Sub floor problem

[Ed & Diane]

I have a dry rotted sub floor, p.s., rear corner. It looks like OSB board, I can spoon it out and it might pass as granola. It is visible looking through the engine door, below the right side engine door hinge. Has anyone replaced the sub floor back there? Inside, it is the floor of the closet, I can stand on the floor in the closet and feel no softness, but the very corner is boxed in to allow for the hinge and the air intake. From the engine door side, the subfloor sits on the rear most bulkhead frame. The corner edge had been caulked and taped, but tape had lost it's tackiness. And possibly moisture came in that way, or possibly water came through the air intake and found a way to the subfloor.

The simple fix is to cover it with metal flashing and caulk the edge and hope it gets better. To replace it, the board would have to span to the next bulkhead, at the battery compartment. Or I could maybe add an intermediate brace.

There are obvious challenges to sandwiching a panel between the steel frame and the finished floor above.

Has anyone tackled this kind of repair? It is only punky over the frame to the edge of the air intake boot, maybe 5".

[ALPINEER]

Hi Ed & Diane,

I have done many repair jobs on rentals, and sometimes tearing out and replacing is just not doable. An example of this is corners of window sils. Minwax makes a product called Wood Hardener that I have used many times. Do not scrape or spoon out the rotted wood. Lightly brush onto the existing rotted wood, several coats and let it penetrate. It will get as hard as new wood. Maybe this will work in your application.


Frank
03, 36' ISL 400

[Basil Shannon]

Nobody else jumped in on this one so I will.

If water gets behind the outside covering of the OSB looking sheeting WRV used, it can't get out & the wood will turn to mush. See pictures of severe damage caused by poor sealing.

Due to the difficult location, the metal flashing, aluminum (or?) might work well. Some ideas:
1) Cut away the outer covering in the damaged area and remove the rotted wood "granola". All it does is collect more water and cause more rot.

2) Soak the exposed good edges of wood with polyurethane (or?????)

3) Cut your flashing about 3-4" larger than the damaged area. Should slide over the rear bulkhead frame if possible.

4) Assuming area has access to attach with screws, drill holes in flashing at edge.

5) Drill several holes in flashing for injecting foam sealant and for checking flow throughout cavity.

6) Clean and paint to match existing structure. After paint is dry, mask.

7) Apply liberal coat of Dicore (or? sealant) to seal under flashing area to be screwed and back at bulkhead frame and install flashing.

8) Mask/protect area below/around work area. Could get messy & the spray insulation is STICKY!.

9) Rubber gloves! Inject spray foam insulation in holes and watch for flow coming out other holes. This stuff should expand to fill and seal the area from within. Let it set up.

10) Remove masking from flashing.

11) Check for sealing all around.

Monitor area beyond repair for further damage.

Pictures?????

[EngineerMike]

IIWMI'd just have EngineerAnnie plug the hole w/her finger while I'm driving (like Basil does in the photo above).

Coach floor is a sandwich w/OSB on top side, foam board in middle, and OSB again on bottom w/a plastic sheet cover. I have some dry rot in basement soffit above tank compartment, maybe 18" long & 5" deep along PS edge of coach where there is apparently a bad flashing spot along the side wall. I intend to dig out the bad wood & plate over it w/plywood & screws along the edge of the patch, and to fix the flashing w/sillycone.

[hax]

West Marine has a product "git-rot" epoxy that solidifies rotten would and can be used next to styrofoam /fiberglass. It penetrates and soaks into the granola and after several coats it will be solid and water resistant.

[TexasTom]

X2 on the git-rot

Used it on boats with great success. Don't remove the wood because this stuff replaces the moisture and penetrates the wood with a hard glue type stuff

[BFlinn181]

As others have said, the floor is most likely a sandwich of OSB, Foam board, OSB again. Since you don't find damage in the closet, it sounds like it's the bottom OSB that's crumbling. GitRot is a good product, it's like watered down epoxy that soaks into the wood fibers and hardens. If you can get it into the rotting OSB, you might stop further decay. Since it doesn't seem structural in that corner, I'd treat it and then cover with aluminum flashing and caulk the corner to prevent future water entrance. Make sure the water isn't coming in the air intake vent or the hinge. I wouldn't just cover it, treat it to stop the rot from spreading.