The Rot Doctor


Subject: wellcraft rotted deck (pt. 2)
Date: Sun, 08 Aug 1999

Thank you for the timely response doc,

Since I mailed you the first time I ripped up the deck and found 90% of the stringers in good condition but a few had water rot from the top down maybe a quarter of an inch. I would like to avoid replacing the stringers since they are glassed to the bottom of the boat and save them hopefully if you have a product that could. I now agree with you after seeing the old deck rotted beneath the glass that was covering it. Here is my last questions in order to complete my project:

1. what product do I need to save the stringers and do I have to cut the top 1/2 inch off and replace because of rot? I was thinking if I could control the rot and not let spread I could place support 2x4s on either side of the stringer and screw them together with the old stringer in the middle and use the 2x4s to support the deck. (this is only in a few stringers of the boat and there is enough good wood in the stringers in order to support the 2x4s)

A 1/2" of rot is not significant. Make sure the wood is dry and simply apply CPES (Clear Penetrating Epoxy Sealer) generously to the top of the stringers. Let the wood absorb all that it will. If there is missing wood or you wish additional strength you could apply Layup & Laminating Resin on top of the CPES once it cures (3-4 days).

You may not need to even sister (support) the repaired stringers. The epoxy is very strong and does restore strength to the wood. But then it wouldn't hurt anything either. If you do sister the existing stringers, be sure that the new wood going in is treated with CPES, especially the edges and ends. after it is cut and before installation.

2. Will treated plywood work (like the wood you purchase for outside decks) or do I need to buy a special marine wood. If the treated wood works do I need to cover it with you product prior to laying it in the boat?

Exterior grade plywood will work. Treated is okay, but no guarantee, since the quality of the treatment process varies greatly. If it were me I'd just buy plain exterior grade ply and treat it with the CPES. If you buy treated, it too should be CPES-treated so you can be sure you are getting truly protected wood.

3. I like your theory on the wood needs to breath but what do you think about glassing the seems of the new deck in order to give support and to keep the deck level in the coming years.

Glassing seams is okay, but be sure to use our Layup & Laminating Epoxy Resin, not polyester resin. Poly resin does not stick well to epoxy treated wood, nor is it nearly so strong. With glassed seams there will still be plenty of area for the wood to breathe.

4. How much of your product do you think I need to cover both sides of the new deck(probably (4) 4x8 sheets total)

You can figure that CPES spreads 200-300 sq feet per gallon on new wood, although you will be using a bit extra getting it into the edges. If my math is right 4 sheets of 4 X 8 ply would be 256 sq ft, plus whatever extra you need to get it into the edges. You won't be applying the CPES until the wood is cut and ready to install -- right? So, that would be at least two of the 2-quart units of CPES.

If you glass the seams, you're probably looking at a 2-quart unit of the L&L Resin to apply to the glass tape. That may be a bit more than you need, but it'll keep a couple of years if unmixed and kept in the closed cans and kept from freezing.

thanks for the timely response

Okay, sounds like you're getting there. Come on back if you have additional questions.