A subfloor sandwich - yum!

Our next project was putting down the subfloor over the concrete slab downstairs. We’ve talked to our neighbors who have the same type of house and they all say their floors are cold…we decided to avoid this by sealing and insulating the slab.  It took a lot of teamwork!

It was really cold, which made the tar too stiff to spread so we set the 5 gallon tar bucket right on the wood stove until it was a thin, soupy consistency and spreadable. We then poured the tar on the concrete and used a big 24" squeegee to spread a thin layer all over the concrete. While the tar was heating up we cut large sections of plastic sheeting which were later applied over the tar.

This is the floor in the kitchen/dining room. We laid the plastic over the tar, using our hands to push all the bubbles and bumps out until it was smooth.

After that we placed ¾” sheets of polystyrene foam insulation over the plastic/ tar vapor barrier. The foam acts as a temperature barrier from the cold concrete and actually makes the floor walk a little softer as well.

After all the foam was in place we completed our “subfloor sandwich” with 3/4" plywood on top.

We then used a powder actuated nail gun to secure the plywood and foam to the concrete slap. This is a nail gun that used a .22 caliber shell (same as a bullet - minus the slug) to blast a special nail through our subfloor and into the concrete. Pretty sweet, although after doing about 20, the novelty wore off!  Once we've picked out our flooring it will be installed on top of the subfloor. No more concrete….YAY!!!