I recently completed an insulation project in my attic using liquid nails and foam board, attaching the foam directly to the wall. I then added another layer of foam, using liquid nails to glue these two foam boards together. However, I later noticed that the liquid nails packaging warns against using it for foam-to-foam applications. My concern is whether the foam boards being glued together will stop the glue from curing properly. If I leave it as is, could the uncured glue eventually lead to moisture or mold issues? I'd appreciate any advice on this! Thanks!
3 Answers
If you're using rigid foam board, you’ll probably be okay. Liquid nails should dry and cure without causing mold issues. I’ve used it on foam in my container home for years with no problems. Just make sure the panels aren’t bearing weight just on the adhesive itself.
Just so you know, liquid nails can actually eat into foam if it's solvent-based. I suggest using a PL polyurethane glue instead. Also, don't forget to leave an air gap if you can; it helps with moisture issues. A closed roof system is fine, but you want to avoid foam touching the exterior if it traps moisture.
Thanks for the tip! It's a closed roof system, but now I’m extra cautious about airflow.
They actually make a foam-specific adhesive for this kind of work. Regular liquid nails can melt the foam rather than helping it stick. Just a heads up for next time! Also, if you've already used it, monitor the setup closely to be safe!
I hear you! It said safe for foam, but I'm worried about the foam-to-foam rule. Thanks for the heads-up, though!
Great to know! I’ll make sure to secure it with nails too. Thanks for the reassurance!