Next, you’ll tape the seams of the backer board, and apply a waterproofing sealer to the surface before you begin installing the tile. Do I seal cement board before tiling?ĭo you need to seal backer board before tiling? But for a tub or shower, you need to begin with a cement backer board base, because the tile will be constantly wet. On the outside wall, it is generally suggested you cut slits in foil to prevent the “moisture sandwich”. You need to use 1/2″ backerboard for walls…1/4″ isn’t sturdy enough. You need a vapor barrier… either poly, 15# felt or a surface applied membrane like RedGard. On the video provided by hardiebacker, for wall tiling, it says either side is fine although they recommend the rough side. The rough side is the back or bottom…with 1/4 ” hardie there is often scoring lines on the front…1/2″ just has the printing on the front. … However, if you choose to use concrete backerboard, which is much stronger and more durable than gypsum board, a water vapor membrane must be placed underneath it or a sealant applied on top of it. Does backer board need sealing?Ĭontrary to popular thought, tile and grout are not waterproof, and some moisture will penetrate even if sealant is used. Hardibacker doesn’t need a vapor barrier or waterproofing except you do need to tape and thinset the joints. Do I need vapor barrier behind Hardibacker? Similarly, which side of Hardibacker do you score? when you score drywall you snap away from the scored side. If you do use it label side up, we ask that you remove the label before tiling.

Wonderboard can be installed with either side down with excellent results. What subfloor should HardieBacker® cement board be installed over? Is there a front and back to Hardibacker board? Which side goes up, smooth or rough? Either is acceptable, but we recommend that the smooth side with the nailing pattern of every 8″ on center go up. Cement board will not fall apart when exposed to water.

It is extremely hard and waterproof, meaning it will not deteriorate over time when exposed to water, making it ideal for use in high-traffic areas that are susceptible to the adverse effects of moisture.Ĭement board is not waterproof. Most brands of concrete backer-board consist of a fibrous reinforcement cement composition molded into sheets.

Install hardibacker board on subfloor