Building code changes eventually impact all of us, to some degree. These energy construction codes in Washington change every three years, part of a mandate to reduce our energy consumption 70 percent between the 2006 codes and the year 2030. Washington adopts the international codes for residential, commercial, and plumbing; our energy code uses the International Energy Conservation Code as its basis. 

Though local jurisdictions are required to adopt these codes statewide, many items in each code are open for interpretation by the local code official. In some cases, local amendments to the code will prevail. As an example, trade professional can be working on a job subject to certain codes or regulations one week, then drive 15 minutes to look at a prospective job in another city that could be enforcing the same code entirely different. You can usually count on the local building inspector to share where your methods are out of compliance, but that is not only inefficient but possibly very expensive, depending on the fix.

The text below explains the 2015 code updates that went into effect July 1, 2016. This information was collected and presented to the Remodelers Council of the Master Builders Association (MBA) of King and Snohomish Counties on June 16, 2016 by Jan Rohila and Al Audette from the Building Industry Association of Washington.

1. WSEC Changes

The 2015 Washington State Energy Code (WSEC) combines the 2015 International Energy Conservation Code (IECC) from the International Code Council (ICC) with the WSEC from 2012. The following highlight some of the more significant changes to the codes, beginning with the WSEC.

  • This year’s code changes have been divided in two: one for residential and one for commercial. Both are available to download on the BIAW website at From there, click on the top article under ‘Latest News.’

  • Residential now covers all R2; apartments and low-rise are now included.  

  • The inspection process now covers five different installation inspections which may change from jurisdiction to jurisdiction; talk to your local code official and find out how they want to handle these inspections.

  • Certificates previously had to be placed within three feet of the electrical box, but the updates now allow them to be placed in a utility room or other location that's approved by your local jurisdiction.

  • The 2015 WSEC allows specific leakage area testing of five air changes per hour, which is no change but now includes an exception for additions that are less than 500 square feet. Remodels to homes built before 2009 can test to seven air changes per hour.

  • Duct installation was R8, and is now R10. As for duct testing, the only change is that the certificate now has to be signed. There is still no requirement specifying who is required to do the duct testing, but it has to be a signed certificate, and that certificate has to be provided to the local code official.                   

  • In previous WSEC codes, hot water pipe installation was R4. R4s remain a special order. Thankfully, R3 is now memorialized in the code itself instead of by emergency rule.                       

  • If you do electric resistance or baseboard heating on all R2 units, the code updates require you now have to install a ductless heat pump in the largest zone in the house. While this increases cost, the tradeoff is that you still get the one credit for it (when it comes time to meet your energy compliance).

  • Existing buildings have been moved into one chapter in the newest update. They have now put everything that applies to alterations in existing buildings into one chapter. There is a caveat here. Historic buildings no longer get an automatic pass, which used to be uniform. You can still work with your local code official because the way it's worded, historic buildings must comply to the extent that such compliance does not compromise the historic nature and function of the building.  

  • Energy efficiency requirements have shifted, and the number of credits have increased. Let’s think through some examples. A small dwelling (less than 1,500 square feet) has gone from a half a credit to one and a half credits. The original, until the final adoption, was two and a half credits. Medium dwellings increased by two credits, and a large dwelling increased by two credits. So if you're building a house or an addition that's more than five thousand square feet, you now have to have four and a half credits. Additions of more than five hundred square feet must have a half credit. Some of these credit increases can be easy to meet, just by installing low-flow shower heads and faucets which achieve a half credit.

  • Solar-ready provisions have been added to the WSEC code updates. That means the solar-ready provisions in the appendix must be followed. The same is true for the fire sprinkler code. If you're going to mandate fire sprinklers, you have to follow the appendix that's in the code.

For the 2015 WSEC updated codes, tools for compliance, performance path, and prescriptive path compliance have not changed. 

2. International Residential Code (IRC) Changes

Let's talk about the 2015 International Residential Code (IRC), with updates that are a little more amenable.

