I must confess: I’ve decided to use some pink foam insulation. I hate the stuff: it’s plastic, it’s a product of a polluting industry, it’s gross to work with, it’s non-biodegradable. And it has no redeeming ecological value. (Am I being harsh?)
It’s become clear that in my particular floor, at this particular time, and with my particular lack of willingness to experiment at this moment, it’s the “right choice”. Just over a week ago, April and I decided to go ahead and replace the entire earthen floor in the house, in hopes of continuing to alleviate the high humidity in Gobcobatron.
Earthen floor… with a vapor barrier
The original floor had no vapor barrier. At the time, I based that decision on what I read and what I had heard, but after two years it seems like perhaps the wrong choice for this climate. Our soil is extremely heavy, and very damp. I’ve no doubt that there is a lot of moisture underneath the house, and my guess is that some of it wicks up through the gravel into the earthen floor. Hence its stickiness at times of the year. And its penchant for developing mold if anything is sitting on it for too long, or if there is bad air flow over it (like under the bed, for example.)
Replacing the earthen floor
So we took out the floor last week. The idea is to lay down 6 mil polyethylene liner (another yuck) and somehow seal it to the foundation. Next we will craftily lay out the rigid foam insulation, which will be no small trick due to the lack of a regular floor shape. It’s 1.5″ thick, so it will provide at least some insulation. (It’s rated at R-7.5).
On top of that will go a 1.5″ base earthen floor layer, and then a 1/2″ finish floor, possibly completely tiled.
The rigid foam compromise
Anyway, the foam feels like a big compromise, since my goal has always been to use as few industrial products as possible. The natural alternatives are few and problematic for my situation: there’s light clay straw, but I don’t have the time to wait for a whole other layer to dry out before fall. Plus, I’m not confident about how well it would hold up over time. Perlite or vermiculite are other options, but both are really nasty to work with, expensive, and not that great on the eco scale, anyway.
In this case, I bowed to pink foam.
I do hope it serves us well. We shall see!