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cement board as shower pan

48737 Views 121 Replies 22 Participants Last post by  Mike Finley
I am new to this forum and new to the tile trade 39 years ago. I know that this is not the place for advertising. I have figured out a way to use cement board as the shower pan. I will be attending the "Total Solutions" conference in San Antonio in Sept. given by the NCTA and after that I will be using this sight to PURCHASE advertising space and with that display the website link so anyone can check it out.

My question is :

I wanted to know if anyone has seen a post that discusses the use of CBU INSIDE the shower AS the pan.
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I am new to this forum and new to the tile trade 39 years ago. I know that this is not the place for advertising. I have figured out a way to use cement board as the shower pan. I will be attending the "Total Solutions" conference in San Antonio in Sept. given by the NCTA and after that I will be using this sight to PURCHASE advertising space and with that display the website link so anyone can check it out.

My question is :

I wanted to know if anyone has seen a post that discusses the use of CBU INSIDE the shower AS the pan.
Are you talking about using CBU for the pre slope?

If so, that's not a new idea.
I need to stay fuzzy on this until after the Total Solutions conference on Sept. 17-18. I'm sorry. I have a non-disclosure agreement with a couple of entities and I will be able to give the details after that. I am a professional of 39 years in the trade a can appreciate your frustration when someone says he has a better mousetrap and then won't show it. No we don't cut the board into pie shapes, PermaBase and Durock are the two boards that will work. A vinyl liner gets clamped into the clamping ring of a standard two part drain ( oatey , Sioux Chief). Liquid water proofing like Mapei Aqua defense or LATICRETE 9235, hydro ban are used at different intervals to actually "waterproof" the cement board, fiber mesh is used to "tape" all corners and wall to floor, verticle wall corners and threshold. AND a SECRET as to how the board is pitched with FULL support under. Again I'm sorry for the need to be so vague at this time. I will try the JohnBridge site and continue to post on this site after I am legally able to. Please be patient.
I doubt it's a secret.

Again, using sloped backers as a pre-slope is no new thing. My only curiosity is the mortar bed on top of it. That's a hard one to make idiot proof for a DIY-er but there are tricks to that as well (screed guides from fins, pipes, etc.)

I wasn't aware the home centers were selling mesh based anti-fracture/waterproofing membranes like 9235. Maybe this is something new in other markets but certainly not mine.
Again I can take all of these responses as valid concerns. Not all people ( Harry Homeowner ) would try
to do this type of work anyway. The trade pro's will be the guys that I will need to convince and I KNOW
that this will be a large task. As for 9235 being a mesh based anti/fracture, it's a liquid waterproofer.
Brushes or rolls on. In our market, outside of Chicago, fabric is available at the Home Depots and Menards
9235 is a TWO part system comprised of the liquid AND the mesh/fabric.
I framed this soak tub, wrapped it in bending ply.... wire mesh... mortar... then lined and wrapped it in 9235 before installing the tile. Leaked like a sieve the first time and had to be re-lined. :censored::furious::censored::furious:

9235 is rated for fountains but I'll never use it inside again. (and putting it in the hands of a rookie is almost criminal.)

It was one of the biggest PITA projects I've ever gone through. 9235 used to be all I used for steam showers--I'll never go back after using Kerdi.

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You shouldn't post pictures of work like that, it's going to hurt your reputation. :whistling

Um, but seriously, that's like a work of art. Very nice, very, very impressive! :thumbsup:
Thanks Mike.

It turned out very nice... but it hurts to think back on how it went together. I pushed the envelope and got burned twice on that job... and both were directly related to the waterproofing. NEVER AGAIN WILL I DEAL WITH THAT BLACK SH**...

It's one of those projects that are always in the back of my head---"God I hope I don't get a call about THAT one again..."
...and it's acceptable by the TCNA ...
That's the gold standard when it comes to tile methods. Are you planning to submit your "system" to them? Just curious.

Is your method going to come in a kit...or will you just be selling the information on how it's done?

I realize you're all cloak and dagger at this point... but I'm still not hearing anything revolutionary.

