Wood Stud Walls (Xpress II and X3-R)

From Garaventapedia

The upper rail needs to be attached to a 2" x 8" board and the lower rail to a 2" x 4" board. The boards are mounted to the wall parallel to the stairs and must be fastened into every available wall stud with minimum two screw fasteners.

Note: Not Suitable for Steel Stud Applications.