 inches above exterior grade at opposite ends of the manufactured home.
(AO No. 2020-85, § 1, 10-27-2020)
Replace the first sentence of the first paragraph with the following:
Every manufactured home shall be skirted around its perimeter from the floor line to exterior grade with a skirting material having an insulation value of R-19 as published by the American Society of Heating, Refrigeration, and Air Conditioning Engineers (ASHRAE). A minimum of 6 mil polyethylene film vapor retarder shall entirely cover the soil surface of the crawl space.
(AO No. 2020-85, § 1, 10-27-2020)
Replace the first paragraph with the following:
Ground anchors shall be designed and installed to resist overturning and lateral movement of the manufactured home, and shall extend at least 60 inches below exterior grade, or deeper if required by the Building Official because of poor soils. Ground anchors shall be installed for every manufactured home, except where a permanent foundation bearing at least 42 inches below grade is demonstrated by calculation to resist the forces as determined by Chapter 16 of the International Building Code.
(AO No. 2020-85, § 1, 10-27-2020)
Add after first paragraph:
Exceptions:
1.
Accessory dwelling units as defined by AMC Title 21.
2.
Existing wall and floor-ceiling assemblies.
(AO No. 2021-88(S), § 17, 2-15-2022)