I'm preparing to start a shower tiling project. Framing is done, rough plumbing is complete, and the hardiboard is up. I will be using a Schluter shower kit.

Before I start to apply the Kerdi membrane, do I have to "mud and tape" the backer board joints and seams with thinset & acid resistant mesh tape? Or can I just fill in the seams with thinset, smooth it out, let dry before the Kerdi?

Thanks,

FGHUNT

There is no need to treat the seams if you're using Kerdi.

If you have Hardibacker on your walls, you'll want to thoroughly dampen it with a sponge immediately before you start applying thinset. Hardibacker is very dry and soaks up moisture very quickly. It will take the moisture right out of your thinset before you even have a chance to get some Kerdi on the wall if you don't dampen it first.

You may also want to work in relatively small sections if you've never used Kerdi before.

I have found that a mist/spray bottle is way faster for wetting the hardi.

A fire hose is even faster.

I hadn't thought of that, maybe next time.