Proper Framing & Insulation for Basements

Testing for Moisture

• Wood framing must only be applied to basements that do not leak. Otherwise the framing members might decay. A good method for testing a basement for leaks is to tape a 2 foot square piece of plastic sheeting onto the concrete foundation walls and leave it in place for a few days. If moisture appears on the front of the plastic, its only condensation, which is not a cause for concern, but if moisture accumulates on the back, water from the outside has found a way into your basement. All leaks need repairing before any framing begins.

Applying Insulation Panels

• Framing a basement starts with the application of rigid foam insulation panels onto the concrete foundation. The panels are fastened to the concrete with a special adhesive made specifically for putting up rigid foam insulation. Regular construction adhesive is not effective. Any gaps between the panels should be caulked. The panels might need cutting to fit around any obstructions. Any empty spaces that remain need filling with smaller pieces of insulation.

Framing the Walls

• The framing for the walls should start with the wooden walls set 1/2 inch away from the foam insulation. The top plates fasten to either the ceiling joists or wood blocks attached to the joists with nails, while the bottom plate anchors to the floor with screws. Measuring the studs to length, spacing them 16 inches apart and toe nailing them to the plates completes the wall assembly. For walls longer than 8 feet, a spacing of 15 3/4 inches for the studs helps the drywall fit better when you add it later.

Installing Fiberglass Insulation

• Fiberglass batting insulation placed into the cavities between the studs increases the resistance to heat flow, or R-value, of the framed wall. Fiberglass batting, or blankets, generally have a layer of vapor retarding material on one side. The batting should be installed with the vapor retarder facing toward the heated area of the home. Framed walls covered with fiberglass insulation should never be left exposed. They need covering with a finishing material, such as drywall.