Tiny House: Insulation

Tiny House: Insulation

May 10, 2017 Categories Tiny House

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Whoo! Today the installers finished putting in the closed-cell foam insulation and it looks BADASS! My tiny house actually feels more like a house than a shed! I’m pee-my-pants excited to finally start working on the inside of the house.

This is hopefully the only thing about my house that I’ll have to hire someone to install. Believe me, if I can do something myself instead of paying someone else to do it, I will (unless it’s mudding drywall). Closed-cell foam is not something to mess around with. I’ve heard stories and seen videos of people who can’t even live in their house because of a bad installation. There’s two chemicals that are combined during the install and if that mixture isn’t done correctly, not only will you have crappy results, but it can create a toxic off-gassing that makes the home unlivable. I definitely don’t have the knowledge or equipment to even attempt installing spray foam myself. I’m not taking that risk, nor would I recommend anyone else. Hire a professional and get it done right.

I’ll flat-out say, closed-cell foam insulation is EXPENSIVE. If you’ve looked into different types of insulation before, you probably already knew that. It is by far the most costly part of my build, other than the trailer itself. However, that price tag comes with several benefits:

  • Very high R-value.

    The specific brand/type of closed-cell foam I got installed has an R-value of 7 per inch of foam thickness. I had three inches sprayed in the walls and five inches in the floor and ceiling. That’s a total R-value of 21 for the walls and 35 for the floor and ceiling. Up here in Wisconsin, that’s pretty darn good!

  • Air-tight.

    As the foam is sprayed, it instantly expands and fills every tiny nook and cranny it can get into. You don’t have to worry about drafts or air leaks bringing your R-value down.

  • Rigidity.

    Unlike open-cell foam (the stuff you can buy in spray cans), closed-cell foam is hard and very rigid. Once it’s sprayed in, it helps to strengthen the structure itself.

  • Energy efficient.

    Since spray foam can fill every little crevice and has such a high R-value, it makes it an incredibly energy efficient insulation. Being that my house is gonna be heated by a tiny wood stove and will probably only be lit when I’m at home and awake (roughly five hours a day), I need as much heat as possible to stay inside the house during Wisconsin winters.

  • Built-in moisture barrier.

    Unlike other types of insulation, spray foam doesn’t allow water to pass through it. This means it is its own moisture barrier. To top that off, it also helps to deter mold.

For most people, the benefits probably don’t outweigh the cost. Luckily, there are a ton of insulation options out there and it’s all about picking what will work best for you.

I think the company I went with, FoamTech Insulation, did an amazing job. I don’t consider myself easily impressed, but they greatly exceeded my expectations. Even spraying the foam in the cramped, “crawl space” area under the trailer, they still took the time to make sure it was a very clean install. Everything is smooth and level. They even took the time to wrap my axles to avoid getting any foam splatter on them – I wouldn’t have done that if I installed it myself!



One thought on “Tiny House: Insulation”

Helen Opie · May 11, 2017

That IS impressive work! Insulation pays for itself, and keeps you snug while doing so. I read of a Canadian (in mild BC) who used foam blocks as his walls, with small (strapping?) net to connect the window frame holes to the walls. This is similar and perhaps better, if pricier. But you only need to do it once.

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