Red Barn Renovation: The Magic of Spray Foam Insulation

Last Friday night, I found myself ranting about building insulation to a disinterested friend. “But you don’t understand, dude,” I insisted, “this new spray foam stuff is revolutionary!” Thankfully, I knew you guys would enjoy these pictures — you’re almost as nerdy about home improvement as I am!

Back in the forties and fifties, our barn was a fully operational chicken shack, designed to house hens, not humans. When we first moved here, light and air streamed through the plywood walls and rotten rafters. In the summer, it was sweltering — in the winter, you could see your breath. (Under such miserable conditions, I’m surprised these cooped up birds didn’t stage a coup!) As I intend on working in the barn year round, properly insulating was a top priority. But which type were we to use?

With my workshop soon to be stocked with expensive steel tools and cast iron machinery, it was critical that we kept out moisture and it’s close cousin, rust. To do this, we needed to better seal our “building envelope,” the term specialists use to describe the layers of materials that separate indoors from outdoors. Downstairs, the porous cinder block walls were highly susceptible to moisture infiltration — upstairs, we needed to prevent air from escaping. Since fiberglass batts perform poorly under damp conditions, we opted for spray foam insulation.

About as awesome as insulation gets, spray foam is a two-part solution that mixes together when sprayed upon a surface. It comes in two different varieties: “closed-cell,” a polyurethane-based mixture and “open-cell,” made from isocyanurate. In terms of R-value, a measurement of resistance to heat flow, closed-cell is a superior insulation. Its denser composition provides an R-value of nearly 7.0 per inch, whereas open-cell offers 3.5 per inch. While that rating may be comparable to fiberglass, spray foam fills gaps and forms airtight seals where fiberglass simply cannot. Also, it expands like a microwaved marshmallow (to 100x its initial volume!), which is pretty much the silliest thing ever.

But as you can see from the nuclear fallout suits and heavy-duty respirators, during its application, this stuff is pretty bad for your brain. Fortunately, once the fumes dissipate, it is completely non-toxic. Of course, I had to snap a few photos while they were spraying — I tried holding my breath, but the damage was dumb…I mean done!

Images: Johnny Williams

Late last year, I kicked off a series of posts in which I’ll document the transformation of an old barn into my future workshop.