Backerboards for walls.
Waterproofing the walls behind the tile for showers and tubs is a must. There are several different methods for waterproofing. Applying a liquid membrane with a brush or roller is one method. The liquid membrane has a consistency similar to thick, wet paint. The usual application is to apply one coat and 24 hours for it to dry. When the first coat is dry, then a second application is necessary for effective waterproofing.
A less expensive method is the use of backerboards for the walls. Backerboards are not waterproof but their water resistant feature allows them to keep their shape and not disintegrate from moisture. Backerboards are normally cement or fiber based. Another option is to use sheet boards that are similar to drywall except they have a fiberglass based finish that is laminated onto the sheet board to create a waterproof shield on each side. These boards provide adequate protection but are a bit more work because the seams must be beaded with silicone and and fiberglass mesh tape must be used to waterproof the seams. However, these boards are the least expensive method.
A method that is quickly garnering the professionals’ attention, and a method easy enough to use for novice DIY’ers is a product produced by and available from
Schluter Systems products at SouthShoreFlooring.com. Kerdi looks like and is applied much like wallpaper. It can be installed over plain drywall for a completely waterproof finish not normally heard of for drywall in moisture laden areas like tubs and showers.