As I have mentioned in earlier threads, I want to do more cold-weather camping next fall and winter. But I am having a heck of a time figuring out how to heat an enclosed underbelly when we don’t have hookups (which is most of the time) – my furnace won’t do the job (no place for ducts), and it is tricky to use my water heater as a heat source, at least until my electrical skills are greatly improved. And heat tape is out of the question – it would draw too much current when we are boondocking. (So would the furnace, really.)I am pretty sure I can beef up the insulation with Styrofoam boards, and cover the whole underbelly with coroplast. So that is my question – without a heat source, is that a project worth doing? I do understand that inanimate objects don’t suffer from “wind chill,” so cutting down on the wind under the trailer by enclosing it won’t accomplish much. But if this project will even slightly cut down on the risk of freezing my tanks and my lines, that would be a big plus.Your thoughts and advice are always appreciated!

I've owned trailers with and without enclosed underbellies and never noticed any difference at all between the two. I'd suspect that you achieve better heat retention in cold weather by skirting the trailer with something like Reflectix that would prevent cold air from blowing under the trailer.

Dan,Yes, it will help.I would suggest something other than "Styrofoam" though as, if/when water gets up there, Styrofoam will tend to absorb it. I used about 2.5 inches of spun fiberglass insulation (easier to fit around wires and plumbing) held up with 2" thick foam made to go below grade. Long screws with fender washers hold up the foam and all joints are taped. Reflectix type insulation under the foam and, finally, the corplast. As recommended by another forum member, I put drains in the Reflectix/Corplast so, if/when water gets in there (it will), there is a way to drain it out. Radiant heater above the fresh water tank keeps the floor warm and, via conduction, the tank seems to stay "warm enough". Of course, your layout may not allow for this.Might want to wrap any plumbing down there with heat tape and foam pipe insulation so, if needed, you have a way of thawing it out.Hope this helps.

From a wind standpoint alone, I say yes, small as it may be.

Styrofoam absorbs water? That's news to me. The stuff they sell as insulation board seems to be somewhat denser that plain styrofoam tho. But neither absorbs water so far as I have heard. Spun Fiberglass dies when it is exposed to water tho so I wonder if your advise is good. From the Lowe's website, the info sheet on insulation board:------------------------------------------------------------Specifically developed for wall sheathing, basement insulation, siding underlayment and foundation insulationExcellent insulating properties and moisture resistance

A dense, sprayed-on urethane foam insulation should not be able to ansorb water. It sticks well and is seamless. And it acts as a vapor barrier, which adds to the insulating factor, so less thickness is needed than other forms of insulation; this has been proven in such applications as potato storage in ID.

Worthwhile to insulate/enclose underbelly without heating?

25 Replies

rexlion
Explorer
Apr 21, 2018
A dense, sprayed-on urethane foam insulation should not be able to ansorb water. It sticks well and is seamless. And it acts as a vapor barrier, which adds to the insulating factor, so less thickness is needed than other forms of insulation; this has been proven in such applications as potato storage in ID.
agesilaus
Explorer III
Apr 21, 2018
Styrofoam absorbs water? That's news to me. The stuff they sell as insulation board seems to be somewhat denser that plain styrofoam tho. But neither absorbs water so far as I have heard. Spun Fiberglass dies when it is exposed to water tho so I wonder if your advise is good. From the Lowe's website, the info sheet on insulation board:
------------------------------------------------------------
Specifically developed for wall sheathing, basement insulation, siding underlayment and foundation insulation

Excellent insulating properties and moisture resistance
Lwiddis
Explorer II
Apr 21, 2018
From a wind standpoint alone, I say yes, small as it may be.
SteveAE
Explorer
Apr 21, 2018
Dan,

Yes, it will help.

I would suggest something other than "Styrofoam" though as, if/when water gets up there, Styrofoam will tend to absorb it. I used about 2.5 inches of spun fiberglass insulation (easier to fit around wires and plumbing) held up with 2" thick foam made to go below grade. Long screws with fender washers hold up the foam and all joints are taped. Reflectix type insulation under the foam and, finally, the corplast. As recommended by another forum member, I put drains in the Reflectix/Corplast so, if/when water gets in there (it will), there is a way to drain it out. Radiant heater above the fresh water tank keeps the floor warm and, via conduction, the tank seems to stay "warm enough". Of course, your layout may not allow for this.

Might want to wrap any plumbing down there with heat tape and foam pipe insulation so, if needed, you have a way of thawing it out.

Hope this helps.
SoundGuy
Explorer
Apr 21, 2018
I've owned trailers with and without enclosed underbellies and never noticed any difference at all between the two. I'd suspect that you achieve better heat retention in cold weather by skirting the trailer with something like Reflectix that would prevent cold air from blowing under the trailer.

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Worthwhile to insulate/enclose underbelly without heating?

25 Replies

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