External Roof insulation?

[n4matix]

Hello all,
New to this forum, just picked up a 1988 56 passenger family conversion project.....want to insulate since much travel will be in the summer and A/C is critical....but my family is TALL (I am 6'6") so I already have to stoop. Has anyone attempted some sort of foam and wood combination on the roof, outside, in order to leave inside ceiling as is? What about insulating the floor from the underside without encouraging rust/moisture? The family really wants the conversion to look like an old-style wood panel truck when we're done, so wood on the roof would go well. Of course there is the deck idea, I read in the forum folks who have a roof deck comment it protects the ceiling from heat....anyone want to comment on the long-term stability and performance of their roof deck and whether or not it helps keep their ride cool in the summer? Maybe some insulation hiding under the deck might be a viable option as well? Ah, so many questions....just don't want to do this twice, not competent enough to raise the roof, and trying to keep the costs to a minimum if possible.

Thanks in advance for any and all thoughts/ideas!

[GoneCamping]

I briefly considered the idea of glueing some Reflectix on the roof, that would eliminate the hot roof even in direct sunlight. Unfortunately I couldn't figure out a way to make the stuff stay put under high wind conditions as would be experienced while rolling down the interstate...

BTW, I'd still like to do that, just haven't figured it out yet!!

[coyotesight]

Super therm or another insulating paint, inside and out, this may give you the insulation you desire without the loss in headroom.

[Xtevan]

You can use the Kool coat type elastomer type paint with ceramic beads. Or you buy your own 3m glass beads for cheap and add to rustoleum type paint from here:

http://uscomposites.com/fillers.html

I could not find the original post to give credit. I did one coat of rustoleum gloss white with the beads added to it- it looks pretty flat because I tried to apply it with a low nap roller instead of a foam roller. I have meant to do another coat but I've been way to busy. I went with the rustoleum blend because I plan to add a deck like on Lucinda in the gallery.

Anyway over the previous three weekends I camped in the bus at a regional burning man and two weekends of a music festival. While I don't have a baseline for the orange roof I was pleasantly surprised, I typically slept till 11 or so and was awakened by people rather than the heat. My tent camping friends were cooked out of their tents by 9:30. I wouldn't go into the generator saga here.

[Elliot Naess]

Hello n4matrix, and welcome!

The roof deck as a heat shielding "second roof" is a well established concept. Some of the most energy efficient homes being developed these days have "two roofs" -- a "real" roof, and a shade structure a foot or two higher. You also see this at the low end of older housing all over the country -- the pole shed that some people build over old mobile homes. It works!

Now, you ask if anyone has used foam insulation on the outside of a roof. Yes. NASA. Chunks of such foam has often damaged the famous "heat shield tiles" on the space shuttles. I think I read that they spray the foam onto the outside of the giant external fuel tank, and sometimes chunks of it peel off. Of course, this happens at several hundred miles per hour, so I would venture a guess that it is worth trying on a 60 MPH bus.

That said, since you want a wood exterior, I'm thinking that the combination of spray foam and your wood structure that terminates in a roof deck....Well, I like it a lot -- provided you don't build it too awfully heavy. The main issue would be keeping water out, while allowing air circulation. That prospect I don't like so much. The only way I would try that, would be to deliberately allow rain water to run down the side of the bus behind the wood siding -- which I think is perfectly realistic and doable. A school bus is eight feet wide, so you can add an inch of foam (more on top), an inch air space and an inch of wood, and still be legal at 8' 6" wide.

THAT said, it is my opinion that you need to rewind this tape and raise your roof first. You say you are not competent to raise the roof, and I do appreciate a man who understands his limits. A valuable trait. But raising a roof is not all that difficult. Sure, it's a lot of work, but the difficulty is mostly in the planning. So you might want to read more about roof raising, and then ask yourself for a second opinion. Believe me, at 6' 6", you will not be a happy camper for very long with a 6' 2" ceiling.

Oh... did you mean solid foam sheets? Raise the roof and slap in all you want of those! I wouldn't want those out in the wind.

That any helpful?

Again, welcome to the forum!

[n4matix]

Well, my company sent me away to Baltimore for a month for training......but wanted to post again on this topic to say that I went with mobile home roofing type paint because it was cost effective and because many others on this site have spoken highly of it. I have to admit I was initially skeptical, but it actually helped with the temperature control and I think it also helped a bit with noise. Anywho, I also installed a 15000 BTU window unit in the back and run it off a generator while camped -- managed to maintain 70 degrees inside during 100+ degree oklahoma weather, so I am not complaining about the height issue.... Having said that however, I showed the wife the post and the pics on raising the roof and we are going to have a go at it next spring assuming the budget will allow; however, it may not be on this bus as we have already had three offers to buy it even though it isn't for sale. Seems that bus-turned-to-RV speaks intimately to hunters, and deer season is approaching.....