  • Accessory structures were two stories and are now three, with square footage limitations removed. Alternative material design and methods of construction—for those who do high-end green buildings—you can now go to your local code official and say, "I have an alternative method of construction, this is what I'd like to do." Typically, they will approve it. If not, they must give you a written explanation of why they will not approve that alternative method.

  • There are now five categories of sun rooms, factoring the intended use of the space, type of egress, natural ventilation, and resistance of the exterior envelope to air leakage. This means there's a lot more options available for habitable and non-habitable sun rooms.

  • Townhouse separation is now memorialized in code, and includes an assigned fire resistance rating. This was an emergency rule last time.

  • The IRC codes have added locations and distance to allow for cooking appliances in close proximity to smoke alarms, so they're not accidentally set-off. As for carbon monoxide alarms, the IRC now requires a CO2 alarm in a bedroom where there is a fuel-fired appliance, either in the bedroom or in an adjoining bathroom. Further, the IRC now requires a CO2 alarm on each level of the dwelling. House-wiring with a backup is still required, and then battery operated detectors are permitted for alterations, repairs, and additions to existing buildings.

  • Swimming pools and spas now have their own code, which has moved out of the appendix into Chapter 42.

  • As for minimum footing size, there are new variations best understood by the brand new chart, which you’ll want to consult. This has been a frustrating change. The Spokane regional codes group has come up with an Excel spreadsheet that has been accepted for use in most jurisdictions. If you build in the Tri-Cities area, you will need to talk to your building official before starting, to ensure they will approve your footing sizes.

  • The IRC codes have doubled the maximum height on retaining walls before you have to go to engineering. If you’re using it for parking—or if a fence or structure extend off the wall—then you're back to the 24” before engineering is required. But just for a retaining wall that holds back dirt, the maximum is up to 48".

  • Decks finally have their own chapter—chapter five. There was a conflict between a Washington amendment in chapter three and the ICC in chapter five, but the state building code council says we're going to discount the chapter three in favor of chapter five. It was the difference between 60 live load versus 40 live load for clear span.  

  • The fastening schedule has been vastly updated, and includes instructions about commonly used nail guns, and more hold downs. The big change here is that we went from the required takeaway. They did some testing, and found out that the holding capacity could be reduced from 4,200 to 3,500 pounds, while two plates are sufficient instead of the current three.  

  • Insulated vinyl siding and polypropylene siding: The code now requires further setbacks because of heat deformation, which occurs when the sun reflects off windows of one house onto siding of a neighboring house.

  • There is a new chapter for foam sheeting and shingles, which rolls into some of the other things that go with the changes to the electrical code.

  • The IRC is allowing alternating tread devices and ship ladders. Washington amendment allows for use as a means of egress within an individual dwelling unit, such as access to areas of 200 square feet or less, and not containing the primary bathroom or kitchen. In the last code cycle, they measured the guard rail height from the fixed seating that's attached, and now it doesn't matter if there's fixed seating attached. Measure from the deck surface. One thing to remember about this—the IRC and the IBC do not agree here. The IRC allows you to measure the guard rail height from the flooring. The IBC still says you have to measure it from fixed seating. There's a change there, and they're not consistent though they usually are. We'll probably see it change in the next code cycle.

  • Exhaust duct power ventilators with boosters are now accepted. To use a booster, there's a chart that goes with it that shows the booster size and the length of the duct that you can expand to. If you do light straw-clay or straw-bale construction, you will need to consult Appendices R and S.

  • Similar to the solar-ready changes in the WSEC updates, Appendix U is a new appendix defining solar-ready changes in the IRC codes as well. Of course, make sure your jurisdiction is allowing for solar-ready first. There is an emergency rule if you do 502 facilities.

This is just a summary of several key changes in the IRC and WSEC codes. Be sure to consult the appropriate literature as you implement these changes.

Jan Rohila is the Building Industry Association of Washington (BIAW) Administrative Services Director.

As BIAW's Codes and Regulations Manager, Al Audette follows issues at the International Code Council as they work their way through the code adoption process.