View Full Version : Keeping warm in an aluminum cap...

02-09-2012, 01:41 AM
Hi all,

Just got myself a used LEER DCC wedge cap for my 07 Tacoma. I plan on a full sleeping platform build and will be using it just as much if not more in the winter months for skiing.

Any ideas for insulation?

I'd imagine the aluminum won't fair to well in colder temperatures and it would be nice to keep in some of the warmth.

The interior is similar to this:


Thanks for the input

02-09-2012, 01:50 AM
You're facing a similar challenge as me in my Toy Box.


My ceiling is the same as yours. One piece of advice that I was given was to get some cans of expanding spray foam to insulate the hollow ribs. If not, they'll conduct heat away even if they're covered with insulation.

the suggestion was to drill access holes in the tubing, attach a longer nozzle to the spray insulation, slip the nozzle in then retract it as the trigger is pulled so that the aluminum tubing fills.

My plan is to use foil covered insulation so that I get the highest R-value. There are plenty of adhesives to glue the foam to the sheeting.

02-09-2012, 02:48 AM
On my last aluminum cap I used a layer of refectix covered by a layer of thick fuzzy headliner like used in RVs. I bonded the two together using 3M spray adhesive. To hold them on the roof I used 3/8" wooden dowels. I sized the insulation panels to fit between the hoops. I drilled holes in the support hoops and just popped the sticks into place every foot or so. Nothing was glued, so removing it was easy if you needed to route wires etc. It never sagged over 20 years of use. I spent a few nights in Wyoming in that cap when it was -7 outside. I had a small catalytic heater and it kept it quite tolerable. You do need to cover the support hoops with something. Even insulating the inside is not enough. The aluminum will condense water and drip. Something like plasticoat can be sprayed on those ribs before you lay up the liner. I also made snap on insulated window covers that drastically reduced heat loss through the glass. I spent many winter nights in that rig!

Come to think of it, that cheap stuff they sell for automotive carpet would work well as the top layer.

02-09-2012, 04:58 AM
When I worked at a camper shell place we used a felt liner to put on the skins of the shells for insulation. If you want to do it on the cheap, go to your local carpet store and get some carpet foam out of the dumpster, glue that on the exposed skin then glue a carpet remnant over the top of it all. The reflective insulation is a good idea, but runs around $50 per roll and the condensation will be dripping off of that while you sleep.


02-09-2012, 11:40 AM
If there's condensation then there isn't enough ventilation. It isn't an insulation issue. This is physics...cold air can't hold as much water as warm air.

Unless you have a high output heater to actually keep that shell warm you're going to either be cold or have condensation. Ceiling insulation by itself won';t do you much good because of all the window surface.

02-09-2012, 12:31 PM
This would be my starting point:
Definitely look into close cell spray foam. I believe this solves any condensation issue and gets into every nook and cranny. There is low and high expansion rates. High expansion cans can be used for filling the ribs. This stuff expands 30 to 40 times it's liquid state! I'd look into low expansion for the metal surface. The homework part is whether you can do-it-yourself as you'll need a fan type applicator. If you can do it yourself, after it sets up, you could probably trim it even with the ribs with a wallpaper trim guide. This is essentially a 24" putty knife. You'll probably need to file a bit of an edge to the trim guide so it cuts clean.
Look in the home stores. At Home Depot, you're more likely to find someone knowledgeable to help. Lowe's tends to forgo the knowledgeable employees for a better product selection, on average.

Spray foam sticks well but is removable. It comes off clean in big chunks.

02-09-2012, 01:48 PM
If there's condensation then there isn't enough ventilation. It isn't an insulation issue. This is physics...cold air can't hold as much water as warm air.

Unless you have a high output heater to actually keep that shell warm you're going to either be cold or have condensation. Ceiling insulation by itself won';t do you much good because of all the window surface.

