Shaftwall systems are used to aid in the construction of elevator shafts, mechanical shafts, stairwells, air return shafts and horizontal membranes. The system is designed to use with 1” gypsum board. MBA’s shaftwall is available in 2-1/2”, 4”, or 6” sizes. Shaftwall is available in 18 and 33 mil thicknesses (25 20ga.).