Rot Doctor


Subject: Rotting Plywood
Date: Thu, 14 Jan 1999

I am repairing an old Crest pontoon houseboat. Due to water seeping from the exterior decks into the cabin (a design flaw in this boat) a small corner of the plywood cabin floor rotted. I removed the rotted wood leaving about a 6 inch triangular hole. We have corrected the problem that led to the water getting in but now we need to repair the hole. It sounds like your product would be ideal for the perimeter of the rotted area—it is not large and since this boat is on pontoons, this wood will not be in the water. The bottom gets wet when underway, but a hole in the floor won’t sink us. It is inside the cabin so it is protected. It doesn’t have to hold much weight because it is in a corner. I understand the use of the penetrating epoxy but I don’t understand the filler. After I saturate the wood surrounding the damage, how do I fill the hole. I assume I have to attach a backing and put something in the void. Then does the backing come off after the filler cures?

You’re on the right track. Soak all the perimeter wood with the penetrating epoxy (CPES). This will preserve the wood and kill any rot fungi or reproductive spores that remain (and they do remain). Apply the CPES to all bare surface wood that is exposed around the hole. In all cases apply as much CPES as the wood will accept. Give it a few days to cure.

And yes, you do need the backing piece. After it is cut and ready to go into place, apply the CPES to it as well, especially the edges — again, as much as the wood will accept. Fasten it in place. Ideally, you would pre-drill the holes for screws or bolts, and those holes also should be CPES-saturated. Again, allow to cure. Now, you can go back over the backed hole and use our Fill-It Epoxy Filler to fill the void. The Epoxy filler can be sanded after it cures (about 24 hours). It will bond with the CPES-impregnated wood and give you a strong completed repair. By all means leave the backing piece in place.

Also, the exterior deck is 3/4 plywood with carpeting glued on. I plan to remove the carpeting and replace it with Dri Dek. Would it be beneficial to seal the deck with something under the Dri-Dek? If so, what about the leftover adhesive from the outdoor carpet? I can't imagine that it will ALL come off although I plan to use a belt sander on it. Can the epoxy be applied over some residue? Cosmetics are not important as the Dri Dek will completely cover the decks. I just want to protect the boat from rot. It is in remarkable condition.

CPES will penetrate around some remaining finish. If you in fact sand the deck you will remove most of the adhesive. And yes, an application of CPES will help preserve the wood. Coverage on this kind of flat surface application is about 300 sq ft per gallon. Apply the CPES generously to any cracks and crevices. Give it about a week before going back and applying the Dri-Deck.

My husband and I are just learning about this stuff but our repair sounds easy compared to the questions in this site. I had planned to use Git-Rot but your product sounds better. I would really appreciate any advice you can offer.

We’ll help you any way we can. Better leave Git-Rot alone — it doesn’t penetrate. No comparison to the CPES. Come back if you have more questions.