I am remodeling my shower and have replaced all the old sheetrock with ½” concrete backer board.

What is the best membrane product to waterproof the backer board in the shower before the tiles are installed?

If you don't get any firm opinions in here, go to this web site and ask Harry Dunbar:

http://www.ontariotile.com/

Harry is a ceramic tiling contractor in Barrie, Ontario, Canada that specializes in showers. He has a ceramic tiling DIY Q&A forum on his web site, too. I met him online years ago, but I don't know if he'll still remember me.

But, even though Harry is a tile setter by trade, that doesn't mean he's tried using all the different waterproofing membranes out there. It's very possible that he buys what the supply store he shops at sells, and hasn't been dissapointed enough with their product to have gone shopping for a better waterproofing membrane. That happens all the time in every trade.

I expect that if you pick ANY waterproofing membrane, and put on twice as much, you can be confident that you've got the most impermeable membrane in town. See if Harry agrees.

This message has been edited. Last edited by: Nestor,

Normally, with concrete backerboard, you install a liner behind the backer. You can use a rubber liner but a heavy waterproof material like 30# felt will also work - provided you overlap any seams from the top down.

If you choose to waterproof on top of your backer then the best is probably Schluter Kerdi fabric.

I think he's talking about the water proofing membranes like RedGard that you paint on with a paint roller sleeve.

quote:

Originally posted by Nestor:
I think he's talking about the water proofing membranes like RedGard that you paint on with a paint roller sleeve.

You're probably right. I've never used Redguard but one of my tile guys loves it. Since the backer is already in place, the Redguard or similar product will be the easiest solution.