I removed the vinyl covered panel at the front of the overhead mattress on my C to check for water leaks/intrusion. There is fiberglass insulation at the very top where the front cap meets the roofline, and there were two pieces of fiberglass insulation at the bottom of the cap, laying on what I guess would be the "floor" of the cap. these are about 2 1/2" thick, and don't really cover that area. There is no insulation in the 20 or so inches between these two small pieces, and the insulation at the top where the cap meets the roof. I'm thinking about insulating the cap to help keep out the cold/heat. I was thinking about using soft foam such as used in upholstery padding, or older foam mattresses. Not memory foam, but something lighter than that. Is there any reason not to use the foam? I don't know about sweating, would that be an issue? I figure if I ever did get a leak, the fiberglass insulation would just get soaked and have to be replaced. The foam could be removed, cleaned and put back in. Anybody have any suggestions or advice?
Insulating front cap of a class C
- Thread starter kdbgoat
- Start date
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Gary RV_Wizard
Site Team
Why not get some fiberglass insulation batts or a small roll at Lowes or Depot and fill the space? I used the 6"x16" rolled insulation on mine and it fit into the openings rather nicely. The idea is to trap air rather than to fill it with solid material, so don't scrunch the material down too much.
Thank you for the reply Gary, but I really don't want to use fiberglass. I think I have also decided not to use foam either. Doing some reading, I think I have have settled on Roxul batting. And yes on not compressing insulation. With no air space, there's no insulating effect. I'm also considering adding reflectix along with the Roxul, but not sure which side of the Roxul to put it on. Should it go towards the outside surface, or towards the inside surface?
Gary RV_Wizard
Site Team
The US Dept of Energy says reflective barriers should face an air space. I've never been clear why that is, but they seem positiveabout it.
https://energy.gov/energysaver/radiant-barriers
https://energy.gov/energysaver/radiant-barriers
Well, I got the insulation done night before last. I just used the Roxul. It came out pretty good I think. The removable panel only attaches with 2 screws, one at each end. That leaves a gap in a lot of places. Deb took some bulb type weatherstripping and put around the edges to seal it better. That came out pretty good as well.
I decided against the reflective barrier for a couple of reasons. One it should be mounted on the warm side. The warm side will be dictated by the weather. Two, it needs an air space and there just isn't enough room for an air space and the insulation. Three, if I did install it to the cap with an air space, how much heat would build up between the barrier and the front cap when the sun is beating down on it? I feel it would be detrimental to the cap with a lot of heat buildup between the two.
I decided against the reflective barrier for a couple of reasons. One it should be mounted on the warm side. The warm side will be dictated by the weather. Two, it needs an air space and there just isn't enough room for an air space and the insulation. Three, if I did install it to the cap with an air space, how much heat would build up between the barrier and the front cap when the sun is beating down on it? I feel it would be detrimental to the cap with a lot of heat buildup between the two.
