The standard rule for framing has changed from 2 × 4 to 2 × 6, to allow for more insulation, and while most handymen and contractors use the traditional method of framing there are some advantages to using an unconventional framing technique.
Standard framing involves using 2 x 6 lumber nailed at 16 inch centers to a bottom plate and top header, see Figure 1. Holes are drilled in each stud to allow for the installation of electrical services, media centers, cable TV, and telephone. Then insulation is placed between the studs.
The outcome is that the studs provide a method of transferring heat and cold from the outside of the home to the interior. Wood, relative to other materials, is not have good thermal insulation qualities.
An unconventional method of framing is growing in acceptance. This method uses 2 × 6 lumber for the upper and lower plates, ends of the walls and to frame windows and doors, but uses 2 × 4 lumber as the stud size, offset between the interior and exterior wall, see Figure 2. This provides a barrier against heat and cold transfer through the wood wall studs, as air is an excellent thermal barrier.
Figure 1 - Traditional 2 × 6 framing on 16 inch centers
Figure 2 - Unconventional framing using a 2 × 6 frame and offset 2 × 4 studs
The unconventional method of framing also makes it easier to run all electrical services as there is no need to drill any holes, the wiring can just weave its way through the 2 x 4 studs and be fastened to the edge of the stud using wire staples.
Insulation covers the complete wall, less the end studs, which will provide better interior temperature regulation at reduced energy costs.
Noise is reduced because there are fewer pieces of wood that directly connect the exterior to the interior. Sound transmission between the exterior is dampened by the insulation. This would be highly advantageous in multi-unit dwellings.
Why don't more people use this method? There is more material used, and more nailing of studs, hence the labor cost is greater.
If you are considering building a home or an addition to your current home, you should consider using offset 2 × 4 studs for the exterior wall construction.