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Slate tile in shower?

Heck's picture

I went to look at a tile repair job tonight.

12 x 12 slate tile.

The house is 5 years old, and the owners have been having trouble with their shower for 4.

They want it fixed.

Custom walk-in shower. Pre-made pan in drain area (?), with some sort of concrete base sloped from the entry toward the pan (??).

The whole floor is failing, water is standing under/in the tile, it squishes up when you walk on the tiles.

Also the tile is being attacked by a mold/fungus/something that is eating away at  the tiles.

So, is slate not a good idea for a shower floor?

Owner has selected a porcelain mosaic tile to replace floor.

Bench will be completely rebuilt.

How do you price a job like this?


"Citius, Altius, Fortius"


when you are up to yur knees in gators, make gatorade     

(post #101201, reply #1 of 16)

Bet you a dollar the weep holes are plugged up. Horrendous grout job BTW.
On slab or joists? Any damage to the underneath? Pan leaking?
Could also be that the pan is not sloped either. Which will have to be corrected.

I'd explain this possibility and how a shower pan is supposed to work to the HO. Give an estimate for both possibilities.
I got some concerns about how they waterproofed the dam/glassblock???

May not need to tear out the bench though. Tile the top of the bench with the same mosaic tiles as the floor, makes for a nice detail and easier to work with on a small diagonal.

Edited 5/11/2006 12:51 am by LEMONJELLO

__________________________ Judo Chop!

(post #101201, reply #3 of 16)

Hello Lemonjello.  I'm curious about your grout job comment.  I see big gaps between the wall tiles and the floor tiles.  Is this what you mean?

(post #101201, reply #9 of 16)

Joints are kinda big and the curb in the grout at the edges formed in grout? WTHIT???
If you know tile, this job reaches up and smacks you..

(The same reaction that you get when you walk around the corner and your buddy is taking a dump in a drywall bucket) Cringe,shield your eyes, holler some explicative, turn around and stagger away...

Edited 5/11/2006 1:56 pm by LEMONJELLO

__________________________ Judo Chop!

(post #101201, reply #2 of 16)

That's the fault of the shower pan and the substrate, not the tile.  If I were you, I'd scan through this site: and post your question there.

Is there anyway you can look at the shower from below?  I would estimate this including everything down to reframing it. 


"so it goes"


"When we build, let us think that we build forever.  Let it not be for present delight nor for present use alone." --John Ruskin

"so it goes"


(post #101201, reply #4 of 16)

One thing I always try to avoid is the tile on the curb and seat areas. I prefer to use a solid piece of either stone or some sort of solid surface material as I don't like grout joints in these areas, plus I think it looks better

(post #101201, reply #5 of 16)

1. You price it as a gut and new installation. New pan. New drain. New mud slope.

2. You also have a line stating that inspection of substrate will be made and assessment of its condition will be submitted with recommendations regarding repair or modification will be made at that time and are not a part of the Original Contract.

3. Pan shall wrap crub/ threshold, though due to existing conditions, you will be able to only bring pan up to glass block base.

4. Be sure shower seat is totally covered by shower pan and its pan material is inside shower floor pan.

5. Slate is a fine material for a shower.

6. As for existing failureS:

a. The drains weep holes are definitily clogged. This is a lot more common than one might expect. It has to do with carelessness when installing the mud buildup. We typically have a bag of small stones - p-stone - with us. Piling the p-stone around the drain prevents mud debris from getting to the weep holes during installation and in later years.

b. The grout lines are HUGE. Seems like the installer used unsanded grout. Big No-No. If grout lines are greater than 1/8" you must use sanded grout or the grout WILL crack. Grout may have also been applied too wet/ loose.


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(post #101201, reply #6 of 16)

Looks like a real hack job on the tile to me.  I'm no expert, but I did stay at a holiday in express last night.  I learned a lot on the John Bridge forum.  Several things.  Did they use thinset mortar or mastic under the tile?   With a sloped floor, if done properly, slopes from all sides into the drain.  12" square tiles dont follow the contour really well, so there's possibly parts of the tile that never made good contact with the thinset under it.  Mosaic is the way to go to follow the contour of the sloped floor.   I have slate tile in my shower with porcelain mosaic floor.  It looks great.  Only been a year so far, but I think I did a quality job after listening to the experts.  Even did my own shower pan.  For the weepholes, some of the tilers also suggested piling some of the plastic tile spacers around the weepholes to keep them clear.   As long as it's quality slate,  there should be no problems.  Keeping it clean can be difficult,  but I love the natural look.  Tear it all out and do it right. 

(post #101201, reply #7 of 16)

This sounds like a complete tear out and new shower.

Price would depend on materials and techniques. Price of tile, construction of membrane (sheet or hot mop), and extras such as new hardware, doors, and nitches.

But this is probably a $5-10K bid.



"I may be drunk, but you're crazy, and I'll be sober tomorrow." WC Fields, "Its a Gift" 1934

Regards, Scooter "I may be drunk, but you're crazy, and I'll be sober tomorrow." WC Fields, "Its a Gift" 1934

(post #101201, reply #8 of 16)

The whole floor is failing, water is standing under/in the tile, it squishes up when you walk on the tiles.

Hell not only am I not an expert but I'm not even an amature, and I didnt even stay at the Holiday Inn!

But this one line caught my attention. I watched a guy do a shower a couple years back and he was using MASTIC for the shower tiles.

About two months later the HO was complaining about the tiles being "squisshy",  the GC and I went over and popped a couple of the floor tiles up and the mastic was still nice and goo'eee. The tile installer had built it up as much as 1" thick in a few spots to get his slope.

