Using cement backer board (or cement board) in the bathroom on walls adjacent to the floor is generally a good idea, especially if those walls are prone to moisture exposure or are close to the shower or bathtub area. Cement backer board provides superior moisture resistance and stability compared to regular drywall, making it an excellent choice for protecting the underlying structure from water damage.
Here are some guidelines to consider:
Wet Areas: For areas with direct water exposure, such as inside the shower enclosure or around the bathtub, using cement backer board is highly recommended. These areas are most susceptible to water damage, so having a moisture-resistant substrate is crucial.
Adjacent Walls: Walls adjacent to the wet areas may also benefit from cement backer board. While these walls might not experience direct water exposure, they can still be affected by moisture, especially in bathrooms with poor ventilation or if water splashes onto the walls during use. Using cement backer board on these walls can provide an added layer of protection.
Other Walls: For walls further away from the wet areas and not exposed to moisture, regular moisture-resistant drywall (green board) or standard drywall is generally sufficient.
Ceilings: In bathrooms, moisture-resistant drywall or cement backer board is also commonly used for ceilings, particularly if there is a risk of water splashing onto the ceiling from showers or tubs.
Remember that regardless of the type of drywall used, proper waterproofing measures should be employed in areas with significant water exposure. This includes using waterproof membranes, sealing joints and corners, and applying appropriate waterproofing materials before tiling. Always follow the manufacturer's guidelines and local building codes to ensure a successful and long-lasting bathroom installation.