My deck has a cantilever of about 4 feet from the girder to where the stairs attach, and the stairs tend to have a bit of a spring in them when you walk up. I want to solidify it a bit by sistering some joists in that area.
I've been trying to decide what adhesive to use, if any. I think nails themselves would be a solid repair, but the extra strength from some adhesive is also a good thing.
I've found that PL 400 (or other polyurethane) adhesive is advertised as compatible with wet pressure treated wood, and as being waterproof, and I'm leaning towards that.
The deck is about 5 years old from what I understand, so the joists are certainly dry. I'm worried about using adhesive in the repair and having the shrinkage of the greener wood delaminate from the adhesive on one side of the wood. I'm also worried about the board drying unevenly with one side in contact with dry wood and the other in the open air, I think the wood may try and cup a bit, backing out my nails. Maybe I should dry the wood for a few months first? They don't sell yellawood up here in Massachusetts.
Would you use adhesive, or just nails? What kind of adhesive?
Edit: Message received on nails vs screws for exterior applications - but I'm most curious about the adhesives