Forum Discussion

Homestead_or_Bu's avatar
Jun 19, 2016

Best Sealing? and DRY ROT- w/photos

Hey Everybody,
Boy, this gal could use your help. My new to me 1998 Coachmen C class has some significant water damage. I've got the roof sealed off really well, and thats looking good, but now the rest of the exterior needs attention, and there rare some problem areas. SO Im looking for best sealant recommendations, in general over all exterior, and specifically.

One ISSUE is that there is significant damage on the lower part of the panels that sit just behind the drivers door, and passenger door, meaning both sides, the drivers side being worst.( generator sits aft of it) The area below the molding (about1 foot) has the strength of cardboard, rather than wood that it once was. You can see what happens when I push on the panel in pics. The adjacent walls on the side of the vehicle shows no sign of dry rot. Only the front.
On these dry rot areas, the bottom metal trim is barely hanging on because with the rot, there isn't much to hang on to. I'm not sure if I should use a Sikaflex or Proflex ( sealant/adhesive) to hold it together and prevent further water entry. Or will doing so , just cause the area to get more brittle by binding it?
I wonder if i can shoot some epoxy or whatever in there to shore it up, because I can't see myself cutting it out and replacing it unless I had close guidance. And i know it would be cost prohibitive for a dealer to do it. Any ideas there?

Really want to take care of it, but not sure what my approach should be.

Next- can anybody tell me, by looking at pic, what kind of caulking was used on other near area seals? If its silicone, I heard that silicone is really hard to use anything over it, because not much adheres to it. I started to pull it off and thinking I could reseal with something like Sikaflex or PRoflex- using such over the whole exterior walls and seams...
Also I wonder what I should clean it up with - soap and water, mineral spirits...? Id rather use something non toxic, but that will prepare the surface well so I can get good seals.

Okay, Im hoping some of you experienced folks can lend a hand. I sure would appreciate it right about now.

Here's the photos-
  • Been there and done that on my 93. As the poster above stated OSI Quad is what I used to adhere the trim onto my new 1/4" plywood backing. First I sealed each side of the plywood with fiberglass resin then I used the Same resin to reapply the filon to the board using clamps and 2x4 to get it to adhere nice and smooth.
  • I had to replace the rear bottom panel when we first got our used RV. I was able to cut out the rotted panel and pull off the filon in one piece. Then I used some cedar boards and some cement board siding to get the same depth. I had good wood in the rear floor to screw it to. Then I glued the filon back on and eternabonded the corners. There are some pics on my photobucket site if you are interested.
    Pics
  • "Dry rot" of wood is somewhat of a misnomer; it's simply normal rot that has since dried.

    From what I gather, these panels somewhat commonly have rot problems. The proper solution is to replace the rotted plywood, rather than merely sealing what is there that's not structurally sound. For just the lower bits of these walls, that shouldn't involve a tremendous amount of surgery or dismantling the interior.

    It's hard to know what the existing sealant is from the pictures. It almost looks like it's the butyl putty/tape that is used under the corner moldings that is oozing out, rather than something applied afterwards. Thorough cleaning and trimming/scraping off of the existing material, whatever it is, and then applying something on the clean surface is how I would go about sealing the seams. I have generally used OSI Quad, which is readily available at Home Depot and Lowes and similar places and appears to me to be very similar to Geocel ProFlex. I would not really suggest Sikaflex as it's more an adhesive than a sealant and might be very hard to remove if you should ever need to do so.

    Acetone works pretty well as a cleaner for these sorts of things. Isopropyl alcohol can also work and is not as strong a solvent as acetone, which is sometimes helpful and sometimes not. You can find acetone in the cosmetics department (nail polish remover) and isopropyl alcohol in the first aid area (rubbing alcohol--look for 90 percent strength).