Updated : 04/22/2024

Overview

Mason County, Washington, adopted the 2018 International Building Code, including Appendices C, G, H (except chapter H106), and J, with amendments. Mason County, WA, Muni. Code § 14.04.010 (adoption) and §§14.08.010-14.08.135 (amendments). Mason County, Washington, adopted the 2018 International Residential Code, including Appendix R and S. Mason County, WA, Muni. Code § 14.04.010 (adoption) and §§14.08.010-14.08.135 (amendments). Note that the municipal code shows Appendix "CR"; there is no Appendix CR in the 2018 IRC; however, light straw clay construction is in Appendix R. Mason County, Washington, adopted the 2018 International Existing Building Code (IEBC). Mason County, WA, Muni. Code § 14.04.010 (adoption). Note that Washington adopted the 2015 IEBC by amending the reference to the IEBC in §101.4.7 of the 2018 IBC. See PLRB, Washington Building Codes, and Wash. Admin. Code § 51-50-007 (state codes).

Note that the above codes are the current effective codes until March 15, 2024, when the 2021 edition will become effective. See PLRB, Washington Building Codes.

Helpful resources for Mason County, Washington include the following.

• Jurisdiction's Information Page(s):
  • Mason County, Washington Municipal Code
• PLRB, Ordinance and Law Coverage Discussion for Washington

Residential Building Code

Washington adopted a statewide mandatory residential code that will control; however, local governments are free to make laws more strict (with some limitations).See PLRB, Washington Building Codes for more information on state level codes.

Mason County adopted the 2018 IRC, locally. Note that adoptions usually come with amendments. So, it is important to review those amendments in addition to the unamended model code.

You can find a copy of the model code here.

You can find information about amendments to the model code here.

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2021 Washington State Residential Code (2021 IRC)(Mason County, WA STATUTORY REFERENCES)

...RCW chs. 36.57, 36.57A Airports  RCW chs. 14.07, 14.08 Buildings and Construction State building code  RCW ch. 19.27 Energy-related building standards  RCW ch. 19.27A Adoption of building codes...

Drip Edge

Drip Edge: yes

Ice Barrier

Are ice barriers required for Mason County ? No
Comments:

No amendment to the IRC Table 301.2 was located in the municipal code. However, a climate design criteria was found on the Mason County website. Mason County, WA. “Climatic and Geographic Design Criteria.” Accessed October 18, 2023. https://masoncountywa.gov/community-services/building/design-criteria.php.

Ground Snow Load: 25-55 psf
Basic Wind Speed:
    85 (Basic), 110 Ultimate with 3-second wind gust
    Figure R301.2(4)A
    Exposure site specific
    See R301.2.1.4
Topographic Effects: No
Seismic Design Catagory: D2
Winter Design Temp: 23ºF
Ice Shield Underlayment Required: No
Flood Hazard: 
    (a) Feb. 1991
    (b)May 1988
    (c) 5301150 #25 through 300
    revised 1998
Air Freezing Index: 170
Mean Annual Temp: 51ºF
PSF: 1500 soils
Weathering: Moderate
Frostline Depth: 12"
Termites: Slight to moderate
Decay: Slight to moderate

Mason County, WA. “Climatic and Geographic Design Criteria.” Accessed October 18, 2023. https://masoncountywa.gov/community-services/building/design-criteria.php. 

Comments

Mason County, Washington, adopted the 2018 International Residential Code, including Appendix R and S, with amendments. Mason County, WA, Muni. Code § 14.04.010 (adoption) and §§14.08.010-14.08.135 (amendments). Note that the municipal code shows Appendix "CR"; there is no Appendix CR in the 2018 IRC; however, light straw clay construction is in Appendix R. 

Note that the above codes are the current effective codes until March 15, 2024, when the 2021 edition will become effective. See PLRB, Washington Building Codes. 

Existing Buildings

Existing buildings, meaning buildings that were built in accordance to code at the time of construction, typically merit extra consideration in a current updated code.

Mason County, Washington, adopted the 2018 International Existing Building Code (IEBC). Mason County, WA, Muni. Code § 14.04.010 (adoption). Note that Washington adopted the 2015 IEBC by amending the reference to the IEBC in §101.4.7 of the 2018 IBC. See PLRB, Washington Building Codes, and Wash. Admin. Code § 51-50-007 (state codes).

Note that the above codes are the current effective codes until March 15, 2024, when the 2021 edition will become effective. See PLRB, Washington Building Codes. 

Commercial Building Code

Mason County adopted the 2018 IBC, locally. Note that adoptions usually come with amendments. So, it is important to review those amendments in addition to the unamended model code.

You can find a copy of the code here.You can find information about amendments to the model code here.

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2021 Washington State Building Code (2021 IBC)(Mason County, WA Municipal Code)

...Adoption not found...

Comments

Mason County, Washington, adopted the 2018 International Building Code, including Appendices C, G, H (except chapter H106), and J, with amendments. Mason County, WA, Muni. Code § 14.04.010 (adoption) and §§14.08.010-14.08.135 (amendments). 

Note that the above codes are the current effective codes until March 15, 2024, when the 2021 edition will become effective. See PLRB, Washington Building Codes. 

Existing Buildings

Mason County, Washington, adopted the 2018 International Existing Building Code (IEBC). Mason County, WA, Muni. Code § 14.04.010 (adoption). Note that Washington adopted the 2015 IEBC by amending the reference to the IEBC in §101.4.7 of the 2018 IBC. See PLRB, Washington Building Codes, and Wash. Admin. Code § 51-50-007 (state codes).

Note that the above codes are the current effective codes until March 15, 2024, when the 2021 edition will become effective. See PLRB, Washington Building Codes. 

Other Building Codes