Tub Surround Options for waterproofing.

[johnnyLUNG]

I just installed a tub in a 3 wall alcove and have been wrestling with how to waterproof the surround. I have 3 options available to me and thought I 'd throw it out there to see what you guys thought was the best option. I think all 3 work, but I keep on waffling on which to choose. What do you think?

1) Roofing paper layered properly on studs and sealed to tub rim. Cement board on top. Joints taped. Then tile.

2) Cement board on studs. Joints taped. Coat with Redgard, then tile.

3) Cement board on studs. Kerdi, then tile.

I've heard Kerdi is best, but it's obviously more expensive and I have a hard time finding it in a store. I'd probably have to order online. Regardless, any opinions would be very much appreciated. I'm just a DIY'r trying to do right. Thanks in advance.

John

[jadnashua]

Any of those would work and are approved methods. You can use plastic, if you prefer, rather than the roofing felt. Assuming the tub has a tiling flange, as long as the vapor barrier laps over it, it doesn't actually need to be adhered to the tub lip. If it doesn't have a tiling flange, you might consider an add-on kit. Or, if you decide on Kerdi, you could use one of their Dilex expansion joints at the tub edge (and in the corners, if you want), and not have any need for caulk. Industry standards call for caulk on the changes of plane or materials, but an engineered expansion joint works, too. Keep in mind, though, that the expansion joints really want nice, square, plumb corners. If you don't have those, probably better to go conventional with caulk.

CBU tends to suck up moisture from the thinset, so it's often a good idea to wipe it down with a wet sponge to both remove any dust and dampen it a bit - not wet, just slightly damp.

[sue4072]

we have remodeled our three bathrooms ourselves last year. i would highly recommend Wedi board , they are expensive as Kerdi but you should be able to locate them easily. They have a website. It is also very easy to work with than cement board.
http://www.wedicorp.com/

[johnnyLUNG]

Thanks for all the feedback. I appreciate it. I do have the Kohler tiling flange, but it's what is causing a bit of anxiety. I found it a bit cumbersome in application and seeing as the tub has rounded corners, it is proving difficult to get a good square corner out of it. It does specifically say in the instructions that in the end, it should be completely covered with 100% silicone so I suppose I won't see it. But making the round corner into a square one has really been a challenge.

I never heard of wedi board, but but will definitely look into it. Thanks again for all your help.

[jadnashua]

Schluter also now makes Kerdiboard, which is similar to Wedi. Both are foam cored panels (in various thicknesses depending on application up to 2" thick for structural benches, etc.) that are waterproof and are designed to be tiled. Both are easily cut. Both require you to seal the screw penetrations used to attach them and to seal the joints of the panels. Because the Kerdiboard is a membrane rather than a coating, it's a little tougher to cut (just make sure the knife is sharp!) and a little tougher to ding up.