Floored, Part 1

It would seem that the hot water tank in my trailer has been leaking for a number of years.

When we got the trailer last year, I noticed a soft spot in the floor near the tank, and while the tank was out at the shop being repaired, I decided to take a closer look. What I found almost made me wish that I hadn't. Ignorance is bliss, after all.

First off, a note about construction. This vintage of RV isn't made of prefabricated panels of exotic materials. It's just wood and tin. It's basically built like a house, only using lighter, cheaper stuff. On one hand, it means it's very vulnerable to rot from water damage. On the other hand, damage can be repaired more easily than more modern RVs, since materials are available at any building supply store.

The floor is built like a layer cake. On top is a layer of linoleum. Under that is a layer of 5/8" plywood. Then a layer of 1x2" lumber, spaced 24" apart, with fiberglass wool insulation in between. Then a layer of cardboard. Then styrofoam, and finally a sheet of aluminum.

What the plywood looked like, under the lino

As I peeled up the lino, I discovered that the water damage had dissolved the glue, and the lino came up easily. Beneath that, the plywood subfloor was still saturated with water. I cut away enough lino to find dry plywood, set a shallow depth on my circular saw, and started cutting.

Since I didn't know how thick the plywood was at this point, it took me two or three tries to get through the floor. I eventually found out that the plywood was 5/8" thick. I also found that the joists were 1x2" lumber, and that they were also pretty rotten. In fact, the ones that weren't rotted black from water damage were dry-rotted. However, it turns out that most of the structural integrity of the floor comes from the plywood itself; the lumber served only as spacers to keep the plywood off the layer of styrofoam.

Beneath the plywood, I found soaking wet insulation.

Under the plywood, between the joists, I found a layer of fiberglass wool insulation. This, of course, had managed to soak up water like a sponge, so I pulled up what I could reach and threw it out. Under the insulation I found a layer of cardboard which was wet with water. Tapping on the cardboard made a sound that made me think that there was a layer of styrofoam underneath, and some measurements indicated to me that there wasn't anything else between that and the layer of aluminum on the bottom of the trailer.

The cardboard beneath the insulation. Also wet.

The cardboard is continuous under the joists; at this point I didn't want to dig any further into the floor. I figured that the styrofoam would be impervious to water anyway, and I didn't want to cut holes in the exterior floor anyway. I dropped a fan in front of the mess to dry it out, and left it for a couple days.

From this I learned a couple important rules about repairing water damage:

1. There's always more rot than you think: You have to be prepared to remove more than you expected. The rot is easily hidden by the waterproof top layer.
2. It's still wet in there: most of the materials that make up a floor absorb water. The longer you've had a leak, the more water will have been soaked up by the materials. And they don't want to let it go. My trailer had been sitting for a couple weeks after I'd stopped the leak and mopped up the visible water, but the wood had soaked up so much, and the lino had trapped it there, that I was still pulling up soaking wet wads of fiberglass and pulpy handfuls of what used to be plywood when I started taking the floor apart.

I also learned an important lesson about water damage. Fix it as soon as possible. Tear it open and dry it out before it starts to rot, or your problems get worse by orders of magnitude.

It looks bad, and at this point I'm faced with two options. One will give me a serviceable trailer, if I'm willing to spend money and do some hard work. On the other hand, Beltane is fast approaching, and that's traditionally celebrated with a big fire. Stay tuned to see what I decided to do.