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Building Codes

Every three years, new model construction codes are published through the International Code Council (ICC). The State Building Code Council (SBCC), with the assistance of their Technical Advisory Groups (TAGs), adopt those applicable to our state.

2015 Residential Construction Code Now In Effect

The SBCC has adopted the 2015 editions of the International Building Code (IBC), International Residential Code (IRC), International Fire Code (IFC), International Mechanical Code (IMC) and Uniform Plumbing Code (UPC) with state amendments; and the 2015 Washington State Energy Code (WSEC). The 2015 code became effective July 1, 2016.

BIAW's 2015 Code Changes PowerPoint Presentation

If you missed the chance to attend BIAW's Significant Changes to the 2015 Codes class, you can download and view the Code Changes PowerPoint Presentation here.

Washington State Energy Code Updates

The 2015 Washington State Energy Code, which is actually a combination of the 2015 International Energy Conservation Code (IECC) and the 2012 Washington State Energy Code (WSEC), has now been divided into commercial and residential provisions - both are available to download below:

Based on the 2015 IECC; "Residential" includes one- and two-family dwellings, townhouses and group R-2 and R-3 buildings three stories or less. "Commercial" includes all buildings not covered under "residential."

Below are highlights of the revisions and significant changes to the WSEC:

  • Additional Energy Efficiency Requirements, Chapter R406
    This section was expanded to include all low-rise residential dwelling and sleeping units, not just IRC buildings. The updated requirements increases the number of credits required for each dwelling and size to the following:
    • .5 credits for an addition less than 500 s/f
    • 1.5 credits for additions over 500 s/f and a house under 1500 s/f
    • 2.5 credits for dwelling units serving R-2 occupancies
    • 3.5 credits for house 1500 to 5000 s/f
    • 4.5 credits for a house over 5000 s/f
    • The list of options for compliance has to be reorganized and expanded. There is also an adjustment of the credit allowances for some of the options
  • Energy Compliance
    Performance-based compliance includes changes to simulated energy performance required per square foot of condition floor area.
  • Mini-split Heat Pumps
    All detached one- and two-family dwellings and multiple single-family dwellings (townhouses) up to three stories using electrical zonal heating as the primary heat source, must now install an inverter-driven ductless mini-split heat pump in the largest zone in the unit.

International Residential Code Updates

Download the 2015 International Residential Code State amendments insert pages which includes the adoption of Appendices F and Q. Chapter 11 and Chapters 25-43 are not adopted.

Below are highlights of the revisions and significant changes to the IRC.

  • Decks
    Decks have been the subject of revisions over the past two code cycles and now have been elevated to a stand-alone section, which includes prescriptive guidance on the following:
    • Fastening requirements with placement of lag screws and bolts
    • New span tables
    • New wood species
    • Deck ledger connections
  • Solar Energy Systems
    Installation of solar energy systems including specs for roof load, wind resistance and building-integrated PV systems.
  • Coastal Area Design Criteria
    This applies to a salt-water coastal area listing to be designated locally.
  • Swimming Pool/Spas
    By reference, inclusion of the 2015 International Swimming Pool and Spa Code for all residential design and construction applications.
  • Green Building Efficiency
    New appendices for light straw clay and staw bale construction.

Additional Code Resources

You can purchase I-Codes books from the International Code Council. If you are a ICC member, contact Al Audette to receive the member discount.

More code update information:

Carbon Monoxide Alarms

The requirement for mandatory carbon monoxide alarms for all new construction have been in place since January 1, 2011, as adopted by the SBCC as part of the 2009 code cycle.

  • As of April 1, 2012 when a permit is issued for an alteration, repair, addition or creation of additional sleeping rooms, the installation of a carbon monoxide alarm is required.
  • Code requires the seller of any owner-occupied single-family residence sold on or after June 26, 2009 to equip the residence with carbon monoxide alarms. In June 2012, a law went into effect that requires amendments to seller's disclosure forms in purchase and sale agreements to ensure that the responsibility for placement of carbon monoxide alarms is that of the seller.
  • As of January 1, 2013 ALL buildings that are classified as residential occupancies (including rentals homes, duplexes, apartments, etc.) must be equipped with carbon monoxide alarms, with the exception of owner-occupied, single-family residences occupied before July 26, 2009.

View the detailed report of Washington's carbon monoxide alarm laws here.


If you have any questions regarding residential building codes and regulations, please contact Codes and Regulations Manager Al Audette.

  Al Audette
Codes and Regulations Manager
360-352-7800, ext. 105