This isn't true. Temperature of the surface determines condensation. You can set an aluminum cup filled with ice water out on the patio and see how fast condensation forms. The amount of ventilation can affect the moisture in the air, but in a closed space like a camper, you will always have high humidity. Most of it comes just from breathing. You can't ventilate the problem away. Any uninsulated exposed aluminum will condense water. It all has to be covered with a vapor barrier and insulation of some kind.

02-09-2012, 02:11 PM
I had an aluminum shell when I was stationed in WA and it was pretty miserable. During the winter months water would condense on the inside of it and drip down into the bed. It even ruined some of my tools. Eventually I sold that topper and replaced it with one that was made of polycarbonate plastic (the Brahma type of shell.) That one at least had a thin felt liner in it.

I think if you can get something to coat the inside of the shell you will be much happier, especially if you intend to sleep back there.

02-09-2012, 09:30 PM
Not cheap, but you could have it sprayed with a bedliner product.

Desert Dan
02-10-2012, 12:15 AM
Wait till a big rain or hail storm LOL
Bring some ear plugs.

Maybe you could find a roofing company that sprays the foam on roof tops and get it done at a job site?
I'm sure it wouldn't cost much as they probably had the empty the spray gun at the end of the day:)

02-10-2012, 09:31 AM
[QUOTE=Desert Dan;1045754]Wait till a big rain or hail storm LOL
Bring some ear plugs.


SC T100
02-10-2012, 03:13 PM
Dynamat or similar could be applied...then some headliner material. That would help with both the noise and the condensation issue.

02-10-2012, 03:53 PM
I think the carpet pad idea is fabulous. Just be careful using an open cell foam like that- it needs to breathe. If you cover it in something non-porous, the whole thing will smeel like the bilge of a boat. If you're handy, you can cover 2 layers of it in some fabric to put over the windows. Ventilation is key. Better to be in a warm sleeping bag surrounded by cold, dry air, than in a lighter, soggy bag, with everything wet in the morning. I have one of the Cabelas Trekker bags for that kind of thing- it was cheap and about useless ABOVE 30F. Before you crawl out of bed, just flip on a little heater, and you'll be toasty in no time.

Desert Dan
02-10-2012, 03:58 PM
Caravan Campers in Reno, NV uses a product called Zolatone to coat the isnside of their metal camper shells.

It is probably for sound/vibration dampening rather than insulation ?

ZOLATONE 20 Series is the perfect OEM and refinish product because of its great looks, camouflaging ability, ease of application, and substrate versatility. Zolatone 20 Series is ideally suited for applications on:
病luminum and fiberglas boat interiors
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02-10-2012, 04:00 PM
If you plan on sleeping back there, especially in cold or wet environments (sounds like both) then IMO your best course of action would be:

Sell the aluminum cap and get a fiberglass topper with a liner. Warmer, drier and better overall. Aluminum caps are OK for dry conditions, or if you just want to keep your stuff secure, but there is a reason most people who sleep in the back of a truck use a fiberglass topper.

You might be able to find a used topper on CL. I found two of them when I owned my Taco, and the most I ever paid for one was $300.

02-11-2012, 03:24 AM
Check out my thread. I sold my fiberglass shell and picked up a contractor aluminum shell. To say the least, I did a few modifications including insulation...



02-11-2012, 03:32 AM
It was also lined with a trunk carpet material.


02-11-2012, 05:21 PM
I cut pieces of foam board and glued them in between the ribs on my former aluminum shell. I think I used some caulk or silicone to seal the gaps around them. It was pretty comfy to sleep under. I never saw any condensation.

02-15-2012, 06:36 PM
I glued and taped in Styrofoam board super warm, no condensation, and quiet. For the curved edges I used 4 layers of aluminum foil insulation works great, easy, light, and cheep to install.

02-15-2012, 09:43 PM
If you use adhesive on foam board, make sure it lists "for foamboard". I'm not 100% sure but I believe some that are petroleum based are not suitable.
Heavy Duty Liquid Nails is suitable.