These portions of your bathroom will be constantly underwater, so they need additional layers of protection. 13-5/8 in. Drywall should not sit directly on the tub as it can 'wick' moisture and will eventually fall apart (even green board) if the tub is not kept caulked properly. And if the drywall will be submerged, add waterproofing behind the wall. This last feature is essential for bathtubs , shower enclosures, wet rooms, and sink. The drywall used in bathrooms is most often "greenboard," which has a moisture-resistant coating but isn't waterproof. The cement board should be the same thickness as the drywall—for example, 1/2 inch thick cement board if the drywall is the standard 1/2-inch thickness. Fixing drywall above a shower or bathtub entails removing the damaged area completely, patching it and then making it as watertight as possible. There is no need for drywall behind the cement board and I have never heard of it being done that way. question is Doing so will only make filling and taping much more difficult. With its 15/16 in. Then apply a generous amount of thin-set to the bottom bathtub tile and position it 1/8 in. Access Panel For access to commercial or residential plumbing, For access to commercial or residential plumbing, electrical wires or cable elements the Everbilt EB series 13-5/8 in. x 13-5/8 in. The insulation behind the tub or shower should be equivalent to the insulation in the rest of the exterior walls and should be covered with an air barrier of cement backer board, rigid foam insulation, or non-paper-faced drywall that is sealed at the edges and seams to provide a continuous air seal. Cut a piece of cement board to fit the wall cutout, allowing for a 1/4-inch gap between the cement board and surrounding drywall. DEAR JOHN: There seems to be a significant amount of confusion about drywall, water-resistant drywall, and wallboard that is 100-percent waterproof. Tub or shower surrounds require routine care to keep grout joints waterproof and seams between tile and shower base or tub sealed with caulk. Loose bathroom wall tiles, or a wet spot on the bedroom or hallway side of your shower wall, indicate a problem with moisture. The proper framing must be installed behind the edge of the drywall and the flange. How to Replace the Sheetrock Around the Shower & Bathtub. The best approach when installing cement board or other tile backer around a tub is to keep the cement board out of the lip area. x 13-5/8 in. Walls and Ceilings - drywall behind tub surround - hi all. I have green board to install around the tub for backing. access panel will conceal the clutter while providing a safe means of access to important components of the building or home. above the tub. I installed a new bathtub and plan to use a glue up tub surround. If the tiles are mounted on drywall, the moisture will eventually turn the drywall to a messy mush. above the lip of the tub. Also, be sure to use a water proof, or water-resistant drywall around tubs/showers. Once water seeps into the tiniest crack or gap, it will start to crumble. Cement board can be easily cut with a circular saw. Apply it to the wall with the bottom edge about 1/4 in. Water easily degrades drywall, so you must seal the edges to prevent moisture from entering the wall space behind the drywall. Generally, the surfaces around the bathtub are tiled, which provides superior water resistance, and are easy to clean. But some bathtubs have drywall surrounds. TIP: When choosing drywall pieces to hang around the tub/surround, never place a recessed edge up next to this void.