New Basement Finishing Plans

Q: How soon can I safely finish the basement in a new home? Is three months long enough for the concrete to dry out? How can I deal with the four feet of insulation hanging down from the top of the basement walls? There’s no stud frame. What’s the best way to build a wall frame so it can tilt up in place underneath the floor joists? How can I fasten this wall to the concrete floor?

A: If at all possible, I'd wait a year to finish the basement. This allows some time for the basement to prove that it's completely dry during a wet time of the year. The concrete itself will probably have lost all its original water six to twelve months after the pour, but you want to make sure that the sub-surface drainage system is working correctly. If everything checks out, then you've got the insulation issue to deal with. You could build a wall on the inside of the existing insulation, but you'd be much better off removing it, building a stud wall against the masonry basement wall, then reinsulating from floor to ceiling within the wall cavities. Rigid foam (used without any wall frame) is the best basement insulation product going, but since you've already got half the fiberglass you need, you might as well continue with more. Plan to build a wall that's slightly shorter than the ceiling height, and then fill the gap underneath each overhead joist with wooden shims. You won't need much of a space, though. You'll find 1/4 inch is plenty. Slather some carpenters glue on the wedges before driving them home, then secure the connection with two #10 x 3 1/2” screws driven up into each joist. The best way to anchor a wooden wall to a concrete floor is with construction adhesive and powder-driven nails. These are fired into concrete by a small charge of gunpowder carried by what looks like a .22 caliber blank. Powder actuated nail guns are fast, safe and fun to use. You can rent the required tool, but basic models aren’t expensive to buy, either.