Shower floor tile

[badeb]

I am having a slab poured for an addition - the bathroom will have a sunken (4 inch) shower stall area - Does a membrane need to be put down before tiling the floor of the shower or can the tile be set directly on the concrete?

I would appreciate any advice.

[mark Ransley]

you tile on concrete , not a rubber membrane. You would use the membrane before you pour the concrete, under the concrete.

[Jeff Cochran]

Normally, sloped concrete, then membrane, then a mortar bed, then tile.

Jeff