Pre-slope with backers
Vinyl liner over that to a clamping drain
Some kind of base over that for the floor tile
Backers to the wall with a liquid & mesh waterproofer

I'm curious about the cost as well. A mini unit of 9235 is still a pricey bugger (plus the mesh comes folded and creased which is a huge PITA). If I recall, the mini unit only does 30 sq ft. Unless there's a unit somewhere that just comes with the 6" roll of mesh. Even the liquid only hydro ban is about $100 a gallon.

As for using the liquid only products with a mesh... that sounds like using a product in a different way than it was intended. Hydroban was specifically designed to be used WITHOUT a mesh.
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There's very little left here to debate until you're willing to roll out your magic method. Saying "it's a secret" is getting old.

You can trot out photos all day long but who's to say that mortar bed was installed correctly? The fact that it was cracking through the grout tells me it wasn't. Some guys can't pour piss out of a boot if the directions are on the heal--but that doesn't mean the method they were "attempting" is inherently bad.

A pre-slope, vinyl liner, and mortar bed shower system is still a good method if done correctly by an experienced installer. Is it the most efficient, longest lasting technology? No, not anymore. Yes, Kerdi is favored among many professionals because it's clean, labor efficient, and about the most waterproof AND vapor proof product on the market. There are also other systems available which compete with it where pans are concerned: Wedi and Tile-Redi for example.

If I recall, one of your motivations for developing your method is to make it more DIY friendly. I'll not debate the efficacy of that motivation--but I will say that as professionals we've humored you up to his point. If you'll read the TOS of this forum, you'll find it was never intended to be a mining ground for those wanting to bounce ideas for new products or services. For those of us who participate in this forum, you're not solving any problem. We already have alternate technologies to a vinyl pan shower that are better than having to get elbow deep in black goo (or green, as the case may be). :laughing:

Before you launch into a passionate defense, let me make a few things clear to you. You might be thinking all the eye rolling is mere ego or protectionism of our trade and livelihood. But anyone who's been around the block in construction can tell you that any system can be f-ed up by a non-professional--and more often than not is f-ed up by wanna-be professionals.

When it comes to building a shower, there will always be factors that no amount of streamlining will remove from the equation. Things like plumbing and framing and the knowledge and skill which comes only with repetition.

I don't mean to trash every homeowner who's ever drove a nail or set a piece of tile in their own house. But I've worked in enough houses and torn out enough things built by well-meaning HO hands to know it's usually the next owner who pays the price for the sloppy work. A weakness or flaw in installation can many times take YEARS to make itself known and can usually only be fixed by completely tearing out and starting over.

Speaking only for myself, I'm not concerned in the least about a new DIY technique for tiling showers. There will always be those who want to save a little money or try tiling just because they enjoy the challenge. Those are not the folks who would hire a professional in the first place--regardless of the existence of your DIY method.

At the end of the day, I don't doubt the possibilty that by combining existing waterproofing liquids and backers you can come up with something watertight enough for a shower. The question then is: Why would anyone use it as an alternative to the more mainstream methods and technologies available? Just because it's cheaper? I doubt very much that it is if you include labor cost in the equation.

Best of luck to you... maybe we'll see you at Coverings 2010. :thumbsup:
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... I don't want to try and convince my customer that "Dura-Wetshield" ....

Say, that's pretty catchy... You need to trademark that. :laughing:
St Damian's beard! PLEASE don't bring up pre-slope here :sad:

Pre-slope, Pre-slope, Pre-slope...

Yes, by MY product is well on it's way! Can't say anything right now either. It's ancient Chinese secret. Jimmy Wonton is testing for me :chinese:
Sorry for yoo, round eye.... Me cyber-squatting on
Hello Boys. He's back. For your information my idea was well received at the
Total Solutions Conference in Sept. I DID AND ADMIT, have some blind spots in the technique that I was called on.I am adjusting my idea to include the recommendations. I see that this forum is NOT the place to open up a new idea. You are right that I was trying to get a feel for the possible acceptance of something new but again I see most of the guys that post here are set on
a certain product and that's fine. This forum seems to do less for helping someone and more about just a few guys using it like a myspace page to tell the world what they know.I will read the negative comments that a few of you will inevitably post , let you laugh about it and confirm what I said that this forum has seemed to become.

