is a pre-slope required for slab shower - DIY Chatroom

memjeff · 11-11-2007, 06:11 PM

We ripped out our old shower and whirlpool tub and are planning to build a shower all the way across the back wall (see red outline in picture below). The plumber has already moved the drains and plumbing. I will be building a shower curb and bench out of pressure treated 2x4s.

Two questions:
1. The plumber is saying that we don't need a a preslope mud bed under the liner. The tile man is going to put a mud bed in on top of the liner but every book/post I see shows that we need a prebed below the liner. Is a pre-bed required?

2. The plumber also says he wants the concrete board attached to the walls before we install the liner (so the liner is not damaged). He says to leave 6 - 8" off of the floor so he can attach the liner to the studs. Again the books I have read say that the liner needs to go in and then the concrete board goes over that. Can it be done the way the plumber says?

Matt C · 01-16-2009, 05:31 PM

Quote:

Originally Posted by memjeff

We ripped out our old shower and whirlpool tub and are planning to build a shower all the way across the back wall (see red outline in picture below). The plumber has already moved the drains and plumbing. I will be building a shower curb and bench out of pressure treated 2x4s.

Two questions:
1. The plumber is saying that we don't need a a preslope mud bed under the liner. The tile man is going to put a mud bed in on top of the liner but every book/post I see shows that we need a prebed below the liner. Is a pre-bed required?

2. The plumber also says he wants the concrete board attached to the walls before we install the liner (so the liner is not damaged). He says to leave 6 - 8" off of the floor so he can attach the liner to the studs. Again the books I have read say that the liner needs to go in and then the concrete board goes over that. Can it be done the way the plumber says?

You absolutely need a pre-slope. In most states it is required by building codes. The cement board goes on after and over-lapping the pan-liner. You can't fasten just the bottom pieces of cement board later because you aren't supposed to puncture the liner with fasteners. Pre-slope, Liner, cement board, top layer of dry-pack, then the tile.

**thekctermite** · 01-16-2009, 08:57 PM

MattC, although you're 100% right, you're answering a post that is about 14 months old. Happens to the best of us!