Hi:

I just found this forum and it seems very helpful. I'm in a bind and hope you can help out. I've installed sinks and vanities, and replaced faucets, but that's about the extent of my skill and experience. Now I have to do a bath remodel of my house.

Long story short is that made a poor decision on hiring someone whose credentials I didn't check, and now my bathroom remod is partially done. I need to correct several mistakes in the plumbing and wall tile prep for sure, but I may be OK with the floor tile prep. As to the wall prep.

On the tub surround walls, the contractor mounted 1/2" hardibacker directly to the bare wood studs. No waterproof membrane was used. Also, he didn't tape the seams of the Hardibacker before putting up the tile. I stopped the contractor when 1/4 of the tiles were put up and saw that some of the tiles weren't correctly spaced. We then removed the tiles and now the lower half of the 5' wall is covered in dry thinset, which has covered all the screws holding the hardibacker. Because of this, removing the hardibacker will difficult, but I guess I'll have to do it if I want to put plastic sheeting or roof paper behind the hardibacker.

I just learned about Red Guard, and this sounds like an ideal solution. It sounds like I can just leave the hardibacker on and seal it with two coats of Red Guard; after that I just put the thinset on the Red Guard surface and tile, right? Of course, I'll fill and tape the corners with thinset/fiberglass tape first before putting on the Red Guard.

The Reg Guard should be stable enough to stick properly to both the Hardibacker and the wall tiles, holding up all that weight right? I just want to make sure I'm doing this right.

 

I think you have it right....but the film thickness of the Redguard is very important as I understand.

Possibly an easier solution might be Kerdi membrane?

Pros will be around later.....wait for the experts.

 

Thanks for educating me on Kerdi. I think my head's about to explode from all the new stuff I'm learning.

 

Skip the Red Guard and use Laticrete 9235. It comes with a reinforcing fabric for your seams and corners.
Bear in mind these membrane systems provide a secondary defense against ambient moisture and leaks. They must be applied over the backerboard which overlaps the tub flange.
The first line of defense is a well grouted and sealed tile job. I like to use a color-matched sanded caulk on inside corners and where tile meets tub rim.
Yearly maintenance of grout sealer and caulked areas is recommended.