Building > Adopted Construction Codes
Presecriptive Deck Codes changed in the 2015 Edition of the International Residential Code. Click on this Link, and scroll down to Section R507. Previous illustrated versions are on the web, but currently (a/o April 2015) do not reflect the mandated July 2016 Washington State adopted language. Why? Wood exposed to rain and snow is heavier than an interior (dry) floor system, so the wood framing members are spaced closer, and don’t span as far.