This technique can also be used for small rotted floor areas as well.
Use the penetrating epoxy, as Brian describes below, to stabilize the
soft wood. Then cover any holes with standard epoxy and fiberglass cloth.
That is what I did in my '77 Sovereign,
Dave
> Hello all,
>
> I am in the process of restoring and re-tiling the floor on my '56
> Caravanner. I have just repaired the area aft of the doorway using a
> technique that I think might be of interest to others on the list.
>
> Since the interior of my Caravanner is pristine, I didn't want to
> remove the interior panels in order to access the areas of the floor
> under the U-channel. I have only two or three bad spots on the
> perimeter of the floor, and I am trying to repair these with as little
> disturbance of the trailer interior as possible.
>
> When I pulled the tile up to the rear of the entrance door, I found
> that the wood wasn't rotted, but had been water-soaked so long that
> the plies had separated. On small areas this condition is easily
> corrected by drilling 1/8th inch holes about half an inch apart into
> the wood (but using a stop collar on the drill to avoid going all the
> way through), then soaking the area with thin marine epoxy. Pushing
> down on areas of the floor affected as the epoxy is poured over the
> holes will help spread the epoxy throughout the layers of plywood as
> it seeps down the drilled holes.
>
> When the wood is saturated (it will hold a lot of epoxy), put a couple
> of layers of waxed paper over it and a heavy weight to hold the plies
> together. Remove the wax paper as soon as the epoxy hardens to the
> touch. The resulting floor will be hard as steel and impervious to
> water damage in the future. I have corrected a couple of small (8"x
> 8") areas this way and had excellent results.
>
> The new technique I tried involved an area about 18" long under the
> U-channel aft of the entrance door. This area is beneath the front of
> the closet and the factory heater in my Caravanner.
>
> I removed the front of the closet and the heater. I then cut out the
> bad section of floor under the U-channel and out into the good floor
> about a foot away from the wall with a spiral-cutter set to the depth
> of the plywood. I was then able to reach back under the U-channel and
> remove all of the bad wood there. The fasteners were still good, and
> still stuck down from the U-channel.
>
> I then cut a piece of plywood 18" long and five inches wide, and
> pushed it up under the U-channel from beneath (this is all done from
> inside the trailer with the belly skin undisturbed). When I pulled
> this new plywood out, the tips of all the fasteners hanging down from
> the U-channel had left impressions in it. I then used a 1/4" drill to
> drill holes through the new plywood where the fasteners had marked it.
> Now I could push the new strip of plywood all the way up to the base
> of the U-channel to check the fit. The old fasteners went through the
> new holes I had drilled.
>
> Next I coated the edges of the new plywood and the drilled holes with
> epoxy and let it soak in and set. Then I put a couple of layers of
> masking tape on the bottom side of each of the holes I had drilled
> (forming cups), and filled each cup with epoxy. (Since I had coated
> the sides of the holes with epoxy, this new epoxy couldn't soak into
> the wood.) I also put a thick layer of epoxy on top of the wood, and
> fitted the wood strip in place under the U-channel. As I pushed up on
> the wood, I felt each fastener punch through the tape, and I tried to
> keep the tape tight around the fastener so the epoxy would not run
> out. I rigged a system of levers to push the plywood tight up against
> the U-channel and let it set.
>
> When it was done, there was a two-and-a-half-inch ledge of wood left
> sticking out from the U-channel at floor level. I weigh 225 and I
> could stand on the ledge with no deflection of the wood at all. It was
> then a simple matter to screw and epoxy a plate beneath this strip and
> drop in the new floor section.
>
> Since marine epoxy sets up as an extremely hard solid, I feel that
> this repair has all the structural integrity of completely removing
> the interior walls and putting new fasteners through wood. Even if the
> fasteners had rusted away, I think that putting several course screws
> up through the U-channel from below and then setting them in epoxy the
> same way would have a similar structural integrity. Once the epoxy
> sets, the screws can never move, and can never rust.
>
> It seem complicated, but repairing the wood under the U-channel this
> way is relatively easy, and the main advantage is that the interior of
> the trailer is untouched except where cabinetry has to be removed.
> Maybe this technique will help some owners who can't face removing
> interior panels and/or belly skins to fix the floor.
>
> Brian Jenkins
>