The Rot Doctor


Subject: Plywood core rot under teak
Date: Fri, 07 Aug 1998

Dear Dr. Rot:

I am considering the purchase of an 18-year-old fiberglass sailboat. The deck is 3/8" strip teak planking laid over fiberglass and 3/4" plywood. The structural decking is attached to wood deck beams glassed into the hull. Water has been leaking through the teak seams and screw holes for several months causing some rot in the plywood below. One marine repairman said the teak needed to be taken off and the fiberglass sealed with epoxy and a no skid surface. He also said to forget replacing the teak as it would just lead to more leaking in the future. What recommendations do you have for this kind of problem? Does the plywood decking need to be thoroughly dry before your CPES can be used effectively?


Geoff S.


Well, if the wood under the glass (which is under the teak, right?) is beginning to rot, then the repairman's suggestion is a non-solution. The wood will continue to rot no matter what you do to the layers above it. The "structural" solution to the problem would be to tear everything off and start replacing wood, but that is such a major project it hardly seems worth while buying the boat.

What I would do is 1) inform the owner or broker of the problem, the magnitude of the repairs, and seek a substantial discount on the boat price; and 2) assuming you get the boat at the price you want, I'd then remove the screws/fittings that are thought to be leaking, allow some time for the wood base deck to dry, and then inject all the Clear Penetrating Epoxy Sealer (CPES) that the wood will absorb. Give it a couple of weeks for the carrier solvents to evaporate away, and then re-bed the screws with a good, waterproof compound.

Have you cured the rot problems? Not necessarily, because you have no way of getting in there to evaluate the CPES injection process. Have you partly solved the rot problems? Yes. The CPES will flow and penetrate and be absorbed into all wood that is soft, punky, and reasonably dry. It will harden and that wood at least will likely not rot again. Following that, you just keep your eye on the subdecking and if you spot additional rot, then your undertake the same process again. This takes some time, but is a lot simpler than ripping up decks, and you get to keep the teak. Re-sealing teak deck seams is not especially fun, but doing it right with good materials can give you a lasting solution.

Come back if you have additional questions.