# Curbless shower on concrete slab



## ksavar

Ok, this is my first post so bear with me. I'm still a little new to this whole internet as a means of having professional questions answered hah.

I'm a tile sub on a remodel in Houston, Texas, the client is having a bathroom remodeled. Part of the remodel is taking an existing coffin shower and creating a curb-less shower in it's place. The shower is going to have a 1/4" slope per foot spanning 60 inches. Here is where the question comes in. The sub doing the shower work is going to cut the slope out of the foundation, I've never seen this done on a on commercial site. Is this the normal way you would go about putting in a curb-less shower? It is by all means easier on me doing the tile work to have it done this way but the residential foundation is only 6 inches thick on a single story home like this. 

I just don't want an inspector to come through here and say it isn't up to code then the contractor or owner expect me to redo all the tile.

Any help is appreciated!


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## ScipioAfricanus

Sound like there is cause for your concern there.
Grinding the slab is done all the time or even demo'ing the slab is done but never the foundation wall without having a permitted plan to address the possible consequences of cutting into foundation.

I am not of much help but what the hell? I am edging in to 2000 posts.

Andy.


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## ksavar

ScipioAfricanus said:


> Sound like there is cause for your concern there.
> Grinding the slab is done all the time or even demo'ing the slab is done but never the foundation wall without having a permitted plan to address the possible consequences of cutting into foundation.
> 
> I am not of much help but what the hell? I am edging in to 2000 posts.
> 
> Andy.


Thank you for the quick reply! I'm nearly positive that if he ends up going this route he will get a permit. The contractor is someone I've known for a long time and have never see him not have proper permits on anything he puts his name too. He's a real by the book ass kicker. I suppose I should leave that up to him since I'm just the tile guy, but what's the harm in asking for a few other opinions?

Anywho, the shower actually won't be on the foundation wall, it will be about 3 feet from it on the highest point, and 8 feet on its deepest point. Anyone else done something like this?


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## tjbnwi

Cut the floor out and replace the concrete with the proper slope. This will allow the drain to be relocated/run properly.

You must waterproof the new "pan".

Don't cut the foundation.

Tom


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## CarpenterSFO

tjbnwi said:


> Cut the floor out and replace the concrete with the proper slope. This will allow the drain to be relocated/run properly.
> 
> You must waterproof the new "pan".
> 
> Don't cut the foundation.
> 
> Tom


Agreed. KSavar, when you say "foundation" in your original post, do you mean "slab" (rather than foundation wall or footing)?


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## ksavar

CarpenterSFO said:


> Agreed. KSavar, when you say "foundation" in your original post, do you mean "slab" (rather than foundation wall or footing)?


Forgive me, yes that is what I meant.


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## CarpenterSFO

ScipioAfricanus said:


> I am not of much help but what the hell? I am edging in to 2000 posts.
> Andy.


Way to go!


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## CarpenterSFO

ScipioAfricanus said:


> I am not of much help but what the hell? I am edging in to 2000 posts.
> 
> Andy.


Sounds like you're on the right track!


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## CarpenterSFO

ScipioAfricanus said:


> Sound like there is cause for your concern there.
> Grinding the slab is done all the time or even demo'ing the slab is done but never the foundation wall without having a permitted plan to address the possible consequences of cutting into foundation.
> 
> I am not of much help but what the hell? I am edging in to 2000 posts.
> 
> Andy.


Your post was very helpful!


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## CarpenterSFO

ksavar said:


> Forgive me, yes that is what I meant.


Do what Tom says, then.

- Bob


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## ksavar

I'm sorry for asking but I'm curious. What kind of problems could arise from cutting the slab instead of refilling it with the slope? Would it be a problem structurally or a code problem? I know code is different everywhere but you're welcome to chime in with hypotheses anyway.


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## tjbnwi

Do you know what style drain is being installed and its location relative to the existing? Most cureless showers are a single slope at ¼" in 12". If it is going to be a new lineal drain a replumb will be needed, might as well cut the floor. 

You can mortar a pre sloped pan or a dry pack over the existing. Problem I see with this will be the drain.

If it is a multi slope, the floor can be ground to meet the (assumed) center drain. It will still need to be ¼" in 12". 

No matter how it is done, make sure you waterproof the pan.

Tom


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## tjbnwi

No code issues either way that I know of as long as the pan is waterproof and passes a 24 hour test.

Tom


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## ksavar

tjbnwi said:


> Do you know what style drain is being installed and its location relative to the existing? Most cureless showers are a single slope at ¼" in 12". If it is going to be a new lineal drain a replumb will be needed, might as well cut the floor.
> 
> You can mortar a pre sloped pan or a dry pack over the existing. Problem I see with this will be the drain.
> 
> If it is a multi slope, the floor can be ground to meet the (assumed) center drain. It will still need to be ¼" in 12".
> 
> No matter how it is done, make sure you waterproof the pan.
> 
> Tom


Good point, it's going to have a linear trench drain at the wall of the shower under the fixture.


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## ScipioAfricanus

Make sure it isn't a post tension or pre-stressed slab before cutting into though.

Andy.


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## ksavar

ScipioAfricanus said:


> Make sure it isn't a post tension or pre-stressed slab before cutting into though.
> 
> Andy.


I doubt with a house this size (1500 sq ft max), and age is prestressed. Don't those have service holes usually?


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## tjbnwi

ksavar said:


> I doubt with a house this size (1500 sq ft max), and age is prestressed. Don't those have service holes usually?


They have some seriously tensioned cables in them. I've seen one cut that rolled back right through the concrete. Lucky no one got killed.

Tom


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## ScipioAfricanus

Usually there is an stamp embossed into the garage slab if it is a PT slab.

Andy.


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## ArtisanRemod

Forgive me if this is OT, but why would a slab have tensioned cables in it$ I'm not familiar with that.


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## ksavar

ArtisanRemod said:


> Forgive me if this is OT, but why would a slab have tensioned cables in it$ I'm not familiar with that.


I've never really seen it done in residential construction, although calling a buddy he says that it's actually fairly common. With Houston having shifting clay soil, putting tension on the concrete will help prevent it from cracking.

I'm not really well educated on foundations, but it is very interesting.


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