W. CONSHOHOCKEN, PA — A proposed new ASTM International standard will offer guidelines for selecting wood substrates for the evaluation of the weathering performance of architectural coatings, such as exterior paints, primers and deck finishes.

The proposed standard, ASTM WK 32654, Practice for Selecting Wood Substrates for Weathering Evaluations of Architectural Coatings, is being developed by Subcommittee D01.42 on Architectural Coatings, part of ASTM International Committee D01 on Paint and Related Coatings, Materials and Applications.

According to D01 member Marek Gnatowski, the need for the proposed standard is the result of the growing complexity of wood-based materials used in architectural applications, techniques of architectural product finishing and the demand for high-quality coatings capable of performing on a wide variety of wooden substrates.

“Properly designed and tested coatings increase the longevity of architectural elements and reduce maintenance costs to building owners,” says Gnatowski, Technical Director and President, Polymer Engineering Co. Ltd. “On the other hand, forest resources that supply high-quality, old-growth solid wood to the construction industry for architectural applications are becoming scarce.”

In order to meet market demands, a variety of wood composite products have entered the market, such as gluelams, a variety of wafer boards, finger joint siding and composite trims. In addition, younger trees are now being used to make home sidings. Marek says the proposed standard will aid in the development of paint for these new lines of architectural products.

Once it has been approved, the standard will offer guidelines to chemists who are formulating new paint or other finishes for use with wood in architectural applications. In addition, end users will find the proposed standard helpful in comparing the performance of a variety of architectural finishes.

Gnatowski also notes that material covered by ASTM WK 32654 is widely used as finishes for home sidings and trims, as well as other architectural elements such as fences, decks, garden furniture, gazebos and playground equipment.

All interested parties are invited to join in the development of ASTM WK32654. For more information on becoming an ASTM member, visit www.astm.org/JOIN.