I will do fine,
I think you've mistaken the back and forth banter, most of it regarding threads you had no part of, as some inside joke at your expense. I can only speak for myself in saying my comments weren't directed at or against you in any way.

Yes, there are some very opinionated craftsmen around here, as there are on any jobsite. If you'll recall our previous discussion when you first started this thread, my comments were directed at the efficacy of your idea--and not a personal attack on you.

Any entrepreneur, inventor, visionary---must be prepared to have their ideas scrutinized when they don't conform to the status quo. If your idea has merit, you don't do it justice by shrinking away from that scrutiny.

At the end of the day, your ideas will either stand on their own, or they won't. But gathering up your toys and going home doesn't benefit you, or those who might be lurking in this thread--curious to see if your method may be a better mousetrap.
Ready? The revelation.... A piece of 1/2" cement board is thin-set and nailed to the wood sub floor to help to minimize deflection. The way I pitch the cement board to the drain is by using 4"wide x 5/16"thick cement board edge strips on the perimeter of the pan dimension making a frame. They are secured with medium bed thin-set. Another piece of 1/4" or 5/16" cement board is then cut the full floor size of the shower pan are (example 48" x 32") A full spread of medium bed thin set is troweled over the edge strips and the floor area and this top cement board is set into it. By stepping from the drain to the walls and all around the base you will "Form" a bowl with a pitch to the drain of 1/4" per foot as required by plumbing code.Try it yourself and you will see it works. The cement board is water proofed with a liquid topical waterproofer at the corners, curb, and the whole top of the top cement board (the part to be tiled) Fiber tape is used in the corners and "Taped" also with water proofer. The blind spot I metioned was how I tied it into the drain assembly. That has been worked out. I use smaller strips of fiber and they too get waterproofing on them. 2 coats as recommended by the manufacturer.There is no vinyl liner or two part sheet membrane used.Nothing to trap water between. The "liner if you will is just under the tile and that layer is what is pitched to the drain.There is only one cement board manufacturer's product that will work with this and they have supported me from the beginning ( about 6 months) also I recommend only one waterproofing product to be used. They too have supported me. I was not shot down at the conference, on the contrary, the comments I heard more than once was " new and inventive". I have a large tile supplier in the Chicagoland area allowing me to run workshops to get the idea out. So, Bring on the questions.

I realized you guys were entitled at least this much information
I suspected this was your method, as this is typically how I do my pre-slopes--althought I use rips of stud lumber to frame the perimeter, and rip wedges from the perimeter to the drain to create a consistent slope. I've also used partially set screws to support the sloped backer until the mortar dries.

Your comment on installing the first layer of cement board to minimize deflection is not exactly accurate. There isn't any tile backer material that adds to the structural stability of a floor system.

Are you using a standard clamping drain? Are you tiling directly over the weep holes?
....Although since I tile this top layer of cement board I can't see water getting under the tile and fighting the thin set used to install the tile and then making it to the drain...
It's a surface level water proofing, I understand that. But it's inaccurate to say water won't beat the grout and thinset...those materials aren't waterproof.
Chris , this method will work AS A PRE-SLOPE. Don't use any liquid water proofer. Just use cement board as a perimeter and another piece set in medium bed with the drain hole cut out.Put your liner in and do you deck mud the same day. That's what I was fishing for on the other thread when I posted "Who sets the liner in your area". I was going to show that my method could be done easily by the plumbers BEFORE they do the liner. There I said it again Pre-Slope
As I said, this is how I do my pre-slopes....although I do a slope of 1/4" per foot... it sounds like you're getting less than that.
My point was that the water they MAY go into the grout and under the tile
would not have a clear path. In a mud base you know the mud does not adhere to the liner.Water will go under the solid base and get to the weep holes ( maybe) I'm saying that since I am using thinset to install the tile layer
the water would be slowed and not travel freely to the weep holes , even though I leave them free. It is my opinion that the small amount of water that actually permeates the tile and grout will evaporate out before building up enough to cause mold or smell. The other thread I posted about Who installs... Many guys said that they have NEVER tore out a shower and saw a pre-slope. In those showers, again they may not of been leaking, there could no way be the same amount of water trapped in my design as those.
How is the amount of water that gets through the grout any different with your method than it is with any other?
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