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JDenise 11-03-2006 07:18 PM

Concrete Stamped Interior Bathroom Floor
In my new house I was determined to have a curbless shower in my master bath. I figured that one out ( we cut into the I joists and then reinforced the floor). Now I want to have stamped concrete floors of various colors in the shower and the rest of the bathroom. Is anyone familiar with how this can be done. Our concrete porch guy is scratching his head and thinks he needs at least 2 and a half inches of concrete in order to stamp it and is afraid it could crack easily. I think out of the box and believe it can be done. Anybody? Thanks

mudmixer 11-03-2006 09:00 PM

Stamped concrete is only for people with experience. If he has done it before, listen to him.

Only 2 1/2" is likely to crack, not matter what box you think out of, especially on a joist floor. You had the floor reinforced for strength. By cutting into the joists, you probably increased the joist deflection (which is what will cause the cracks) even though you have the strength. - There is a difference between strength and deflection. Something can be strong enough to hold the load, but it may deflect more because of the decreased floor support thickness.

Did an engineer come up with the suggested method of resupporting the floor?


inspectorD 11-04-2006 07:44 AM

You did what?
I am all for thinkin outside the box...however..
If you cut the I joists, without an voided any warranty of that product and compromised the integrity of the floor assembly. These systems do not work like a typical wood floor...they are an engineered truss system.
You also have a serious amount of weight on an non engineered floor.
I would love to see some pictures of this!!

As for the concrete floor idea, don't forget to do a really thorough job of flashing the entire room flooring area up the walls also, or you will end up with many moisture and decay issues.

bethany14 11-04-2006 08:15 AM

How thick is the poured concrete floor that is used for radiant floor heat? I can't imagine it would be much thicker than 2". How are those floors prepared for a concrete slab? Surely there is a way to preserve the solidity of such a small (shower dimensions?) area.
Wouldn't the creasemarks of the stamping application help avoid cracks?
"Contractors call these control joints. To the average homeowner these joints look like decorative lines. The principal is to make the slab thinner by cutting a line in the slab or by removing actual material so that the concrete doesn't crack randomly." --

Wouldn't suspending steel rebar in the slab reinforce it significantly?
Considering that the supporting floor members in question have already been reinforced, can they also be stabilized to minimize movements that might encourage cracking?
How much deflection are we talking about, on such a small area, indoors (not subjected to outdoor freezing).

On a negative note, sealing water out would be a maintenance issue, but certainly possible. This quote is worth noting, "The force of water cascading from the shower-head will quickly erode a finish layer of cement paste on the floor and reveal the rough texture of the fines (sand). Over time, the exposed layer of cement will trap dirt—whereas, the aforementioned finish materials (stone, tile, mosaic) will be able to withstand the relentless water erosion."

I love your idea JDenise, and I really want you to find a way to make it work. Here are some concrete sites I have come across in my researching: .htm

From what I've read, it's important that you have someone who has been trained specifically in stamping concrete. That may be why your avg concrete guy would scratch his head, or even scoff at your suggestion. You should consider taking a class yourself, or at the very least investing in some books on the topic.
I wish you the best of luck, and please keep us updated!

mudmixer 11-04-2006 09:59 AM

Concrete Stamped Interior Bathroom Floor
Bottom line is - get someone with experience and knowledge to look at your situation and make recomendations. It is not just a shower stall, but a room, so you cannot tolerate any cracks because of the moisture. "Wet rooms" are common in other countries where the floor and wall systems are not wood, so they have more rigidity.

The I joist reinforcement any be strong enough, but it may deflect too much for the floor to handle. What has been done is done and the reinforcement of an engineered system is not for amateurs. If you cut down the top to make room for the floor, you have drastically changed the properties of the floor.

Adding reinforcement to a thin slab is not effective to increase the ability to span, but it does hold the pieces together if it cracks.

Taking a class is not the thing to do if you can't find a contractor to to it and guarantee it. If there is a problem, you do not fix it, but you remove it. This room is not the place for a first job.


alterone 11-05-2006 05:00 PM

stick with tile or slate unless you are working on a slab...even one who works with concrete can promise "No Cracks" especially on a floor that will flex under that kind of lbs

JDenise 11-06-2006 09:15 PM

Following up---- The I joists were cut just in the area of the shower drain to asure a good slant to the drain. (about 3' x 5') My contractor will strongback the joists that were shaved and put an extra support beam underneath. I'm thinking of using 30 lb roofing felt on the subfloor and then use metal lath. The lath will give the first coat of Texture pave strength. The felt will protect the subfloor from the concretes moisture. The first layer will be very thin, about a quarter of an inch thick and is self leveling. Then 2 coats of thin finish will be used, about 1/8" each coat. Then a stain and sealer will finish the floor up. Does that make a little more sense to you guys.

gratefuleveryday4 02-03-2013 04:24 PM

why not
if you are preparing the shower pan with mud /wet bed, not really sure why you couldn't use stamped concrete as the top finish however just be sure the finish isn't smooth so it won't be slippery. Again the same would apply to the floor.
as long as the joists are secure and you prepare it with a sold base and use wet bed of a decent depth 3", much the same as the the old bathroom floors were made I don't think it would be an issue. I have renovated many houses with the original small black and white tile floors that are on wet bed of about 3" and it takes almost a nuclear warhead to remove it because it is so solid. I'm not a professional contractor but have done alot of renovations as a side line. Good luck to you with your project.

nealtw 02-03-2013 08:37 PM

grateful; Welcome to the site and it's great to see someone new trying to help but you want to keep an eye on the date of the last posting. This one is six years old and is probably a waiste of time.:)

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