Spray Foam Undercoating / Insulation

For -35? I would cover it with an insulated tarp and put a wood stove in it. :)

Steakman wrote:
Well, I'm looking to go about 3-4 inches of this product...? and for the winters up here (-35+), have a skirt.

First, no way would I try to live in an RV in -35 deg winters.

Ken

FYI some foam is known to attract carpenter ants to nest in, I had it happen to a metal building, and had to scrape all the foam off to get rid on them.

Hi,

I don't skirt as I'm on the road too much.

I have looked into spray foam and have decided against it. I feel that high pressure spraying of slush from the road might well penetrate and then never dry out.

If planning on using lots of electric heat, then upgrade the "stab" connectors with real screw terminal outlets.

I solved the cold floor problem with electric heated carpets.

The safest heaters may be the oil filled units. The surface temperature doesn't get hot enough to scorch materials.

My waste tanks and valves are enclosed. Some one at the factory failed to install a heat duct. I added a 600 watt heater on a mechanical thermostat.

I replaced the cold air return grill with dual window fans. They are on a mechanical thermostat and keep the fresh water lines from freezing.

The peak electrical load is about 7000 watts. I added two auxiliary shore power cords which gives me OEM 30 amp, 20 amp, and 15 amp inputs. I power those from a 50 amp pedestal where I use a break out box to give me a 30 amp on one leg and dual 20 amp outlets on the other.

Remember that, for continuous duty, a 30 amp circuit should not be driven past 24 amps, 15 to 12 amps and 20 to 16 amps.

I am able to successfully heat 100% electrically, provided that there are adequate shore power outlets.

I have had occasion to use an autoformer to boost voltage during the winter months.

There is a great thread on winter camping in the full time forum.

I've used my RV wet at -37 c.

The only foam that is close cell is XPS foam.

Spray foam will work but even the best application is only 90% close cell...which means that it can absorb 10% water so it needs to be covered.

A buddy of mine has spayed it for year. I would tell him that 2lb foam shouldn't spay a roof.....move ahead 10 years...they changed the BC building code so only 1/2lb foam can be sprayed in a roof which allows water to pass through.

How about skirting made with snow, hay, fabric or boards.

It will do a great job but it will be a pain to do any repairs afterword.
BTW, you want to make sure you use closed cell foam which is water proof.

Just remember that to be effective, insulation must be continuous and that means if you are insulating the underbelly that the sides of the I-beams must be covered as well. Then if you only add insulation to the underbelly between the I-beams, then a full 25% of the floor area (I-beam to wall) receives no benefit. And that is not counting the slide out floors which are the least insulated. Finally, there are the slide out mechanisms that can't be sealed with spray foam.

Skirting using rigid foam board may be more effective if the unit is stationary.

We have a lot in common. When I was a tie in welder, then tie in foreman , then welding boss ffor OJ we laid Alliance PL around Whitecourt Ab. Jan- Apr. 2000. We camped by the Athabasca bridge, never froze. Batched filled and dumped from the camp water. We had a H/R 32' TT , skirted with vinyl
First I heat traced the water lines with SS 5 w/ ' cable, glued old water ned heaters to the holding tanks, added 1 1/2 pvc 'brick mould' to the frame to allow additional 1 1/2 HD foam insulation. Then put coroplast underbelly on
A neighbor in the camp did the spray foam over his heat traced water systems. It didnt work in the -40c . May have been his set up.
Remember, you must vent all your shower and cooking moisture, use a dehumidifier.
Search for bobs your uncle, pianotuna. These guys from Calgary and On. have also done it.

I'm just wondering if spray foam insulation will make it harder or almost impossible to access stuff might need repairing....plumbing, electrical, etc.

I'd use bat insulation and coroplast.

Well, I'm looking to go about 3-4 inches of this product...? and for the winters up here (-35+), have a skirt.