Anyhow this required the whole tile job to be redone but the pan was still fine, matter of fact everything popped right off!


(post #101201, reply #10 of 16)

job's gonna be a freaking mess.

I can tell from here No Way did they take the time to run the waterproofing up and over that curb that the curved glass block is set on ...

and that means ... it's not waterproof.

also means ... gotta be waterproof under that glass block wall ... and there's a glass block wall in the way ... so that glass block wall has to go.

Unless ... someone else is comfy putting their name on a half-waterproofed shower.


plus ... can U tell how the bench is wrapped with waterproofing? Impossible unless U tear it apart ... I'd plan on bidding at the minumum stripping of all the tile up to the bench top.

and what's the deal with a premade pan and a concrete pan all together in the same shower? From what I can see ... unless it was a custom fabrication "premade pan" ... there's none that exist in that shape. So something goofy is going on there too.


That will is ... and will be a mess.

Only way I'd get involved is for a complete demo to the studs ... including that glass block wall ... and a complete rebuild.

and yes, slate is just fine for a shower. Just a pain in the [JOBSITE WORD] to keep clean. On top of everything else ... looks like lotsa shampoo residue on that seat ... they look to be sloppy house keepers. So even after U rebuild everything ... they're not gonna keep up with resealing the slate and grout ...


and in a coupla years all the mold and mildew will be your fault!


    Buck Construction

 Artistry In Carpentry

     Pittsburgh Pa

    Buck Construction

 Artistry In Carpentry

     Pittsburgh Pa

(post #101201, reply #11 of 16)

add an in-shower vent fan to the bid too ...

on an auto-humidity switch.

these people are not to be trusted!


    Buck Construction

 Artistry In Carpentry

     Pittsburgh Pa

    Buck Construction

 Artistry In Carpentry

     Pittsburgh Pa

(post #101201, reply #12 of 16)

Thanks for the responses.

I need the work, and these people need a solution. I told them I would not do a 'patch up" and that I would only be interested if they were willing to have this shower done right.

I have not agreed to take the job yet, told them that I would have to do some thinking and some research first.

The shower is built over a wood and joist floor, decent access below.

LJ and others: I am concerned as well about how the curb under the glass block may have/have not been waterproofed. I suspect that it was not done correctly.

I think the bench has to go. Total rebuild, if they want it back.

Frankie, your thoughts mirror my own. Clear down to the subfloor and see what we've got - start over. Looks like a candidate for a Ditra process, although I am more comfortable with mud beds and liners.

Jeff, I agree that there is something fishy going on here. Never have I seen a premade pan used in an area like this. I am hoping I can save the glass block, though. I don't think the owners are that careless judging from the rest of the house. The vent fan is a good idea.

Maybe I can turn lemons into lemonade? Maybe not.

Thanks, all.



"Citius, Altius, Fortius"


when you are up to yur knees in gators, make gatorade     

(post #101201, reply #13 of 16)

If someone wants a fixed price quote on this type of job I list a large number of assumptions, ie. floor decking is in usuable condition, show pan is in usuable condition, plumbing is correct, etc.  For each assumption there is the additional cost of correcting the problem.

This has been good for me since it forces a great deal of thinking on each area that might be problem and require extra work.  With enough assumptions it's also wiggling out of a true fixed price into what more closely resembles t&m.   It's good for the client since they can see the potential problems and how expensive it can be.

It sounds like the tile is poorly thought out and constructed.  If it's that bad from the outside it's probably worse inside under the skin.

(post #101201, reply #14 of 16)

maybe you'll get lucky and everything's water tight but they just used mastic?

My biggest concern ... how to remedy under that glass block if need be.


if ... the pan liner just stops short of a full wrap ... that curve leads me to think someone might have taken the easy way out ... as that'd be tough spot to get right ... how to fix it right without a full demo?

Like someone else said ... depending on the spray ... maybe ... just maybe ... it'd not scare me so much in person to wrap the liner up the side ... and call that a day?



on a side note ... I had a salesguy try to tell me I had to run the liner up the walls "a foot or two" ... I usually go higher than necessary ... 6 to 8 inches ... I always make sure we have more than enough ... I asked ... Why?

he started talking about "if the drain backs up blah blah blah ...

I just pointed to the curb and asked ...

"don't ya think it'll all run out here before it floods the walls 2ft up?"



    Buck Construction

 Artistry In Carpentry

     Pittsburgh Pa

    Buck Construction

 Artistry In Carpentry

     Pittsburgh Pa

(post #101201, reply #15 of 16)

Looks like a candidate for the Ditra process...

I'm currently building two custom showers in a vacation home.  Tile is slate.

I built a shower last year with the preformed slope for the pan, but prefer the mudbed as I've done with my current project.

But the point of my rambling is to extol the virtues of the Shluter Kerdi shower system! This was my first experience with it and I will NEVER use a PVC liner again! 

It's so damned easy to get nice crisp clean waterproof corners without all the gluing and fussing that goes with the PVC (I didn't even have to back cut the framing at the bottom like you sometimes have to do with the PVC).

Both the showers on my project have niches and one has a seat...waterproofing was a piece of cake and took less time.

Before installing the Kerdi, I filled all the joints in the tile backer and then applied a water proofing membrane called HydraFlex by Tec Industries (similar to RedGard).  It's formulated for shower construction and readily bonds with thinset, just like the Kerdi.

The HydraFlex was probably a little overkill, but I assure you, you will love working with the Kerdi system.


(post #101201, reply #16 of 16)

Without a doubt, rfollow Notchman and consider Kerdi.

Easy, fast, peace of mind.

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