Great idea. There is a big issue that was left out completely. What about the exterior siding framin that is required? With the 3 stud system, there is only 1-1/2" on the exterior side of one of the corners. There is no decent home that uses 1" corners. We are usually using 3-6" corner trim which requires a nailing stud. In many cases, the 4-stud corner will accomodate this type of exterior trim/siding package. I understand the insulation argument and agree that it presents an issue. However, the practical side of the overall building process is a bit more complicated in this instance. There is another possibility by using a different type of 4-stud corner that allows for insulation on the corner. It involves using a t-wall set up on the end along with the single stud on the opposite end. The t-wall framing is the same type of 3-stud framing used when framing for interior walls that t into other walls. Using these on the corners allow for the builder to put in 2" on insulation on the corner and helps to alleviate the non-insulation issues presented in the video. It then provides the missing nailing stud on the exterior wall. It's still a 4-stud system, so there isn't any material savings. However, your siding guys will love you!
