Avionitis

[Salty]

My trailer has Avionitis. More commonly referred to as floor rot.

I was afraid of this, so I half expected it when I pulled out the carpet, and lo and behold, there it was. So now off to re-read other forum members experience with floor replacement.
When I probe it with the tip of my knife, it doesn't sink in, so maybe I caught it in time, and the repair isn't too bad.
Rained on me all day, so no cover coat on the koolseal.

[Salty]

Nope, not an easy fix. Two of the boards, sleepers I think they are referred as, are rotted as well.

[silverloaf]

Hmmm...this looks familiar. I learned the vinyl flooring traps a lot of moisture. Any leakage or weeping from the exterior gets sucked up by the edges of plywood like a sponge. I found the top layer of plywood and the 2x2 perimeter edge gets the damage first. Once the plywood gets wet under the vinyl, it never dries out. A real "tell" is when the vinyl curls up around the wall edge.

When you peel away the vinyl floor and and top wood layer near the curve, you will likely run into a sandwich of plywood. It is the same thickness as the foamboard. It is cut at a 45 degree angle facing inside, then wraps under the curved corner and butts up against the outside skin.

Now the tricky part: Not only is the wall/floor curve an ellipse, but the sandwich ply is cut as a 12 degree angle to conform to the skin. It took me 2 cardboard templates and a plywood mock-up to clone this curved piece under the curve.

So..if your're trailer is constructed anything like mine, grab a vibrating saw, angle grinder, prybar and a sense of humor.

[KYAvion]

What a pain.

I wonder how critical these corner sections are since they're not subject to foot traffic?

[Salty]

Vibrating saw is what I lack, my sense of humor is being tested.
I suspect the leak that caused the problem is at the awning brace mount. I'll look at that tomorrow.
I pulled the lower 6" skin already. Tomorrow I'll remove the Credenza and the arched skin. Might pull the pan underneath to have a look from the bottom.

Silver, I have no doubt that my trailer is built the same as yours. The model years are too close for a major redesign to have occurred so close to the end of production.
Any tips on how to remove that vinyl flooring?

[silverloaf]

For the right front corner, I decided to work down from the inside before dropping any skin or belly pan.

I had pulled off the lower skin and belly pan in the rear to replace large section of floor. It was a PITA to refit, screw and rivet everything back into proper place.

When I peeled away the top ply and foam board in the right front corner, I found no rot in the lower ply.

I removed everything around the curve that was rotted and inserted new material. I put a coat of wood gardener on the lower ply first.

I wouldn’t expect there to be much difference in floor construction techniques between your 87 34V and our 88 30P.

Regarding the vinyl flooring, I removed anything loose or wet. The dry stuff is practically welded to the upper ply. I purchased some paste-type filler/leveler . I’ll screed a layer over the new top ply that is flush with the vinyl. I just want it flat for the new vinyl plank flooring.

[KYAvion]

How did you attach the c-channel to your wood in the corner? Did you also remove the rubrail and fasten from the outside too?

Also, what is the corner piece resting on?

[KYAvion]

Another question. Is straight wall section sitting directly on the frame, or the 2x2?

[silverloaf]

The floor assembly is not directly attached to the main box frame. There are flanged wings that are welded to the main frame. The wings are not necessarily placed parallel with the steel floor supports that span under the floor. In the picture below is an example of one of these wings projected out from the main frame

The floor is bolted through the wings using elevator bolts. (see below). The c-channel is secured to the floor assembly with hex-drive screws; maybe 2ft apart. I used an angle grinder to sever the bolts and screws.

In the right front corner, there is an elevator bolt directly below the front edge of the side window. The wall and floor are straight at that point. The floor is bolted through the wing. If your trailer is like ours, you can gain access to the hole in the wing from inside the front compartment when it comes time to install a new fastener.

The piece of angular sub-floor (shown earlier) is just a filler to account for the curve. The 2x2s (1-1/2" actual) under the straight wall sections merely butt up to the curved filler. The curved filler is also 1-1/2" thick; it is built up with 2 pieces of 3/4" ply. From what I observed, it rests on no steel or nor provides any structural support by itself. The shape of the filler is an ellipse and curves downward 10-12 degrees to conform to the outside skin.

I did not replace the entire angular filler. It sawed it back to good wood and used construction adhesive & a few screws to bond it to the remaining filler and lower ply.

I did all repairs to the corner from the inside. I found no benefit for removing exterior skin sections for a localized re-build. Replacing steel below would be a different matter.

I glued and screwed the filler to the top and lower ply of the floor; It's strength in numbers. This assembly gets additional stiffness when the c-channel with walls are screwed to the floor.

Note: This is where the vibrating saw really shines to save or excise any piece of wood without tearing up what you want to keep.

Regarding the lower rub strip, I removed the vinyl screw cover. I removed the screws securing the aluminum carrier a foot or so beyond the repair area and left it in place. These screws go into the side edge of the floor. If one is concerned that the lower skin might separate, bridge the skin with tape until final re-assembly. I didn't need any tape; stubbornness held it in position.

Once the floor was removed (except lower ply), I ground down the heavily-rusted staples securing the lower exterior skin to the floor using my angle grinder. After replacing the floor section, I installed new screws for the carrier. The screws go through the two layers of skin and into the side edge of the floor.

[silverloaf]

Picture of elevator bolt. I used a standard 3” long bolt and wide washer for replacement.