The Rot Doctor


Subject: Travel trailer rot
Date: Fri, 07 Jul 2000

I have an Award travel trailer with some wood rot. The trailer is constructed of built up panels which are then screwed together. The floor is of the same construction and I have two places where there was water intrusion. The floor is made like a sandwich with marine plywood used for both top and bottom sheets. The method of sealing the side walls and the floor was to use a clear silicone sealer. The sealer has started losing it's bond to the wood and water is starting to get into the seam area. I think your products would be the right choice and need your help to determine what products and in what quantities are required.

There are two areas where rot has progressed to the "punky" stage. Both are in the bottom sheet of the floor. I hesitate to remove the bad material as it would be difficult to access the area above. I am thinking the injection process might work for these areas and/or the spray process. Once the areas are treated, I am using metal sheeting to strengthen the area up. I could drill holes through and use stainless steel bolts to secure things. The area involved for this is about 4 sq/ft. One other spot is where the battery box was installed. The area at the bottom of the opening was subjected to water intrusion due to improper sealing. This resulted in rot to two sections of wood. I have removed the first piece (about 7/8" x 1 1/4" and find the wood below it is punky but sound. I feel this area could be treated with your CPES material by brushing.

I would appreciate your recommendations on this repair to a really fine trailer and look forward to your response.
Thank you

Hugh D.


If the floor wood is reasonable dry, then you are correct in assuming that the injection of CPES (Clear Penetrating Epoxy Sealer) would be the most appropriate solution. If you pump in the CPES until the wood will absorb no more (that is, it's running back out on you) the chances are that it will penetrate to the maximum distance of the deteriorated wood. Another step, if you are concerned that you might not be reaching the full extent of the bad wood, would be to drill small access holes down from the top and inject the CPES through these. Once again, in the wood it will migrate rapidly to all deteriorated areas.

I would do this twice, about a day apart. The second application will require much less of the CPES than the first application.

For your battery-box area I again think you analysis is right on. Liberally brush the area with the CPES, give it a day or so to vent the carrier solvents, and then put a new piece of wood on top to replace the piece you removed. You should also treat the new piece of wood with the CPES, especially the end-grain areas, and you should pilot drill fastener holes (if required) and treat them with CPES before installing the nail, screw or bolt. This will give you long-term protection for the new wood.

Try not to re-seal with silicone. Everyone uses it because it's readily available and it's cheap, but it's a lousy sealant. 3-M makes a line of products which are sold in marine stores. I'd recommend the 4200 or the 5200. They're about $12.00 a gun-cartridge.

I would guess from what you describe that you would probably need at least 2-quart unit of the CPES. You might need more. It's hard to tell with plywood; it sometimes absorbs a surprising amount of the liquid, which is just fine because you're protecting the wood. If you have CPES left over and it is unmixed and kept in the cans, it has an indefinite shelf can use it elsewhere, perhaps.

I don't think you will need any of our other products -- the CPES should do the job.

Come on back if you have further questions.