Exterior foam roof insulation

[gobygoby]

Originally Posted by Tango

What will be going over all this foam? Just paint?

The outermost layer is going to an elastomeric acrylic coating. It is designed to be on mobile home and RV roofs. It says it can reflect 91% of sunlight, expand and contract with temperature, and seal against moisture. I don't know how think it is, so I'm not sure how well it works against ambient temperature, but I've heard tons of good things about the product, including on this site. So it, along with the foam, should help quite a bit without cutting into the headroom.

[Tango]

So...basically, just a coat of paint? My concern was protecting the foam from both the sun (UV will wreck urethane) and everyday things like tree limbs & branches. Wouldn't take much at all to open a big hole with nothing rigid protecting the foam.

[gobygoby]

The paint will protect against UV, but you bring up a valid point about trees. I originally wasn't planning on driving the bus much, it was going to function more like a cabin.

I purchased the bus 2 weeks ago, but it was only this last Sunday that I had it moved from Decatur to Plano, and then from Plano to Willis Point. While in Plano, I did a quick paint job (white primer) which helped the bus look more like an RV, and less like an abandoned school bus.

I seller drove the first leg of the trip, and I had a full time bus driver do the second leg. She did a very thorough inspection before we left, tested all the lights, airbreaks, and tires. After the trip she said the bus drove really well. It only has 112K miles, and it ended up coming with more items than the original ad mentioned. The previous owner wanted it to be off grid and he filled the bus up with the remnants of his old project before dropping it off to us.

So my budget has increased a bit. I had set aside a little emergency maintenance money in case the bus needed a little help to make the drive, but the bus was in even better shape than I hoped. The previous owner topped off the gas tank, and there are a number of items I no longer have to buy.



So I am revisiting the notion of doing a roof raise.

[Tango]

If you are in need of serious insulation and headroom...then a roof raise is about the only workable option. I can see exterior insulation doing the job very well on a permanently fixed location, but not on anything that would ever go mobile. I've been on more than a few bus roofs and have yet to see one that didn't have some pretty serious scrapes...with the possible exception of one in Arizona.

And a roof raise is not as daunting as it sounds. Just read up on the related build threads here as there are a number of ways to go about it.

Best of luck on the build out.

[gobygoby]

I never thought the roof raise was daunting. After watching several videos and reading about them on this site, I am very comfortable with the idea.

My concern was time and cost. I need to live in this bus in 7 months, so the fewer projects, the better. Also, my bus already has the windows removed and sheet metal installed. So I would have to rip it out to raise the roof. Then I have the additional cost of creating new walls.

Because the bus is in better shape than I hoped, and because I found a better, closer, and free place to store it while I work on it, I am now able to expand the scope of the original project.