Less Can Be More for Wall Framing

Here’s one energy efficiency feature that costs no more than standard construction.
In typical wall framing—with studs 16 in. on-center, lots of trimmers, cripples and assorted nailers—as much as 23 percent of the wall is wood and 77 percent is insulated cavity. By eliminating excess framing material, you can increase the amount of insulated cavity to 83 percent and cut the wood to 17 percent. Cutting back on the framing saves on labor and materials.

It also improves energy performance, because wood loses heat three times faster than a batt of insulation. Everywhere a stud touches the inside and outside surfaces of the wall, there’s a “thermal bridge” that allows rapid heat loss.

The techniques below reduce the amount of framing lumber and increase the amount of insulated cavity. That increases the overall insulation value of the wall. It also eliminates traditional “cold spots,” such as corners.

Fortunately, you don’t have to sacrifice structural integrity for these cost and energy savings. These framing methods are allowed under virtually all building codes. However, be sure to note these techniques on your plans when you apply for a building permit. Local codes may have specific requirements.

The basic principle of eliminating structurally unnecessary framing lumber goes back to the 1960’s when the National Association of Home Builders Research Foundation developed the Optimum Value Engineering approach. OVE is explained thoroughly in the “Construction Cost Savers” series of six publications distributed by Southern Forest Products Association, P.O. Box 52468, New Orleans, LA 70152.

This article appeared in Energy Source Builder Vol. III No. 6, December 1991,
©Copyright 2008 Iris Communications, Inc.