Subfloor – Overview

It’s time to focus on the interior, and that starts with the subfloor.

The floor joists and beams should already be perfectly leveled and planar from previous work. Check them again with a long level and adjust accordingly in case the wood has warped.

Mineral wool is the ideal fibrous insulation to pair with spray foam due to its sound-deadening qualities. Rockwool was chosen because it was plentiful and slightly easier to work with than the alternative brands.

For a dead silent subfloor, nails must be avoided. They don’t have the holding power of a screw, and will squeak as they loosen.

Glue and screw the subfloor for a strong, durable solution. The glue is optional, but the screws are mandatory.

Ensure every screw is properly driven, not stripped or snapped. Pre-drill and countersink each screw location.

Expect to spend ~3 days doing the work outlined in this chapter.