Replies

1. 
   Karl | Apr 13, 2009 09:09am | #1

   I would consider sawing the shower perimeter and removing the concrete in that area. Install your plumbing and place your drain, get the height where you want it and place some fresh concrete in the hole with some fall toward the drain. Waterproof the presloped concrete and pack mortar over it to the height and slope you want for the finished shower floor.

   I have undoubtedly missed a critical step or two but I am trying to illustrate what seems a lot simpler and more effective than trying to grind a slope.

   A cheap diamond blade in a skill saw might work or rent a gas concrete saw.

   Try the john bridge forum and I am sure they have people on the forum who have done something similar.

2. 
   Huck | Apr 13, 2009 09:11am | #2

   I want to know if it is feasible to grind down the slab to get fall rather than building up a shower pan

   I don't think it is.  What's wrong with sloping a cement base from the curb (or wall) to the drain?  Is this going to be a curbless shower?

   lack of waterproofing where the floor meets the wall

   There are waterproof membranes made for this application. 

   "...craftsmanship is first & foremost an expression of the human spirit." - P. Korn

   CaliforniaRemodelingContractor.com

3. 
   rdesigns | Apr 14, 2009 01:02am | #3

   Sounds like you might be considering using the concrete, after it's ground down, for the actual floor of the shower? Or not? If not, are you tiling over the concrete?

   I hope you're planning on tiling over the slope that you create. If so, you can solve the problem of slope much more easily, and, as someone else mentioned, you will use a membrane shower pan liner to deal with the junction of floor and wall.

   You could create the slope using dry-pack mud (sand and cement, no lime). Tip: use a wood float to trowel the dry-pack and you won't bring a soupy mix to the surface that is hard to trowel.

   Lay expanded metal mesh on top of the existing concrete (under the dry-pack) to help keep the thin layer of drypack from cracking. Paint it and the existing concrete with latex concrete bonder before applying the dry-pack.

   If you have to chip out some of the existing concrete to get access to the drain in order to install a proper pan shower drain fitting, the patch will be covered with the dry-pack, as well. The pan shower drain fitting will have a clamping ring that sandwiches the membrane between the clamping ring and the "pan" part of the shower drain fitting.

   Have the membrane material plenty high--at least 3" above the FINISHED threshold height.

   Flood-test the membrane to check for leaks.

   Now you're ready to go to the next steps of the mud base and tile.

4. 
   geoffhazel | Apr 14, 2009 01:08am | #4

   You're going to have to jackhammer the concrete out to get in the plumbing anyway, so if it was ME, I'd make saw cuts to the size of the pan, then remove ALL the concrete underneath, put in my plumbing, and then use a WEDI pre-formed pan and put the WEDI board on the walls as well. It makes a watertight membrane when sealed with the WEDI (urethane based) caulking, and is coated with cement for good adhesion to the tile. You'd have to backfill the hole with some cement to get the height right for the wedi pan but it's only 1.5" thick, if you're doing a typical 3x3 pan, it would just be a few bags of premix. You're gonna need something to fill in the ditch where the outflow is anyway.

5. 
   JeffBuck | Apr 14, 2009 01:16am | #5

   sounds like a great place to set a cheap fiberglass pan and be done with it.

   Jeff

       Buck Construction

    Artistry In Carpentry

        Pittsburgh Pa

1. 
   eleeski | Apr 14, 2009 01:34am | #6

   I have an outdoor shower that needs to drain properly. Occasional use and no soap. As long as the water doesn't back up against the wall I'd be OK. But when the slab was poured with a drain, the slope was blown.

   What were you planning to use to grind a slope? I'd need to lower the drain by about 1/2 inch. I've seen sidewalk grinders that smooth out discontinuities in sidewalk cracks. Would that tool work and where can you rent one?

   My old plan was to cut relief grooves in the concrete to get it to the drain.

   Eric

6. 
   babypop | Apr 14, 2009 06:30am | #7

   Thanks to all for your input.  I failed to clarify a few things in my initial post.  I already have the 2” waste line in the middle of the 3’ x 5’ shower area.  Yes, I was indeed hoping to use the ground down slab as the actual pan allowing a curbless shower (ground down agg cool look kinda deal sealed up real nice).  That would then create the issue with the drain as there would be no clamping ring or membrane to sandwich.  Just straight drain to waste pipe and slab.  Therefore no membrane would be used to accomplish the floor to wall transition leaving that issue as well. 

    

   Sooo, what I’ve got so far as options are the drypack/membrane/mudbase/tile (traditional?); the WEDI preformed system and tile; or the cheap fiberglass pan.  While it is “just” a shop, I want it to be nice.  That leaves me between some potentially impossible ground slab, traditional or some sort of pre-fabbed base.  The WEDI site makes it look bombproof and super easy and waaaay expensive.  Is it all those things?  Traditional sounds doable but very labor intensive and potentially highly frustrating for a first timer. 

    

   Further thoughts/advice?  You have my thanks in advance. 

1. 
   geoffhazel | Apr 14, 2009 06:37am | #8

   I don't know how waaaaay expensive wedi is, but it is bombproof with 10 year guarantee, tile right over it once it's on the wall. I went to their certified installer class that was supposed to take 1 1/2 hrs and we just kept going and talking while the instructor put together a full 3' shower while he talked. I'd say you could put wedi on the walls and caulk, but they like to set the side panels into grooves in the pan a bit to get a double-seal side and bottom; that would be some tricky grinding!

2. 
   rdesigns | Apr 14, 2009 05:19pm | #9

   Check out the available sizes for a fiberglass base. They're cheap, and it would cover any concrete patching you'd have to do to get the drain centered exactly where it has to go to match the drain opening in the base itself.

   They're easy to clean, they make the transition from floor to wall, and for any shop, they're nice looking. You can tile the walls above. Or, you could install a 4-piece unit (base, back wall, and 2 side walls.) Owens Corning makes several models of the 4-piece unit.

3. 
   joeh | Apr 14, 2009 05:38pm | #10

    I already have the 2” waste line in the middle of the 3’ x 5’ shower area

   Got a trap in that line?

   Joe H

1. 
   babypop | Apr 15, 2009 12:11am | #11

   GH - I was checking the system and you are right. That would be some serious crazy trick grinding. It's so crazy, it just might work ; ) I found a local WEDI joint that I'm going to check in on pricing/sizes/etc.RDesigns - I'm also gonna check out the OC stuff as it sounds like it would simplify a bunch.JoeH - Boy, that would sure suck if I didn't, huh? Fortunately: p-trap --> check Thanks again, everyone.