Addendum to "Treated Wood Deck Framing Rules Get Tougher."

The latest 2016 ICC AC236 is based on language from the AWPA Standard U1, Mike O’Reardon told JLC. The criteria requires companies to provide new installation instructions specifying “Ground Contact” material in certain above-ground locations. Here is the relevant language:

6.8 Sample Table—Typical Applications; A table with typical applications for product uses must be included in the evaluation report, refer to Figure 3 and the evaluation report must include as part of the Installation instructions a description of the physically above ground applications and require them to be treated to ground contact (AWPA Use Category 4A) requirements.

6.8.1 Components which are difficult to maintain, repair or replace and are critical to the performance and safety of the entire system/construction. Examples would be typical deck or dock joists or beams.

6.8.2 Components subject to hazards comparable to ground contact due to climate, artificial or natural processes or construction which include the following:

  • When there is a reasonable expectation that soil, vegetation, leaf litter or other debris may build up and remain in contact with treated wood.
  • When the construction itself, other structures or anticipated vegetation growth will not allow air to circulate underneath the construction and between decking boards.
  • When treated wood is installed less than six inches above the ground (final grade after landscaping) and supported on permeable building materials such as treated wood or concrete.
  • When treated wood is in direct contact with non-durable untreated wood or any older construction with any evidence of decay.
  • When treated wood is wetted on a frequent or recurrrent basis such as on a freshwater floating dock or by a watering system.
  • When treated wood is used in tropical climates.