[zoiberg137]

So I have a basement bathroom with concrete walls. I am trying to figure out the best/least expensive way to tile the walls for a shower. I keep getting different opinions on this. I know I can install furring strips, hardie board, tape and redgaurd and then tile over that. That was my original plan, but then a contractor friend asked me why would I want to spend the money and time doing all that work, when I already have concrete walls? he suggested that I just smooth out the existing concrete walls (their a little bumpy) with mortar mix or ardex feather and then tile directly on that. But then...someone at the hardware store insisted that I have to have some type of vapor barrier, and that if I didn't want to deal with furring strips I could just use thinset and screws to mount hardie board directly on my concrete wall, tape it, AND THEN stick ditra mat over that and then tile directly over the detra.

So...too many opinions, and I am confused. With being $85 a roll, Im really not crazy about using ditra for anything. Im not opposed to putting hardie baord directly on the concrete and then doing tape and redgaurd...but I don't get what the different would be between the hardieboard and my original concrete wall.

How about... I just smooth out my bumpy concrete walls with mortar mix, roll on 2-3 coats of redgaurd directly on the smoothed concrete, and then tile with thinset? Any issues with this plan? I should add that my walls are perfectly dry as-is...no moisture getting in from outside. My house was built in 1906 if it makes any difference...

Thanks for any and all help!!!

 

[JazMan]

Hi,

The hardware person should stick to what they know best. We do not install concrete backer to concrete substrates. Ditra is not for walls and never for showers. Ditra is only $85 because it's a small 54 sq. ft. roll.

You can fix the wall as you said and apply Redgard or other liquid membrane, or good with Kerdi membrane. Redgard is easy to find and the cheapest of the liquid membrane that I know of. It's not that much cheaper than sheet membrane though since you should apply 2-3 coats. But, it's under $50 gal. which id cheap, you'll probably use 2 gal.

Before you continue however, how you do this really depends on how the floor and curb will be done.

BTW, smoothing out the bumps is not the goal. You need to make the walls flat, big difference.

Jaz