Whats the best radiant barrier and foam insulation for walls, ceiling, and floor?

[Stevo]

I have a few questions about radiant barriers and foam insulation please. I'll be adhering the radiant barrier to the bare fiberglass walls and ceiling of a Toyota Sunrader motorhome followed by some kind of sheet foam insulation. Cost matters so I'm looking for the best bang for the buck.

1) Does anyone know what the best radiant barrier is? Enerflex is the cheapest but much thinner than the others. All are at Home Depot.

- Enerflex 4' x 12' x 1/16" for $14: http://tinyurl.com/an2ntyf

- Reflectix 4' x 25' x 5/16" for $42: http://tinyurl.com/d9u24mn

- UltraTouch 4' x 24' 3/8" for $60: http://tinyurl.com/aj9meq3

2) If I go with the much thicker UltraTouch that is 3/8", does that mean I could use thinner sheet foam insulation?

3) What kind of sheet foam insulation do you recommend? And would you use that same stuff on the floors too?

Thanks

Steve

[zero]

I have a few questions about radiant barriers and foam insulation please. I'll be adhering the radiant barrier to the bare fiberglass walls and ceiling of a Toyota Sunrader motorhome followed by some kind of sheet foam insulation. Cost matters so I'm looking for the best bang for the buck.

1) Does anyone know what the best radiant barrier is? Enerflex is the cheapest but much thinner than the others. All are at Home Depot.

- Enerflex 4' x 12' x 1/16" for $14: http://tinyurl.com/an2ntyf

- Reflectix 4' x 25' x 5/16" for $42: http://tinyurl.com/d9u24mn

- UltraTouch 4' x 24' 3/8" for $60: http://tinyurl.com/aj9meq3

2) If I go with the much thicker UltraTouch that is 3/8", does that mean I could use thinner sheet foam insulation?

3) What kind of sheet foam insulation do you recommend? And would you use that same stuff on the floors too?

Thanks

Steve

In regard to foam, closed-cell polyiso gives the most R factor per inch, but expanded polystyrene has the most compressive-resistance. As to "bang for buck", I can't say. Where I live polyiso is the best buy since I buy it wholesale at $5 per inch in 4 X 8 foot sheets. Much more at retail stores. Polyiso is usually not used on floors or foundation walls because of its low compressive strength.

[WME]

The reflectiveness is close to the same. Go to the MFG web site and dig around to find the actual R value. Check the $ per sq ft for both the foam and bubble foil.

2 layers of cheap foam and the cheap Enerflex may be your bang to the buck solution.

[MontanaChinook]

Yeah if you're doing other insulation, I'd say about any reflective foil, installed correctly, is going to be fine. The foil basically has no R value, from what I hear. If there is, it's maybe just under 1.

The foil is to reflect radiant heat from the sun. Then you leave an air gap, then you put whatever insulation you're using for R value. I did Radiant Barrier double bubble insulation. Not cheap, and I had to buy a roll, which it turns out is WAY too much for my little Chinook. I mean I expected leftover, but I didn't even use 1/4 of what came in a roll.

Then I'm just using really thin closed cell foam, in a roll. As thin as it comes, I think. My walls are thin, and any insulation is better than none, which is where I started with the walls. Personally I was more concerned with the hot sun baking everything inside, than I was with real insulation. I'm in the intermountain west. Sun is the biggest issue. I don't plan on winter camping, really, so my biggest concern was radiant heat, then I figured why not throw in some R value with foam, as well as a little sound insulation.

[Stevo]

Zach,

Is this the stuff you used? http://www.amazon.com/EcoFoil-Reflective-Insulation-Radiant-Barrier/dp/B003XFYIA2

Yeah if you're doing other insulation, I'd say about any reflective foil, installed correctly, is going to be fine. The foil basically has no R value, from what I hear. If there is, it's maybe just under 1.

The foil is to reflect radiant heat from the sun. Then you leave an air gap, then you put whatever insulation you're using for R value. I did Radiant Barrier double bubble insulation. Not cheap, and I had to buy a roll, which it turns out is WAY too much for my little Chinook. I mean I expected leftover, but I didn't even use 1/4 of what came in a roll.

Then I'm just using really thin closed cell foam, in a roll. As thin as it comes, I think. My walls are thin, and any insulation is better than none, which is where I started with the walls. Personally I was more concerned with the hot sun baking everything inside, than I was with real insulation. I'm in the intermountain west. Sun is the biggest issue. I don't plan on winter camping, really, so my biggest concern was radiant heat, then I figured why not throw in some R value with foam, as well as a little sound insulation.

[MontanaChinook]

Yes.

I won't be able to comment on how well it works until summer...and even then, I bought my Chinook last fall, so I won't have "previous summers" to compare it to. I guess if it sits out in the sun, and there's a 20 or so degree temp difference, I'll be able to say it works.

I'm using it and just some 1/8" closed cell polyethylene foam. I think I'll put the foam on the backside of the wall panelling when it goes up. That way I've got an air gap. The foil is right up against the fiberglass.