I am renovating my bathroom and am getting close to tiling the shower. I have the hardibacker in place and mortared the seams etc. The guy at Home Depot made it seem like I needed to apply a waterproofing before laying the tile (RedGard 1 Gal. Waterproofing and Crack Prevention Membrane). This stuff isn’t exactly cheap but I don’t want to end up with a leak somewhere. Is this stuff needed or was the rep just trying to make a sale?



It is absolutely needed.

Tile, mortar, and cement board are porous by design so that water and vapor can pass through them.

Using a membrane keeps water from invading your framing and structure. I personally recommend Kerdi, though instead of redgard.

  • I have looked for something similar at Lowe’s but couldn’t find anything. Is there a generic term I should be searching for? – Steve Salowitz Mar 11 '18 at 18:22
  • Kerdi is a brand of waterproofing membrane. Lowe's should carry it, or you order online – Matthew Mar 11 '18 at 21:58
  • I would stick with the Redgard, it does work and more user friendly for the DYI'er. It can get real messy, but so can installing the Kerdi. – Jack Mar 11 '18 at 22:43

It's needed, at least, strongly suggested if you have dry-walls, if you're on a brick&concrete house you don't need it.

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