A.There is almost no difference in the bearing capacity — the wall’s ability to support a compressive load, which is how most walls are loaded. Bearing capacity is a function of the footprint area of all the studs in a wall. For example, a 4-foot section of wall would have three 2x4s, but only two 2x6s. The total bearing area of three 2x4s is 15 3/4 square inches; two 2x6s have a bearing area of 16 square inches.

In bending, however, such as from a wind load, a 2x6 wall is considerably stronger.

In tall walls, where column buckling might be a factor, a 2x6 wall would be stronger if a structural sheathing was used. Structural sheathing provides lateral support to the 1 1/2-inch dimension of either 2x4s or 2x6s, but the greater width of the 2x6 makes it stiffer in that direction. If the sheathing is not structural, both wall systems would have equal resistance to buckling, since the buckling would occur across the thickness of the member.