Intermediate framing is a simple and easy way to make the exterior wall assembly about 3% more efficient and reduce the number of cold spots in the walls while reducing the cost of framing–all without significantly changing framing methods.
Framing material using traditional methods takes up about 23% of the total wall area. Making that 23% more energy efficient can really make sense.
Intermediate framing methods alter traditional framing in two ways: the connection of walls at the exterior to one another and headers. The typical layout of studs 16” on center and double top plates remain.
Exterior wall corners in intermediate construction are framed by using three studs turned so insulation can be installed all the way to the outside of the corner. Two stud corners can also be used with drywall back-up clips or backing made from lumber scraps.
Junctions between exterior walls and interior partitions are made without use of the traditional three stud post. A single backer board may be used, horizontal blocking or “ladders” between studs on the exterior wall, or drywall clips. Use of horizontal blocking or “ladders” allows scrap material to be used rather than paying to dispose of it. Insulation is able to fully fill the cavity instead of being interrupted by extra studs.
Voids in headers are insulated with rigid insulation with an insulating value of at least R-4. More header voids can be created by using only the minimum number of header pieces required for structural reasons. For example, a single 2 x 12 may safely span the opening rather than three 2 x 12’s. Depending on the snow loading, 2-2 x 12’s can span an 8’ opening carrying a roof and ceiling of a 28’ wide house. Leaving off the third member will allow 2-1/2” for rigid insulation to be installed cutting the heat loss through the header by more than 3 times.
Of course, non-load bearing walls do not need any headers at all and the entire space can be filled with insulation.
The beauty of intermediate framing is little has to change yet significant energy savings can result. It also uses less framing material.