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Thurston County, Washington Building Codes

Updated : 04/22/2024

Overview

Thurston County, Washington, adopted the 2018 International Residential Code (IRC), including Appendices F, Q, and V, with amendments. Thurston, WA, Muni. Code § 14.18.010 (adoption) and §§ 14.18.020-14.18.060 (amendments). Thurston County, Washington, adopted the 2018 International Building Code (IBC), including Appendices C, E, and J, with amendments. Thurston, WA, Muni. Code § 14.17.010 (adoption), Chapter § 14.37 (appendix J), Chapter § 14.46 (appendix C)and §§ 14.17.020-14.17.090 (amendments). Thurston County, Washington, adopted the 2018 International Existing Building Code, including Appendix A, with amendments. Thurston, WA, Muni. Code § 14.19.010 (Adoption) and §§ 14.19.020-14.19.090 (amendments). 

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

Helpful resources for Thurston County, Washington include the following.

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.

Thurston 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)(Thurston County, WA 14.35.010 - Adoption.)

...A. That portion of the State Building Code known as the International Energy Conservation Code—Residential as defined in RCW 19.27.031, as amended and updated by the State Building Code Council pursuant to RCW 19.27.074, Chapter 51-11R WAC, and as amended in this chapter, except to the extent prohibited...

Drip Edge

Drip Edge: yes

Ice Barrier

Are ice barriers required for Thurston County ? No
Comments:

No amendments to the IRC Table 301.2 were found in the municipal code. However, climate design criteria were found on the Thurston County website.

Ground Snow Load: 20 pounds per square foot

Wind Speed: IRC = ultimate wind speed 110 mph Figures R301.2(5)A

IBC Table: 1609.3.1& ASCE-07-16 = V basic 100 mph

Topographic Effects: No

Seismic Design Category: D2 unless information demonstrates that the site Sds is less than or equal to .83g on the United States Geological Survey Seismic Design Maps.

Weathering: Slight to moderate

Frost Depth: 12 inches

Termites: Slight to moderate

Decay: Slight to moderate

Winter Design Temperature: 17° Fahrenheit

Ice Shield Required: No

Flood Hazard Flood information is specific to the property location. Links below:
     • Check the county’s online property map to see if a property is in a flood area. Scroll to the Property Critical & Environmental Areas Look Up section.
     • Find information about development in flood areas. • Email a question about development in a flood area.

Air Freezing Temperature: See the Washington State Energy Code online at Washington State University Energy Program https://www.energy.wsu.edu/buildingefficiency/energycode.aspx.

Mean Annual Temperature: See the Washington State Energy Code, same link as above.

Thurston County. "Building Code Climatic and Geographic Info Fact Sheet." Thurston County. January 1, 2023. https://s3.us-west-2.amazonaws.com/thurstoncountywa.gov.if-us-west-2/s3fs-public/2023-01/cped-permit-docs-building-code-climatic-and-geographic-info-fact-sheet.pdf.

Comments

Thurston County, Washington, adopted the 2018 International Residential Code (IRC), including Appendices F, Q, and V, with amendments. Thurston, WA, Muni. Code § 14.18.010 (adoption) and §§ 14.18.020-14.18.060 (amendments). Note that the 2018 IRC is the current effective code until March 15, 2024, when the 2021 edition will become effective. See PLRBWashington 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.

No adoption of Appendix J was found in the municipal code or city website. 

Thurston County, Washington, adopted the 2018 International Existing Building Code, including Appendix A, with amendments. Thurston, WA, Muni. Code § 14.19.010 (Adoption) and §§ 14.19.020-14.19.090 (amendments). Note that the 2018 IEBC is the current effective code until March 15, 2024, when the 2021 edition will become effective. See PLRBWashington Building Codes

Commercial Building Code

Thurston 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)(Thurston County, WA Municipal Code)

...Adoption not found...

Comments

Washington, adopted the 2018 International Building Code (IBC), including Appendices C, E, and J, with amendments. Thurston, WA, Muni. Code § 14.17.010 (adoption), Chapter § 14.37 (appendix J), Chapter § 14.46 (appendix C)and §§ 14.17.020-14.17.090 (amendments). Note that the 2018 IBC is the current effective code until March 15, 2024, when the 2021 edition will become effective. See PLRBWashington Building Codes

Existing Buildings

Thurston County, Washington, adopted the 2018 International Existing Building Code, including Appendix A, with amendments. Thurston, WA, Muni. Code § 14.19.010 (Adoption) and §§ 14.19.020-14.19.090 (amendments). Note that the 2018 IEBC is the current effective code until March 15, 2024, when the 2021 edition will become effective. See PLRBWashington Building Codes

Other Building Codes

Thurston County, Washington, adopted the 2018 International Mechanical Code with amendments. Thurston, WA, Muni. Code § 14.24.010 (adoption) and §§ 14.24.020-14.24.040 (amendments).

Thurston County, Washington, adopted the 2018 International Fuel Gas Code with amendments. Thurston, WA, Muni. Code § 14.26.010 (adoption) and §§ 14.26.020-14.26.040 (amendments).

Thurston County, Washington, adopted the 2018 Uniform Plumbing Code, including Appendices A, B, and I, with amendments. Thurston, WA, Muni. Code § 14.28.010 (adoption) and §§ 14.28.020-14.28.030 (amendments).

Thurston County, Washington, adopted the 2018 International Fire Code, including Appendices B, C, E, F, and G, with amendments. Thurston, WA, Muni. Code § 14.32.010 (adoption) and §§ 14.32.020-14.32.230 (amendments).

Thurston County, Washington, adopted the 2018 International Wildland Urban Interface Code (WUIC) is included in this code as Section 8200 with amendments found in Appendix Chapter N. Wash. Admin. Code § 51-54A-007. Note that no adoption was found in the municipal code but the building construction page shows the adoption of the 2018 International Wildland Urban Interface Code.  

Thurston County, Washington, adopted the 2018 International Energy Conservation Code with amendments. Thurston, WA, Muni. Code § 14.34.010 (commercial adoption), §§ 14.34.020-14.34.050 (commercial amendments), § 14.35.010 (residential adoption), and §§ 14.35.020-14.35.050 (residential amendments).

Thurston County, Washington, adopted the National Electrical Code (NFPA 70). See Labor & Industries (L&I), “Electrical Laws, Rules & Policies.” Licensing & Permits, Lni.wa.gov (state adoption and amendments),

Thurston County, Washington, adopted the National Fuel Gas Code (NFPA 54 for LP Gas). Revised Code of Wash. § 19.27.031(2) and Thurston, WA, Muni. Code § 14.24.010 (IMC adoption). 

Thurston County, Washington, adopted the Liquefied Petroleum Gas Code (NFPA 58). Revised Code of Wash. § 19.27.031(2) and Thurston, WA, Muni. Code § 14.24.010 (IMC adoption). 

Thurston County, Washington, adopted the 2009 ICC/ANSI A117.1 Accessible and Usable Buildings, and Facilities, with statewide amendments. Wash. Admin. Code § 51-50-005 and Thurston, WA, Muni. Code § 14.17.010 (IBC adoption).

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