Insulation, House Wrap, and Windows

I decided to spend a little more and get the best insulation I could. I chose closed cell spray foam by a company called Ecofoam.

Ecofoam truck backed up and ready for spraying

They did the job in less than a day. I wouldn't say it was an easy job though. The tight quarters of a tiny house, and covering and working around the loft joists made it difficult. But it turned out well and this insulation in a 4 inch wall will hold up to a cold Colorado winter.

Technically, it isn't necessary to cover the plywood with house wrap if it is insulated with sprayed-on closed-cell foam as the foam itself is a vapor barrier. But I covered it anyway. In fact I used a house wrap called Insultex which claims to have an R value of R6. I don't believe it though. The product is very good as  house wrap. It has two layers, the outer layer looking like the material used in a plastic tarp, with the reinforcing fibers running through it. The inner layer is thin foam, similar to what you might use to cushion the contents of a small package for shipment. Clearly, the product has insulation value, but I think it is minimal and considerably less than advertised. Even with that, it may be worth a bit more than standard house wrap.

Anderson windows were used.I got triple pane to resist the cold, and tempered glass to handle road trips. Once the windows were screwed into place, drip edges were added to the top, and the windows  were sealed to the outside using flexible flashing. I used a variety of window types, including awning, casement, double hung and picture, depending on the size and location.