UPDATE: This article was revised to better reflect how the revised AWPA standard may affect building codes and to clarify when changes might take effect.

If you build outdoor wood decks, there are some changes coming down the pike. The American Wood Protection Association (AWPA) is about to publish an update to its AWPA Standard U1 for preservative-treated lumber. When the new standard is published as part of the AWPA's 2016 Book of Standards (probably in May or June), it will include revised language addressing the treating chemical concentration (called “retention”) that is recommended or required in lumber used for deck framing, including treated wood posts, beams, and joists. In some situations, the new edition of the standard will call for “Ground Contact” levels of treatment, rather than the lesser “Above Ground” level, even for wood that is not in contact with the ground. The scope, timing, force, and effect of the revised AWPA Standard, however, is a topic of debate within the wood treating industry, and the practical implications for deck builders are still unclear.

The International Building Code (IBC) and the International Residential Code (IRC) — the basis for state and local building codes in the U.S. — both reference AWPA Standard U1 in their requirements for deck construction. But the 2016 edition of Standard U1 will not automatically be enforced at the local level, until the building code itself is updated and new code versions are adopted by state and local governments. Brian Foley, an engineer and building code official with the Fairfax, Virginia, building department, is a well-known authority on deck construction who was instrumental in past years in the effort to evolve new structural requirements to make decks safer and more durable. But Foley told JLC: “Until this [AWPA Standard U1] change makes its way into the Virginia code, we cannot require it. I will assume the market (i.e., Lowes and Home Depot) will slowly correct itself by selling ground contact lumber.”

Understanding the practical significance of the AWPA Standard U1 change, in terms of local code enforcement, is made more complicated by the fact that there are two ways in which treated wood products currently gain acceptance by the IRC and the IBC. One path to code compliance is for the material to be “standardized” through a listing with the AWPA, a process that requires product producers to perform documented standardized tests and to undergo a review by AWPA committees. Those reviewing committees typically include representatives from the listing company’s competitors, as well as any other interested parties who make the effort to become involved in the process. The other pathway to code acceptance is to obtain an Evaluation Service Report (ESR) from the International Code Council Evaluation Service (ICC-ES). In the ICC-ES process, the same AWPA test methods and standards still have to be applied and met for the product to gain recognition. However, the technical review is conducted by independent experts rather than by an AWPA committee, and many details are kept confidential by ICC-ES. In recent years, several new wood treating methods — including, for example, the “micronized” copper azole and copper quaternary treatment formulas — have chosen the ICC-ES pathway. Those formulas, and the lumber brands involving them, qualify for code acceptance only if they keep their ESR paperwork current. But the brands that are “standardized” within the AWPA system are considered code-compliant as long as they continue to meet the AWPA standard.

The ICC-ES Acceptance Criteria for Proprietary Wood Preservative Systems, AC326, was revised in mid-2015 to reflect the language of the upcoming 2016 AWPA Standard U1 (click here to see relevant language), even though the new AWPA Standard has not yet been published. Companies whose product requires an ICC-ES have been advised that they have to “requalify,” ICC-ES official Michael O’Reardon told JLC: the manufacturers have until mid-2016 to provide ICC-ES with documentation for compliance with the revised AC326 in order to receive a new ESR. When that deadline is reached, the old ESRs will expire. So for those treated wood lumber brands, the practical requirement to comply with the new provisions of the 2016 AWPA Standard U1 may arrive as early as this summer, even though building codes themselves may not have changed.

Mike O’Reardon of ICC-ES told JLC that in his view, this language in the new AC326, and in the new AWPA Standard, is generally considered ambiguous enough to allow some wiggle room in practice. Whether a piece of wood is difficult to replace or critical to structural performance can be considered a judgment call in the field. And so Reardon said that in his view, the AC326 language does not imply that all deck framing must be treated to Ground Contact standards — only that some of it should.

And of course, enforcement in the field of the revised AC326 and the new installation instructions it requires, like enforcement of the AWPA Standard U1, is in the hands of local code officials. Given that the revised language in both documents is open to various interpretations, code enforcement in the field may also be inconsistent. You certainly cannot assume that Ground Contact will be required for decks in your location. For example, Fairfax, Virginia, code official Brian Foley says his organization is treating the new language in the AC326 as a voluntary choice by companies who choose to apply it. Until Virginia code itself is amended, Foley told JLC, his office will not enforce the revised terms in AC326.

What does this mean for builders, remodelers, and deck contractors? Will the product mix on shelves be changing? How long will it take for this change to happen? And will code enforcement in your local area change? The answers to those questions depend on your local code authority and your local supply chain. Over time, the product mix on shelves may change to make Ground Contact lumber easier to find. And code officials may begin to look at deck plans and require Ground Contact lumber if, in their opinion, the lumber meets their definition of being critical to the safety of the structure, or difficult to replace in case of premature decay.

Lumber retailer Tony Shepley, of Shepley Wood Products on Cape Cod in Massachusetts, has already made a company-wide decision to supply only Ground Contact lumber to his customers. Shepley told JLC in February that he has seen the performance issues with "Above Ground" treated wood first-hand. "When you see a triple-laminated treated wood beam and deck joists decaying after five years nowhere near the ground, you know something isn't right," Shepley said. There's an up-charge of five to eight percent for the more heavily treated wood, he said. But he quotes Warren Buffet: "Price is what you pay. Value is what you receive." Said Shepley, "If you save six percent on the material but you have to replace it in five years, how can you say you got a better price?"

Regardless of how the supply chain responds, local code officials may not even be aware of changes in the phrasing of AWPA industry standards and ICC-ES acceptance criteria. One Cape Cod official told JLC in February that this change was not on his radar. Victor Staley, a building official in Brewster, Massachusetts, said in an email: “To be honest, Building Officials are often some of the last people to hear of changes to the National Codes and applicable references unless it comes directly from ICC or via some other mass mailing (e-mailing).... it takes time for information to get out and even more time to understand the change and sometimes even more time in figuring how to apply this information in our duties.”