How Not to Build a Floor

September, 2017

The posts and the rafters are cut, the pies are made, everything is ready to raise the house…except the floor. Our working surface all summer has been a sheet of plywood over the substantial beams of the foundation. But since this is Wisconsin and we don’t want our feet to freeze to the floor in the winter, we’ll need some insulation underfoot.

It may seem odd to not have a traditional solid concrete foundation under our house, to build our house over open air, but let me remind you this is a hand-built house. For one thing, we couldn’t have gotten a cement truck up the hill to pour a foundation, even if we wanted it. And since we have a host of neighbors (skunks, ants, snakes, raccoons, mice, and all their friends and relations), who own our woods and are looking to move back in wherever it looks nice and cozy, we wanted make the space below our house less hospitable by leaving it open to airflow. Hence the need for insulation.

So we began by building a box on top of that original sheet of plywood, a box filled with joists.

Throughout this process we chose to slide the posts and beams of the house back and forth from end to end of the platform. It seems redundant to take them off the platform when they’ll need to be back up there in a few days to be raised. Above, we begin work on the east end of the platform, so the timbers are on the west end, and below, as we work toward the west to finish the joists, the timbers are slid all the way to the east end.

Once the joists were built, we filled their cavities with insulation. We’ve chosen perlite as our floor insulation, that white styrofoamy stuff you find in potting soil. It’s actually rock popcorn: a kind of rock which, when heated, expands like popcorn into an airy, insulative particle. The bonus of perlite is that it resists mold and isn’t attractive to mice or insects (here again, we’re looking to keep our neighbors away).

We looked for a super calm day for this job, since the stuff blows around like dandelion fluff. We poured it out of giant bags into the cavities between the joists, screed it flat, and screwed down sheets of plywood as we go.

And then the rain clouds started to gather…

Here is where we began to wonder if it was indeed wise to build an insulated, finished floor without a roof to keep it dry. The thought began to tickle just a little bit in the back of our minds, but we shrugged and kept going according to plan.

It’s not that the perlite melts or rots in the rain, but it seems to behave like thousands of tiny sponges. We’re not sure we want to live in such close proximity to a thousand tiny wet sponges.

We caulked the seams of the top layer of plywood and painted it with latex paint to help make it water resistant. (Here I died just a little. I had sworn I wouldn’t touch a single surface of this beautiful house with latex paint. Ah well, priorities, priorities…) We laid down a layer of tar-paper, tarped it with holey tarps, and crossed our fingers as the drops started to fall.

On a dry day we pulled off the tarps and got to work laying down the finished floor. This is beautiful stuff: 6″ oak rough-sawn boards J. picked from a pile at the local sawmill and had milled into 5″ wide tongue-and-groove planks. They’re still rough-cut on the top surface so we can sand and finish it later. We’re a little in love with the weathered surfaces, even though we know they’ll be sanded away.

And then it began to rain again.

We tarped the floor again and came back after the rain to find rust streaks in our flooring from the wet nails. J. went to the store and bought out the plastic sheeting. He laid it down in great strips and duct taped the seams. It began to rain nearly every night and every time we rolled back the sheets of plastic we found wet wood beneath.

Still, we learned some tricks to keep it on the dry side, and kept on laying down the wood.

Finally it was done (notice the tarps rolled back over the timbers). We left the corner by the stairs, which will be a tiled entryway. J. painted the floor with linseed oil to protect it from the rain, let that dry, and put the tarps over again. Because it would rain again that night.

Do I sound tense? That’s only because it feels like nature has been just the teeniest bit against us. Whenever J. has been available to work on the house it’s been either raining or a decidedly un-September-like 90 degrees, and the date of our house raising is fast approaching. We’ve been checking the forecast like it’s a newborn baby.

Also, J. is pacing the floor as I write this, rehearsing what needs to get done before the timbers go up and how exactly to do it. We’re both are such intuitive folks, approaching all our work (art, building, child-rearing, life decisions…) as if we’re feeling our way through a dark room, touching as we go, responding to what touches our fingertips and doing what seems best. This becomes hard when 30 of your dearest friends are looking at you, waiting for instructions as they lift the beams of your house over their heads.

At least that day it’s not supposed to rain.