This week’s question comes from Brian. He writes:
“Quick question on joining treated pine – I would like to face glue surfaced 2×6 treated pine boards. Does the fact that i am using treated lumber reduce the strength of the joint or make the glue less effective somehow? This is for an application that will have to be waterproof.”
My reply is actually an excerpt from an article I found a while back from Iowa State Univeristy. Full Article Here.
Deposits on the surface of treated wood present problems in gluing. Oil-type preservatives typically present more problems than waterborne treatments. Wood treated with very high retentions of creosote or pentachlorophenol in heavy solvents is essentially non-gluable. Low retentions of penta in light solvents may be somewhat more readily glued than wood treated with creosote. Wood treated with waterborne chemicals usually can be glued without major problems, if properly dried. Planing or sanding the surface before gluing is recommended to enhance bonding. Select the adhesive appropriate for the exposure condition among conventional wood adhesives. Only resorcinol resin glues provide completely waterproof gluelines with wood; urea resin glues and polyvinyl resin adhesives generate only modest water-resistant glue bonds. Some types of elastomeric construction adhesives offer good resistance to moisture and are much more tolerant of high wood moisture contents and low temperatures than conventional wood adhesives.
If anyone has anything to add, please do so in the comments section. I personally have very little experience gluing treated wood.