The project - roof

We knew the little trailer had some issues.

There was tar all over the roof, so obviously someone had at least suspected leakage. The roof had pulled away from the vents, and parts of the ceiling were wet. The contact paper had pulled away from the ceiling in a few places, and there were a couple of soft spots on the floor under the carpet.

For two newbies, this didn't seem so bad. It had an oven, refrigerator, double sink, toilet, shower with tub, sleeping for four (if two were kids). Seemed like a good fit for us and the price was right.

I've learned a lot about wood rot, water damage, and the two common types of mold (white crud, and black stains). More than I ever wanted to know.

As of this writing, I've done some major surgery to fix serious structural issues caused by neglect, damage, or water leakage. It's been about a month, and all things considered, I've accomplished a lot.

Roof:

Most sealants designed for RVs are incompatible with petroleum distillates. In other words, the tar had to come off. But first, I had to be sure the roof could hold me. The ceiling's been out for a few weeks -most of the wood came apart like paper, but the joists were solid. There was a big square of plywood (not centered side-to-side by the factory, for some reason) around the only vent - presumably to support an air conditioner. There was also a lot of space between the roof and the joists. Originally, it looked like the factory just laid fiberglass batting over the joists and put the aluminum roof skin on top. Over the years, the fiberglass collapsed, and things started to get loose.

I managed to slide pieces of plywood above the joists and under the roof skin. I have a path that matches the factory 1/2" piece, that spans all the joists front-to-back, with the exception of the curved roof section fore and aft. I plan to put a second vent a few joists back from the first, and would like to eventually get A/C in one, so on top of the 1/2 plywood, I slid two 10" wide pieces, makeing a 20" wide section that spans from the front of the existing vent to one joist back from the furthest point I would put a new vent. This helps the roof to slope away from the center, and it insures that I can support an A/C unit. It also means the roof will support me.

I also slid 1/2" insulation between the joists and the roof skin above the 1/2 plywood (but not where the 3/4" plywood is). Besides the insulating value, this helps to keep the crown of the roof with out the aluminum collapsing, but it has enough give that the roof would dent rather than puncture from impact. In the future (after leak testing), I will use 1 1/2 sheets of rigid insulation between the joists before puttting the ceiling back in.

Back to the tar. Well, it was more than tar. There was a mixture of old putty tape (easy to remove), tar, silicone caulk (PITA) and something I took to calling "caramel". I couldn't find a solvent that would cut whatever the caramel was, and it was tough. Tar is no fun under any circumstances. After much trial and error, and a battery of solvents arrayed against my new enemies, I settled on the following process which, although time consuming, worked pretty well:

1) Heat gun. This softens the tar and makes the caramel a little easier to scrape off. I used the heat gun and a putty knife to scrape off the top layer of crud.

(note, the aluminum roof has a texture to it. Inconveniently, it makes removing sticky, gooey, crud even more problemmatic)

2) Goof Off. It's a combination of Xylene and Toluene. Nasty stuff. Laquer thinner worked, but it evaporated too quickly. I used a stainless steel wire brush from the welding dept at Home Depot, a container of Goof Off, and a box of disposable "super rags" that HD sells. The process is to dip the wire brush in the Goof Off, scrub the crud until it softens and dissolves, then use the rag to soak up the material before the Goof Off evaporates and redeposits it onto the surface.

This actually works pretty well, although it takes a few applications to get down to clean metal. Oh, and it's hotter than heck on the roof already without leaning over a heat gun and fumes.

So the roof's all clean, and it turns out I can't find any leaks. Well, except for the holes around all the vents, but the area covered with tar (seams and perimeter) are surprisingly solid.

As insurance, I'm going to use Eternabond tape over the seams and Eternabond double-stick to secure the corner moldings. This would be a great weekend to do it, so, of course, the Eternabond is on back order and I won't get it until early next week. Plenty of other things to do...