Mastic for shower wall tiles

ashton44

Ok so I am just about to start tiling (tomorrow hopefully) my newly constructed bathroom shower/tub. I have put up concrete board. I was told by a manager at Home Hardware to use mastic in the shower for the tile because it is much easier to use, etc. etc. I just had Mike Holmes on in the background and heard him say never to use Mastic in wet areas. So I jumped online quick to read up on it and saw a few blogs on here saying never to use Mastic. Two questions:

A) If it is Mastic that is meant for wet areas is that ok or should I use dry un modified thinset?

B) I have already used the Mastic over the joints in the concrete board. Can I now change to thinset or will it not adhere where the mastic is?

I'm annoyed because I already spent $50 on the Mastic but I want this done right.

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joecaption

Take it back, never that a box stores advice. But while your there pick up the Red Guard you forgot to pick up to water proof the tile board.
Tile board is not water proof.

JetSwet

Definitely easier to work with tile glue then using thinset although no one here will recommend using it anywhere except backsplash on kitchen.

I have use it in showers and none has failed although I don't anymore just because its over all not a good idea.

What size tile are you using? I say if your already using the tile glue then let hope your tile size isn't any bigger then 4-6"