What can I use as waterproof putty for Azek lumber, exterior application? I am looking to mainly plug and cover (hopefully invisible) screw/nail wholes in Azek brick moulding, the same way I would use wood putty for in interior jobs on real lumber, like door and window trim, baseboard etc.

I have seen people water-sortof-proof using Quad door/window caulking but that's hard to get smooth. Is there a waterproof variant of regular indoor wood putty? Maybe epoxy of some sort?

  • sounds like Azek is a brand name ... talk to the manufacturer
    – jsotola
    Commented Jun 15, 2021 at 21:32

2 Answers 2


They have a filler for finish nail holes.

I’m not sure how it would do for countersunk screws.

azek nail filler


I use an epoxy filler I have around for repairing wood rot. You could probably use regular Bondo or equivalent. My siding contractor face nailed all the Azek corner and trim boards, so I ended up epoxy filling all of the holes, sanding smooth, and painting the entire boards white. (with a roller)

Painting composite trim actually causes it to shed water and dirt better than the "plain" factory finish.

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.