Plycem is a fiber cement board widely used in modern construction to replace:

This product offers architects, builders and tile contractors a strong, water-durable tile base for tub and shower areas. Also an ideal underlayment for tile on floors and countertops in new construction and remodeling. Board is readily applied over wood or steel framing spaced 16 in. on center with corrosion-resistant wood, steel screws or hot-dipped galvanized roofing nails. After joints are treated, wall or floor tile is applied using latex-fortified mortar or Type I organic adhesive.Noncombustible,water durable and mold resistant.