My bride kept complaining about seeing daylight from the cargo area how porous the trailer was regarding outside air. We decided to insulate using a closed cell spray foam called green foam. Measuring one inch thick the calculation indicated 200 square feet at one inch thick for an R factor of 7. Did not happen. I wound up buying two kits or 404 square feet. It is not pretty, but the trailer is totally insulated now underneath and in the cargo area along with the storage area behind the slide out. Prior to spraying, I insulated all the water lines I could get to with the tubular pipe closed cell insulation from Home Depot. This took several hours and a lot of tape to get everything covered. Some areas were very tight and I had to use large internal diameter insulation covering both hot and cold due to lack of space. I also covered all water lines and propane lines with hard board type insulation so I could easily remove the foam if a leak or repairs will be needed. If a leak occurs it will take some time to dig out but I feel the insulation will be worth the time. I called Sunny Island RV and discussed my plan with them and their local expert on RVs said go for it. They use bat insulation covered with a plastic cardboard type material. Steve from SIRV warned me that I might have to dig out if I have a water problem etc. but it is not that difficult. Using a vibrating cutoff tool (dremel etc.) removes the insulation easily.
Sorry, no pics as I could not post prior to today and I returned my trailer to storage. Quite honestly it is not pretty but I guarantee you the bottom of the trailer and cargo areas are covered! I look forward to experiencing some cold weather to see how much improvement I have made. Please note one cannot see my efforts unless you are on your back looking up under the trailer or happen to be around when the cargo door is open.
For the record, average thickness is three inches underneath the trailer, I did not cover the bottom of the three tanks as these flex a lot and did not feel this was needed. I may change my mind after some actual experience.
MonteD
Very interesting. I've wondered about doing that and appreciate how much work it must have been. How do you think it will hold up to the flexing of the trailer and to water? Does it dry flexible and waterproof? Did you have to cover electrical connections to protect them from the goop? I'm looking forward to further reports (next spring?)
I spent a lot of time researching the foam thing. Just type in Green spray foam or foam it green and check them out. It is pretty simple as far as spraying the foam. Problem is when spraying you are on your back with about 20 inches of room to move around.
The foam dries very hard and rigid and is said to add structure. This is why I did not spray the tanks due to flexing.
Yes is is waterproof due to it being closed cell foam; again you can read about it online. It takes a cutting tool to remove excess spray foam but again very easy. I was told by the company that it sticks very well to virtually anything.
I covered all water lines with the tubular closed cell foam from HD and propane, and some electrical lines depending on where they were. The electrical lines are in a plastic tube so I was not too worried about these.
I think the best part of the insulation will be in the cargo and slide out areas. These were somewhat difficult due to the tight areas but they are certainly better than before.
I am sure we will be using the trailer in December (we live in GA) and will give more info as to the value of the process. When spraying the bottom of the trailer, the aluminum has the one inch channels and I can already tell the foam will not be dropping out of those areas or anywhere for that matter. Again I sprayed the first tank several weeks ago and ran out about half way through the process, ordered a second kit to finish the job. The foam from two weeks iseks ago was solid as a rock after about 20 miles of travel. I guess only time will tell but it is certainly easier than trying to install batt/sheet insulation and making sure it stays put. I really do not think this stuff is going anywhere even in the rain.
I now think the bottom of the trailer is better insulated than the walls or roof so it will still get cold or hot; but better than what is was.
[p]Glad to hear this stuff gets so hard. I intend to use it under the trailer beneath the shower pan, the refer and the dinette boxes. A friend uses this from time to time in construction and I'll need to nuzzle in on some as a full kit is too much for me to use.[/p][p]
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I did check out the stuff on- line and found they make a small kit for patches that covers 12 square feet. Might be good for specific areas under the trailer.