Shower curb - concrete or cement board?

[Tommy2000GT]

My contractor wants to make the shower curb with cement board.

But from what I've seen, most shower curbs are made with metal wire and poured concrete.

He insists cement board is the current way of making it.

 

[herm0016]

you can use cement board over wood, then it gets painted or covered with a water tight membrane.

 

[Greenman]

It's never poured concrete. It's often wood frame with wire mesh and mortar over it. Wonder board is fine as long as it's properly installed. The shower membrane should be continuous all the way over the curb (I like to run it a few inches out onto the floor). After the pan has been tested, skin the curb with wonderboard but don't nail it below the lever of the drain. I recommend capping it with red guard, though it's not strictly necessary.

Note that testing the pan by filling it 1/2" over the top of the drain is critical. Fill it, let it sit for 24 hours, then inspect for leaks. The tile installer also has to be very careful not to puncture the membrane while working in the shower.

 

[Tommy2000GT]

It's never poured concrete. It's often wood frame with wire mesh and mortar over it. Wonder board is fine as long as it's properly installed. The shower membrane should be continuous all the way over the curb (I like to run it a few inches out onto the floor). After the pan has been tested, skin the curb with wonderboard but don't nail it below the lever of the drain. I recommend capping it with red guard, though it's not strictly necessary.

Note that testing the pan by filling it 1/2" over the top of the drain is critical. Fill it, let it sit for 24 hours, then inspect for leaks. The tile installer also has to be very careful not to puncture the membrane while working in the shower.

Yes I meant mortar and he finished it today with mortar and wire mesh which I requested him to do.

Should I have him paint the shower pan, mortar curb, and cement board walls with Redgard for extra waterproofing?

 

[Greenman]

Yes I meant mortar and he finished it today with mortar and wire mesh which I requested him to do.

Should I have him paint the shower pan, mortar curb, and cement board walls with Redgard for extra waterproofing?

No. Assuming the pan and curb were properly installed there is no reason to coat it with redgaurd.

 

[Subyman]

Greenman, most people in my area request cultured marble pans. I've never personally installed or had poured shower pan installed in a house. For standard sized (32,48,60in) showers, the cultured marble pans are extremely quick to install. In your experience, is the labor/tile/misc cost of the poured shower floors about the same as the install/material cost of the cultured marble pans? I'd think labor may make the poured floors about the same cost. This is obviously only for standard sized, anything custom and the poured floors are likely the best way to go.

 

[Greenman]

Greenman, most people in my area request cultured marble pans. I've never personally installed or had poured shower pan installed in a house. For standard sized (32,48,60in) showers, the cultured marble pans are extremely quick to install. In your experience, is the labor/tile/misc cost of the poured shower floors about the same as the install/material cost of the cultured marble pans? I'd think labor may make the poured floors about the same cost. This is obviously only for standard sized, anything custom and the poured floors are likely the best way to go.

It's never a poured pan. They are always framed out of wood, waterproofed, then covered with mortar. Cost wise, I'm sure they're more than a cultured marble pan. Most of my projects are higher end, and a custom tile pan is standard. The process is like anything else in construction, easy to do and easy to screw up. Testing is critical, I always fill the pan with water for 24 hours before the mortar goes in.

My favorite pan is called Floorstone. They're a basic white shower pan that's inexpensive, easy to care for, and should easily last for 30 years, 40 or 50 if you actually take care of it.

 

[Humpy]

It's never a poured pan. They are always framed out of wood, waterproofed, then covered with mortar.

You may be unaware of the way things are done in other parts of the country/world.

i.e. over a concrete subfloor a shower curb, or shower walls/ceiling/floor, is often constructed of cast in place concrete, or stacked brick, or left out entirely. It makes little sense to trap a few pieces of wood inside what is otherwise a structure entirely constructed out of masonry materials.

Similarly, the decades old method of water proofing under the finished tile substrate/backing material or masonry pan with rubber or lead or hot tar works okay, in standard configurations, if every step is carefully taken. But those methods are pretty limiting and not ideal overall. A waterproofing membrane usually functions best if it is the finished surface or directly under the finished surface.

 

[Greenman]

You may be unaware of the way things are done in other parts of the country/world.

i.e. over a concrete subfloor a shower curb, or shower walls/ceiling/floor, is often constructed of cast in place concrete, or stacked brick, or left out entirely. It makes little sense to trap a few pieces of wood inside what is otherwise a structure entirely constructed out of masonry materials.

Similarly, the decades old method of water proofing under the finished tile substrate/backing material or masonry pan with rubber or lead or hot tar works okay, in standard configurations, if every step is carefully taken. But those methods are pretty limiting and not ideal overall. A waterproofing membrane usually functions best if it is the finished surface or directly under the finished surface.

