The Great Insulation Debate

I went through quite a journey this morning thinking about how to insulate our tiny house. For the last year or so, I've been planning to use either recycled denim or wool insulation. They are natural, non-toxic products that are safe to install. But, I've also been talking with builders I know to ask their opinions. Specifically I was asking about how to insulate the floor in a way that minimizes the height inches that could otherwise be used as valuable head space. My dad has been brainstorming for me and we considered laying blue board on the deck of the trailer and laying the floor right on top of it. This would take about 2 inches. Yes! Saved 2"! Then we thought about putting the blue board under the deck. Saves another 2". Then he suggested that it might be better to use spray polyurethane foam (SPF) under the deck as it would completely seal the floor of the deck.

 Hmm... I'll have to think about that. Yesterday I asked my uncle his opinion as he is a building contractor. He suggested that we use the foam not only in the floor but in the walls and ceiling as well. It would provide an R-value (this is the unit of measurement for how well an insulation prevents temperature transfer) equal to a standard house with just an inch an a half of foam. It would also contribute greatly to the stability of the structure because when it hardens it adheres to the surfaces it's in contact with and would basically make the floor, walls, and ceiling one continuous solid mass. This seemed highly desirable to me. However, I'm also highly concerned with toxicity in the home.

So this morning I went on a google quest to find out more about insulation. I found this website developed by the EPA to help people use SPF safely http://www.spraypolyurethane.org/. Then I discovered that Ecovative is developing an insultaion made out of mushrooms!!! http://www.treehugger.com/green-architecture/tiny-house-mostly-made-mushrooms.html, http://www.ecovativedesign.com/products-and-applications/insulation/. I want it. Unfortunately it is not available yet. Bah! Then I discovered this article which put me pretty solidly back on team denim. http://www.treehugger.com/green-architecture/whats-the-greenest-insulation.html . Apart from the dangers associated with installing the SPF which include inducing extreme chemical sensitivity, this quote reminded me of a lot of other things that are important to me:

...there are many legitimate arguments against the use of a petrochemical, high-embodied energy, non-renewable, non-recyclable, non-permeable, difficult to remove, problematic for renovation, and expensive insulating material.

I guess we'll just have to use a lot of good screws to ensure the structure is solid.