Proper foam board material for creating Reflectix air gap?

[zen_stream]

When installing Reflectix I see that people are gluing strips of "foam board" to the interior of the outer skins to create the "air gap" which the Reflectix goes over the top of... but nobody on the forums has said what kind of "foam board" they are using. Ive been looking all over the forums. I can't find a single mention about a specific product.

I have a bunch of 1/2" R-tech. Would that be fine to use as a spacer material? Will it be fine to be right up against the inner part of the outer shell? It says its max operating temp is 160 degrees.

[zen_stream]

Here's a picture I found digging on the forums that illustrates what I'm talking about. This is what I'm trying to do under the reflectix to create an air gap. If someone can help me identity what type of foam product this is I'd be absolutely elated.

[5150mike]

https://youtu.be/0lOLT8_sSsc

Would this help you any

[zen_stream]

Im talking about insulating the walls not windows. Thanks for the link tho!

[Q-man13]

Anybody tried cork paint?

https://makeitright.ca/approved-products/vipeq/

[Q-man13]

Originally Posted by zen_stream

Here's a picture I found digging on the forums that illustrates what I'm talking about. This is what I'm trying to do under the reflectix to create an air gap. If someone can help me identity what type of foam product this is I'd be absolutely elated.

Looks like plain old styrofoam to me.

[doughpat]

I doubt the actual material matters much, a gap is a gap. I can't remember off the top of my head how big the gap is supposed to be, but I want to say it was closer to 1/8". Your 1/2" R-tech would probably do the job, but if it were me, I'd spend the time/money (not much of either) to get that gap as close to manufacturer's specs as possible. If the gap is 4x bigger than optimal, I could see substantial convection occuring in that cavity.

Its a bit of a messy and ugly idea, but what about a carefully applied thick bead of caulk? If you were somewhat careful I would imagine you could probably apply a grid/diamond/whatever pattern at a thickness of reasonable consistency. You could even apply the reflectix while its still wet and it would adhere (though might smash your gap a bit). Plus it would be a real bugger if you ever wanted to remove it. Just spitballing here.

What about foamboard sold in hobby shops? We used to use a foam called Depron when we built model airplanes...came in all kinds of thicknesses.

[Q-man13]

Originally Posted by Q-man13

Anybody tried cork paint?

https://makeitright.ca/approved-products/vipeq/

Quoting myself but on their FAQ under the other uses tab they say they have sprayed RV walls with it.

[JTChapmon]

I did a lot of research on this type of insulation when I insulated my metal garage door. Nearly everyone used insulation with one side reflective wrong. The best source is the individual manufacture's website. What you will find is the side towards the space TO BE insulated is the NON-reflective side. The other side should have a gap between the reflective surface and the outer skin/shell/covering. This creates an airgap and prevents conductive heat or cold from reaching the side wall.

[Bubba L]

As we did, running a piece of foamular, or any foam board, through the table saw is simple. Cut it any thickness you want for the dead air space.

[DavidsonOverlander]

Originally Posted by JTChapmon

This creates an airgap and prevents conductive heat or cold from reaching the side wall.

Isn't the reflective side supposed to face the side of the wall you most want to keep warm? So if you mostly want to keep your camper cool because you camp in hot places you'd face the reflective side out. If you mostly want to keep your camper warm you'd face it in. Or you could have a reflective side facing both directions.
Also, we're really just considering the movement of heat, not cold. Cold isn't really a thing, it's just a common way to describe the absence of heat.

[OTRA15]

FYI earlier related discussions are here:

https://www.airforums.com/forums/f44...er-218745.html

FYI
FWIW

[doughpat]

Originally Posted by Bubba L

As we did, running a piece of foamular, or any foam board, through the table saw is simple. Cut it any thickness you want for the dead air space.

Holy cow the MESS from that is not to be underestimated. I had to cut a ton of 3" thick foam for a foundation insulation and I was really embarassed at the mess it made. Blue foam drifts were gathering around the neighborhood : /. I dont even want to think about the microplastics I generated in that project....

If I were going to do it again, I'd rig up/buy a hot wire cutter.

[doughpat]

Originally Posted by Q-man13

Quoting myself but on their FAQ under the other uses tab they say they have sprayed RV walls with it.

Pretty interesting product, though I don't think it's appropriate for what OP is trying to accomplish. It doesn't seem like it would create an airgap. Not to mention that seems like it would be incredibly expensive when you factor in the labor needed to remove/mask off everything....pretty cool product though.

[JTChapmon]

https://www.youtube.com/watch?v=GFEwXPX2314

So, no matter which installation method you use, there has to be an airgap. found this little video. They talk about moisture barrier too. About 5 minutes in they start on radiant heat and the air gap.

[Monza]

Interesting video, makes sense but also makes it more confusing what to actually do in an Airstream.

Reflective on the inside of the outer shell, wool insulation and reflective on top of that makes a sealed reflective sandwich and then the interior walls. That's my thought process for today and insulation, subject to change next discussion.

[Unka Jack]

When I insulated mine, I made up a hot wire cutter based on some plans for model airplane construction. Pics on post #63 of my thread “ And so it begins......”