Learn something new every day.
You're right, I wasn't aware that anyone in the US poured a shower pan. I've been remodeling homes for 40 years and I've never seen a cast in place pan. Though we don't have all that many slab floors either.
How does it work? Do they use a mold or dry pack the concrete and shape it by hand? A youtube link would be awesome if you have one handy, I'd very much like to see the process.

Hot tar waterproofing works very well. I've seen quite a few that lasted for over 50 years. No one around here does it anymore though, way to slow and messy. We all use the PVC membrane. I've had very good results with it, but I always make the tile setter float the pan first to protect it.

Edit: I've been thinking about how this would work, and I'm not getting it. Even with poured concrete there has to be a liner, and that liner needs to extend over the curb. So it would have to be a sub pour, a liner, then a surface pour? I really want to know how this works.

 

[Humpy]

Learn something new every day.
You're right, I wasn't aware that anyone in the US poured a shower pan. I've been remodeling homes for 40 years and I've never seen a cast in place pan. Though we don't have all that many slab floors either.
How does it work? Do they use a mold or dry pack the concrete and shape it by hand? A youtube link would be awesome if you have one handy, I'd very much like to see the process.

Hot tar waterproofing works very well. I've seen quite a few that lasted for over 50 years. No one around here does it anymore though, way to slow and messy. We all use the PVC membrane. I've had very good results with it, but I always make the tile setter float the pan first to protect it.

I'm not sure about a video. It often starts just by leaving a ~ 2" depression in the slab in the shower location. Sometimes we'd build upper floors with hollow-core concrete planks where there couldn't be a depression. If the curb was simple and could be easily formed up we would just mix up concrete. Some abstract shaped curbs were easier done out of brick, than lathed and plastered as usual. Curbless showers were fairly common and there is no where to terminate a pvc liner. The slope was done out of dry pack or small aggregate concrete with plasticizer. Then water proof everything with Hydro-Ban before finished surface goes up.

Keep in mind this is talking about the occasional silly complex shower. Indoor steam rooms that opened to heated outdoor showers. "Wet rooms" where the whole thing was a shower/tub/steam room combination. Showers that resemble an adobe kiva and every surface was curved. Shit that architects dream up for rich people to show their friends but suck to actually take a shower in.

When it was up to me and/or the customer had more brains than money, I liked to put in a simple one piece cast iron shower base, install whatever wall surface was wanted, and be done with it.

Edit: The key to all of this is abandoning the use of a traditional liner and relying on a liquid rubber membrane, which many are hesitant to do.

 

[Humpy]

Greenman, after re-reading, I apologize for posting as a know-it-all, as I tend to do. You clearly have a wealth of construction knowledge and have contributed far more to the forum than i ever will.

I tend to get a bit triggered when I see it stated that there is only one way to do something when I know there a bunch of ways to do things correctly. This is of course often different than making a business decision to stick with known processes with known outcomes and profitability.

 

[paperfist]

You guys ever do a full custom tub? I always wanted to try that but I just know it'll leak.

 

[Greenman]

Greenman, after re-reading, I apologize for posting as a know-it-all, as I tend to do. You clearly have a wealth of construction knowledge and have contributed far more to the forum than i ever will.

I tend to get a bit triggered when I see it stated that there is only one way to do something when I know there a bunch of ways to do things correctly. This is of course often different than making a business decision to stick with known processes with known outcomes and profitability.

No worries my friend, I took it as educational information.
I do tend to speak in absolutes, and often come across as pretty arrogant, but that's only because I really am pretty arrogant, much as I hate to admit it.

 

[Greenman]

You guys ever do a full custom tub? I always wanted to try that but I just know it'll leak.

Did one about 40 years back. It was an enormous pain in the ass and I doubt it lasted very long. I was an employee and had no real clear idea of what I was doing, and not a lot of direction or information about the process. I just framed it and water proofed it, some other poor soul tiled it.

 

[Scarpozzi]

I've done one in concrete before that was directly on a slab. The worst part is sealing the concrete prior to tiling it and waiting for the concrete to cure....then the sealant to cure....and in my case, I had to run plumbing in the concrete due to structural limitations on that job. It ended up working out great, but was a pain and took a few weeks to complete due to cure times.

 

[paperfist]

I've done one in concrete before that was directly on a slab. The worst part is sealing the concrete prior to tiling it and waiting for the concrete to cure....then the sealant to cure....and in my case, I had to run plumbing in the concrete due to structural limitations on that job. It ended up working out great, but was a pain and took a few weeks to complete due to cure times.

Did one about 40 years back. It was an enormous pain in the ass and I doubt it lasted very long. I was an employee and had no real clear idea of what I was doing, and not a lot of direction or information about the process. I just framed it and water proofed it, some other poor soul tiled it.

Thanks for the info guys. I guess I won't attempt it

I want to put a tub on my 2nd floor and it has those crazy attic type angles that a custom tub would be great for. Originally the thought was to put in a skylight to increase head room so a standard tub wouldn't be a problem, but everyone I talk to says they are great for a few years and then leak like mad.