Chapter 21.10
INTERNATIONAL RESIDENTIAL CODE

Sections:

21.10.010    International Residential Code adopted.

21.10.013    Copies on file.

21.10.016    Administration.

21.10.020    IRC Table R301.2 amended.

21.10.025    Repealed.

21.10.010 International Residential Code adopted.

The 2021 Edition of the International Residential Code, as adopted by the State Building Code Council in Chapter 51-51 WAC, as published by the International Code Council, excluding Chapter 1, “Administration,” is adopted, together with the following amendments. The Construction Administrative Code, as set forth in Chapter 21.06, shall be used in place of IRC Chapter 1, Administration. (Ord. 4848 § 30, 2024; Ord. 4751 § 27, 2021; Ord. 4524 § 46, 2016: Ord. 4410 § 7, 2013: Ord. 4246 § 3 (part), 2010: Ord. 4099 § 4 (part), 2007: Ord. 3946 § 1 (part), 2004)

21.10.013 Copies on file.

The city shall at all times keep on file with the city clerk, for reference by the general public, not less than one copy of the International Residential Code. (Ord. 4246 § 3 (part), 2010: Ord. 4208 § 4 (part), 2009)

21.10.016 Administration.

The administrative provisions for the enforcement of the International Residential Code are located in Chapter 21.06. (Ord. 4246 § 3 (part), 2010: Ord. 4208 § 4 (part), 2009)

21.10.020 IRC Table R301.2 amended.

IRC Table R301.2 is amended to read:

TABLE R301.2

CLIMATIC AND GEOGRAPHIC DESIGN CRITERIA

ROOF SNOW LOADa (psf)

WIND DESIGN

SEISMIC DESIGN CATEGORY

SUBJECT TO DAMAGE FROM

OUTDOOR DESIGN TEMP (F) - Heat/

Cool

ICE BARRIER UNDERLAYMENT REQUIRED

FLOOD HAZARDe

AIR FREEZING INDEX

MEAN ANNUAL TEMP

Speedb (mph)

Topographic effectsc

Special wind region

Windborne debris zone

Weatheringd

Frost line depth

Termite

25

98

Yes

No

No

D2

Moderate

12”

Slight to Moderate

83/17

No

N.A.

113

53oF

MANUAL J DESIGN CRITERIA

Elevation

Altitude correction factor

Coincident wet bulb

Indoor winter design dry-bulb temperature

Indoor winter design dry-bulb temperature

Outdoor winter design dry-bulb temperature

Heating temperature difference

338 feet

0.99

66oF

72oF

72oF

24oF

48oF

Latitude

Daily Range

Indoor summer design relative humidity

Summer design gains 50% RH

Indoor summer design dry-bulb temperature

Outdoor summer design dry-bulb temperature

Cooling temperature difference

47o39’26’’

M

50%

5

75oF

83oF

8oF

a.    This is the minimum roof snow load. When using this snow load it will be left to the engineer’s judgment whether to consider drift or sliding snow. However, rain on snow surcharge of 5 psf must be considered for roof slopes less than 5 degrees.

b.    The basic wind speed is determined from the basic wind speed map in Figure R301.2(2). Wind exposure category shall be determined on a site-specific basis in accordance with Section R301.2.1.4.

c.    Topographic effects (Wind Speed-up Kzt factor) shall be determined on a site-specific basis in accordance with Section R301.2.1.5.

d.    Weathering may require a higher strength concrete or grade of masonry than necessary to satisfy the structural requirements of this code. The grade of masonry units shall be determined from ASTM C34, C55, C62, C73, C90, C129, C145, C216 or C652.

(Ord. 4848 § 31, 2024; Ord. 4751 § 28, 2021; Ord. 4524 § 47, 2016: Ord. 4410 § 8, 2013: Ord. 4246 § 3 (part), 2010: Ord. 4099 § 4 (part), 2007)

21.10.025 IRC 311.7.7, Stairway walking surface, amended.

Repealed by Ord. 4848. (Ord. 4751 § 29, 2021)