Trailer skirting and insulation

Trailer insulation is a subject that is little understood. In particular the insulation under the trailer. The thing to remember about trailers or mobile homes is that there are a self-contained building. That is to say they roll out of the factory ready to be lived in. There are fully insulated and meet the demands of our Canadian winters. The older trailers manufactured in the 70’s were quite poorly insulated and the windows were drafty. It took a lot of energy to keep these trailers warm in the cold weather. The trailers in the 80’s were better with the introduction of 2×6 walls and R-20 in the attics. By the 90’s the windows were getting better and more efforts were put into shedding the old stereotype of trailers as trashy buildings.

One aspect of the trailer that has remained fairly steady throughout the years is the belly insulation. It has always been imperative that the floors were insulated where much of the waste and water supply lines were run. This was achieved by adding a layer of insulation under the floor and then placing the wood frame on a steel frame that would hold the insulation in place. If you look under a trailer you will see the black bag type material that holds the insulation in place.

Unfortunately about half of the trailers I climb under have a lot of damage to this liner material. When the liner is torn the insulation falls down and several bad things start take place. First of all the insulation falls down to the soil where it gets wet. Then mice use it as a ladder to gain access to the floor space. Finally the fallen insulation fails to keep the pipes and floor warm enough to prevent freezing. If you look under the trailer and notice rips or tears and exposed insulation you need to take action to stop the things I described above.

There are a few mistakes I commonly find under trailer. First mistake is trying to add heat under the trailer when it was never designed to be heated. Adding a heat duct from the furnace or running the dryer vent into the crawlspace simply creates a lot of frost and leads to mold. Trying to insulate the skirting and heating the crawlspace almost always leads to mold, remember the trailer was designed to have a cold crawlspace. I have even seen situations where people have put a mobile home on a foundation only to discover mold later on. The best solution to this whole situation is to keep the liner in good condition and make repairs to the insulation if any falls out of place.