Building Codes FAQs

The 2021 Building Codes will go into effect March 15, 2024.

Will the codes be delayed again?

The State Building Code Council has indicated it will not entertain another delay to code implementation.

That being said, a coalition of energy choice advocates have re-filed a lawsuit in Thurston County Superior Court that may impact code implementation > learn more

Where do I find the changes to the code?

Click the links to be redirected to the official filings for each code:

  • Residential Code with Washington Amendments > view
  • Wildland Urban Interface Code > view
  • Residential Energy Code > view
  • Electrical Code > view
    • To go into effect April 1, 2024 per L&I
  • Looking for another code? click here

What resources are available to help me comply with the energy code?

WSU Energy has compiled a list of resources to help with compliance > click to be redirected

Can I use natural gas under the new energy code?

It depends. Our state code HEAVILY disincentivizes natural gas use because it’s a fossil fuel.

If using natural gas, BIAW has found compliance is 3 TIMES more expensive than all-electric buildings, largely due to the amount of solar needed to offset disincentivization; even if your project doesn’t have ample opportunity for sunlight.

Can my HVAC contractor still sell me a natural gas furnace?

The new codes only apply to new HVAC systems that are included in new builds and/or replacements of HVAC equipment in existing homes that are being upsizing.

You may use natural gas if you’re renovating and/or doing an HVAC like-for-like system swap. This means you’re not able to increase the size of your existing natural gas furnace even if it doesn’t deliver enough heat for the square footage of your existing home.

Example: if you’re not satisfied with the level of heating produced by your current system so you want to upgrade to a more powerful unit, you would potentially have to utilize an electric alternative.

We are aware this is an interstate commerce issue. To raise the prominence of the issue, please contact your congressperson.

Options for Energy Code Compliance

BIAW has compiled the credit options, and required pairings of credits, for use by our members.

To view, click the “See the Board” button below.

Does BIAW offer any recommended pathways for compliance?

All information, content, and materials regarding pathways for energy code compliance are for general informational purposes only, and do not constitute a formal recommendation from the Building Industry Association of WA (BIAW). No reader or user of this information should act or refrain from acting on the basis of this information without consulting the appropriate professionals. All liability with respect to actions taken or not taken based on the information provided are hereby expressly disclaimed.


Medium Dwelling Unit = 8 credits needed

R406.2 Energy Equalization Credits
Ductless Mini-Split: Type 4 = 3 credits


R406.3 Energy Credits

  1. Option 1.2 = 1 credit
  2. Option 3.7 = 2 credits
  3. Option 5.6 = 2 credits

What's the deal with continuous insulation?

You currently have two options (please choose one or the other):

  1. Following the Prescriptive Path, you would need to do an R-21 cavity PLUS R-5 continuous insulation on the exterior.
  2. If however, you use the Total U-Value Alternative within the Performance Pathway, you may use a total building calculation that utilizes the SBCC’s most recent change to the above grade wall U-value. One of the easiest ways to demonstrate compliance with this option is to use the WSU C3 calculator.

Download the C3* Calculator and Permit Forms at this link

Please note: C3 requires Excel for Windows installed on your computer (not web-based) and is not available for Mac computers.

Disclaimer: Results from the C3 assume that all data is entered correctly and completely. Results do not constitute an official decision. Your analysis should be reviewed by your building official/authority having jurisdiction.

*C3 means code compliance calculator.

What's the status on the WUI code?

Currently, implementation is pending for March 15, 2024. However, if SB 6120 passes the Washington Legislature, no statewide WUI codes will be implemented. If passed, SB 6120 will have DNR re-do the WUI map based on wildfire risk and would bar the SBCC from enforcing the state code.

*Please note: some local jurisdictions have already implemented the code. If you believe you’re building in a high-risk area, please consult with your local planning department.

To view a webinar that was provided to BIAW members from WABO, please click here.

Who should I ask regarding technical questions?

Your local building department should be your first-stop in navigating the new codes.

If your planning department hasn’t fully answered your question and/or they too have questions still, please direct those questions to