The Proper Way to Frame a Wall Against the Foundation in Your Basement

Measure the wall with a tape measure and use measurements to determine if the wall is square. Measure 3 feet along one wall, 4 feet along the abutting wall and between those two end points; if it is 5 feet, the wall is square. Measure 4 inches in from the wall on both ends and snap a chalk line to make space for a base plate.

Waterproof the foundation wall. Tape a sheet of plastic about a foot square on the wall and leave it 24 hours to see if it accumulates moisture. Adapt a waterproofing method based on the amount of moisture. Paint the wall with a high-quality waterproofing paint if no moisture is collected. Install a waterproof membrane if moisture is a problem.

Cover the wall with rigid foam board insulation. Use unfaced board, with no moisture barrier. Fasten it to the foundation wall with an adhesive recommended by the manufacturer. Seal the seams of the panels with tape provided by the insulation manufacturer. Fasten a two-by-four standing on a 2-inch edge to the wall with concrete screws driven with a screw gun at the bottom of the insulation panels for a 2-by-2 wall.

Nail or screw 2-by-2-inch top plates to the joists at the top of the wall. Mark positions for vertical studs, at either 16- or 24-inch intervals, and secure 2-by-2 studs with toenails driven diagonally to the top and bottom plates and three concrete screws in between to hold the studs to the foundation wall. Put a dab of waterproof caulk over the screw heads.

Cut foam board panels to fit between the 2-by-2 studs. Secure this with adhesive to the studs and outer insulation panel. Cover the wall with drywall.

Build two-by-four walls with top plates fastened to the ceiling joists with 16d framing nails or galvanized screws and bottom plates secured to the floor with concrete nails or screws. Run a bead of caulk along the outside bottom edge of the bottom plate for extra waterproofing.

Mark the top and bottom plates for studs at 16- or 24-inch intervals. Toenail studs to top and bottom plates with framing nails; the result should look like a conventional stud-framed wall. Put fiberglass insulation in the gaps between studs. Use unfaced batts to prevent a moisture buildup between the inside and outside of the foundation wall. Cover the wall with drywall.