Tips for fiber cement board installation

Install cement board or an equivalent moisture-resistant backing material on walls behind tub and shower enclosures composed of tile or panel assemblies with caulked joints. 

• Don’t use paper-faced backer board, i.e., paper-faced drywall, behind seamed tub and shower enclosures.
• Use an alternate approved product such as fiber-cement, fiber-reinforced gypsum, glass mat gypsum, or fiber mat-reinforced cementitous backer panels.
• If a monolithic tub and shower enclosure (e.g., fiberglass with no seams) is used, a paper-faced backer board can be use if it meets ASTM mold-resistant standards (ENERGY STAR).

Selected from: https://basc.pnnl.gov/resource-guides/cement-board-installed-behind-tile-and-panel-tub-and-shower-enclosures