Field testing of Millwork Formulations: L-Joint Results After 9 Years of Exposure in Minnesota

摘要

The origin of water-repellent preservative treatments for millwork was based on the knowledge that not all wood exposed outdoors would remain below the critical moisture level for decay. As the millwork industry has shifted away from the use of pentachlorophenol, other preservative active ingredients have been used. Much of the above-ground testing with L-joints has been derived from exposures with high to severe decay hazards to accelerate treatment differences. Data from a 9 year exposure in a moderate decay hazard zone show treatment performance differences for ponderosa pine finished with a modern polyurethane. The performance of treatments for decay prevention was: PCP>TCMTB>IPBC>Untreated Controls. As extensive decay has been noted in untreated housing window and door systems as early as 5 years in this moderate hazard zone, it would seem that the L-joint test is not necessarily an accelerated test for performance of unprotected wood.