Sunday, February 08, 2009


Needing a little break from the barn, I decided to dig into insulating the basement of our house- a project I've been putting off for several years now. The first step was to insulate and air seal the rim joist. But first I had to tear out the existing material, which was tightly-packed fiberglass insulation covered with rockwool insulation boards covered with 1X8 wood boards, all the way around the perimeter of the basement ceiling. Those old farmers did an outstanding job of precisely fitting every piece and securely fastening the cover boards with what felt like barn spikes when trying to remove them...perhaps this was the best craftsmanship in the entire house! Every so often, I was 'gifted' with a mouse nest or ladybug colony just to keep it real. Definitely not the glory job, but important nonetheless. Once the history was removed, I insulated the empty rim joist spaces using leftover pieces of XPS from the barn project, then air sealed the edges using spray foam. Stopping all the air leakage alone made a dramatic difference in the basement temperature as well as the floor temp upstairs- if I had known how much cold air was sneaking in through the rim joist, I'd have tackled this a long time ago... Next, i cleared everything off the concrete foundation walls and put down a sill board spaced off the floor with strips of 2" EPS foam. A top plate was screwed to the ceiling joists above.
Next, sheets of 2" EPS foam were adhered to the wall with spray foam and a stud wall was built inside of it. (I used EPS here for its vapor permeance, to dry out any moisture that may come through the foundation and prevent any possibility of mold). I worked on a 4 ft. section at a time, and short cutoffs were screwed horizontally to the stud wall to temporarily hold the EPS in place while the spray foam cured. All the joints were sealed with additional spray foam, so that no air can get behind the EPS and form condensation. Finally, done for now. Eventually, we will add blown-in cellulose to the stud cavities then cover the works with drywall...but for now, I've got my workout room back (and it's a lot warmer down there!).

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