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Approved Integrally Treated Composites
WDMA I.S.4 Approved Integrally Treated Composites

The Window and Door Manufacturers' Association has received requests from Licensees under its Water-Repellent Preservative Treating Certification Program for approval of various in-process preservative treated wood composites. Accordingly, for the benefit of these licensees, WDMA has reviewed tests of these treated wood composites. These tests revealed that the following integrally treated wood composites meet the requirements of WDMA I.S.4, Industry Standard for Water-Repellent Preservative Treatment of Millwork, and are acceptable for use under the WDMA Water-Repellent Preservative Treatment Certification Program.

Trade Name
Active Ingredient(s)
StrandGuard® TimberStrand® LSL
Zinc borate(a)
Weyerhaeuser, Hardwoods & Industrial Products

(a) 2ZnO • 3B2O3 • 3.5H2 O ; ref. AWPA Standard P18

(b) Expressed as percent by weight, dry wood fibre

Note:  This listing is not intended to be a complete list of integrally treated wood composites that conform to WDMA I.S.4, but rather, it is a list of those products that have been submitted to WDMA for review and approved.  WDMA makes no claims as to the availability or suitability of the in-process treated products listed.

Weyerhaeuser, Hardwoods & Industrial Products http://www.woodbywy.com/trus-joist/industrial-applications//
Sarah Fulcher
(206) 539-4325