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-   -   Preslope in tiled shower (http://www.diychatroom.com/f7/preslope-tiled-shower-139344/)

gbook2 04-05-2012 02:16 PM

Preslope in tiled shower
 
I'm renovating my bathroom, which has a 3'x3' shower. I've torn out all of the old material, but I stopped when I got to the drain. I called in a plumber to replace the cast drain trap with PVC so I could use a PVC 3 piece drain. The head plumber and the person who came to do the work today said "no no, you want to lay the shower pan liner directly onto the subfloor, then put a mud bed on top of it. Flat is the way to go."

They're both suggesting the best way is to lay the pan liner on the plywood subfloor, with no preslope mud underneath the pan liner. They said I should add 0.75" of plywood to the subfloor though to make it sturdy. This still doesn't seem right after they explained it to me a few times. It seems the purpose of the pan liner is to be the ultimate catch all for water... so, shouldn't it slope toward the drain weep holes? If I lay it flat, any variation in the sub floor could cause pooling of water in the liner that would never go into the weep holes. Their suggestion would only slope the mud that goes on top of the liner.

Is this a valid way to tile a shower: to not use a preslope under the liner??

DannyT 04-05-2012 08:46 PM

they were wrong. many have been doing it that way for years tho. do the preslope under the liner and you wont have any problems.

oh'mike 04-05-2012 08:52 PM

Building a shower pan with pre-sloped mortar bed, liner and curb.

This is the correct method---many pans are build wrong--

gbook2 04-05-2012 10:02 PM

That's the feeling I got. That no-preslope wasn't a bad way to build a shower base, but there are better ways.

Alan 04-05-2012 11:05 PM

Out of all the people around here that do shower pans, i've only ever seen one guy build a pre-sloped pan.

I'm pretty sure the plumbing code requires that the liner be sloped to drain but i'd have to check on that. Regardless of the validity of my last statement, a sloped liner is a much better idea.

oh'mike 04-06-2012 07:28 AM

I believe that code only requires a pan to pass a flood test-----

The tile industry and experience tells us that the preslope is needed to keep the pan dry and mold free----

framer52 04-06-2012 08:56 AM

Mike, your reference was one of the best i have ever seen, thanks for posting it.

Alan 04-06-2012 10:19 AM

Quote:

Originally Posted by oh'mike (Post 892850)
I believe that code only requires a pan to pass a flood test-----

The tile industry and experience tells us that the preslope is needed to keep the pan dry and mold free----

My Oregon residential plumbing specialty code (based on UPC) Says :

411.8 (2)

"All lining materials shall be pitched one-quarter inch per foot (20.9mm) to weep holes in the subdrain of a smooth and solidly formed sub-base."

:thumbup:

oh'mike 04-07-2012 07:17 AM

Good to see that----


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