what thickness wonderboard for bathtub walls
How to Install Cement Backerboard around a Tub. Bathroom Remodeling For Dummies. The ideal underlayment for ceramic tile is cement backerboard, which comes in 1/4- and 1/2-inch-thick panels measuring 3 x 5 feet and 4 x 8 feet. The dense, gray material is very heavy, so use the smaller size for replacing tub walls.