Hi Susan: To add a preslope to your shower would require demo up to 12 above the floor so the linercould be put behind the moisture barrier behind the so called cement board. So the steps would be
1. demo walls 12 to 24 inches above floor tear out old liner and curb if you have one
2 install preslope which would probably mean tear out old drain to raise it to the height of the preslope
3 install liner properly on top of preslope and up walls 10 to 12 inches behind wall waterproofing
4. reattach cement board to walls keeping 1/2 above liner with no nails in liner!!
5. cover liner with cement to form pan being careful to make sure weep holes are open. this layer locks in the bottom of cement board so it needs to about an inch thick
6 retile and watch the mastic on the walls fail. But this may take a couple of years...then tear out and redo with a proper kerdi system shower... sorry

Sakcrete is a brand name. It doesn't tell me what was used. They make a variety of cement mixes. If they use the concrete products, it was the wrong stuff. You can use their Sand mix with additional sand to make deck mud. I don't want to get into specifics because they may sell different products in your area than mine.



I have never done a "modified" Kerdi system before but hopefully someone else can advise you if they have. I foresee a problem with the Floor/wall joint with just doing a kerdi pan without the walls since the kerdi does not go behind the durock like the liner would.

If you do use kerdi, you should replace the drain with a Kerdi drain. Decide on which system you want to go with and then check back with us to discuss specifics

Yes, a properly installed preslope will prevent water retention. The kerdi system will keep the shower even drier since the water proof membrane will be just behind the thinset holding the tiles in.

Do you know if a moisture barrier (6 mil poly) was installed BEHIND the durock?

As the previous post mentions, you have to demolish the wall high enough to allow the new pan to go in AND allow the new Durock to be joined into the old.

Since the tiles are mosaics, MAYBE the mastic had enough to dry, time will tell. I do understand your hesitance to rip everything out because of the cost. At least you will be more informed next time.

Hi again. In the time since I haven't written, we have demolished the shower floor down to the shower liner. Pictures will be posted tonight....

The liner and mud was soaking wet. The tiles were clearly getting wet from beneath.

Now my questions are
1. How can you tell is its pre-sloped under the liner? It appears to me that there is only a sloping around the drain.
2. in the rebuild, what about putting a layer of LADACREAM 32/95 between the mortar and the tile if the new mortar mix is a heavy sand and portland cement mixture?

Should there be any folds in the liner at the wall junction?

Stand by for pictures! they were taken every five minutes for a half an hour to show the water retained in the pan.

thanks everyone!
Susan

I haven't read this whole thread, but if you see a tapered mud bed under the liner then thats the preslope. There should be folds in the corners when using a liner.