Use of Topical Treatments with Engineered Wood Products
The application of paints, stains, or other topical treatments to Engineered Wood Products (EWPs) may be requested by designers, builders, or homeowners in order to enhance certain properties such as appearance, mold resistance, insect resistance, flame spread rating, or fire resistance.* It is the responsibility of the topical treatment manufacturer and applicator to first ensure suitability for such treatment with EWPs prior to their use. The method(s) of verification and/or conditions of acceptability are also the responsibility of the topical treatment manufacturer and applicator.
Typically, a topical treatment will not cause damage to EWPs if the treatment is applied without pressure or soaking, and does not contain chemicals that are detrimental to wood or EWPs and their components. Chemicals that are known to be detrimental to wood and EWPs include, but are not limited to:
- Strong acids or oxoacids (e.g. hydrochloric acid, sulfuric acid, phosphoric acid, acetic acid)
- Salts of oxoacids (e.g. monoammonium phosphate)
- Alkaline solutions
- Oxidizing agents (e.g. hydrogen peroxide)
- Enzymes (e.g. cellulases, lignase)
- Salts of metals (e.g. salts of manganese, iron, chromium, iron chloride)
In addition to the above, the topical treatment manufacturer and applicator are responsible for:
- The efficacy of any treatment for its stated purpose when applied to EWPs
- The adhesion of any treatment to each type of EWP
- The potential short-or long-term corrosiveness of any treatments on metal fasteners or other hardware in contact with such treatment
- The short-or long-term effects of any treatment on EWPs
Product Markings:
Treatments which obscure identification marks on an EWP may make identification of the manufacturer
impossible. If product identification marks are not clearly visible, documentation should be required
verifying manufacturing information. Other requirements may also apply and users should first consult
with the EWP manufacturer and its certification agency.
* For more information regarding establishing equivalent fire performance for prefabricated wood I-joists see “Establishing Fire Equivalency for Floor Framing Members to Unprotected 2x10 Dimension Lumber or Equal-Sized Structural Composite Lumber” published by WIJMA at https://www.i-joist.org