The new standard change will require that Ground Contact (UC4A) treated wood be used in the following end use applications:
|Ground Contact Use Guide
For Decks & Docks
Ground Level Decks and Walkways
- Treated wood when installed less than 6” above the ground.
- When treated wood is used in an application that does not permit air circulation or water drainage underneath the structure.
- When treated wood is used in an application where vegetation, leaf litter, or other debris will build up and remain in contact with the treated wood product.
Decks and Fresh Water Docks
- When treated wood is used in an above ground application where the treated wood component would be considered difficult to maintain, repair or replace and that component is critical to the performance and safety of the structure. This standard change will affect joists and beams used in above ground decks and fresh water docks, including floating docks.
- When treated wood is wetted on a frequent or recurring basis such as wind and wave action (such as fresh water docks and walkways) or watering systems, swimming pools and hot tubs.
Export Products - Exterior Use
- When treated wood is used in tropical climates.
AWPA U1 Standard and 2015 International Residential Code (IRC)
- The American Wood Protection Association (AWPA) has changed the U1 standards for treated wood used in residential, agricultural and commercial applications. The AWPA Book of Standards states, “Standard U1 is the primary standard for specifiers, such as architects and engineers, but also for end users and building code officials. This Standard contains the information needed by specifiers in order to select a product that best suits their needs.”
- The residential code (IRC) states that wood that is preservative-treated must be in accordance with the AWPA U1 Standard.
- One of the new revisions to the AWPA U1 Standard will change deck and fresh water dock joists and beams to Ground Contact, because those components are typically considered difficult to maintain, repair or replace and are critical to the performance and safety of the structure.
Reason for the Standard Change
- There is common misuse by homeowners and contractors using Above Ground treated material in Ground Contact applications.