trench drain for shower?

dallasmodernFebruary 22, 2008

Just curious if anyone has done this before. We are doing a bathroom with a large shower, no threshold or curb, 24"x24" floor tiles throughout. To accomplish this, the floor will slope toward the wet wall with the shower trim, and at the base of the wall will be a trench drain running its full length.

The challenge seems to be finding the right drain hardware. We've found a variety of options, but aren't sure which is best for the application. The tricky part is how the membrane attaches to the drain assembly.

This (ACO Membrane Drain) is what our plumber recommends, since the drain channel is made to clamp in the membrane across the full length of the channel. But, it is more than double the width of what we want and it quite expensive$$$.

The Stormtech 38AG is an attractive option, but the company is in Australia, and we're not sure about the the membrane connection detail which is essentially both the membrane and a small pipe from the trench drain feeding into to a larger drain pipe sitting in a rebate. Thoughts on this method?

We like this drain (ACO MiniKlassik), but apparently no way to attach the membrane, unless we could install it in the same way as the Stormtech above. Thoughts?

How would you make this work?

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The Stormtech 38AG is a very interesting product. Thanks for bringing it to everyone's attention.

You might look at the Schluter web site for ideas. It seems like the Stormtech would work with the Schluter-Kerdi-DRAIN system. The membrane attaches to the DRAIN system, and the drainage pipe from the Stormtech would be inserted into the drain pipe. A problem would be how to get this to work against a wall, as there is not enough room for the Schluter-Kerdi-DRAIN.

My home which is now being constructed is also suppose to have a french drain in the shower. I think the architect was planning on leaving it open, but the Stormtech would provide a much more finished look. I will consult with my contractor to see what his plans are for the french drain and post any new info. Whatever method he is planning on using to attach the membrane to the drain should be sufficient to use the Stormtech.

Have you found a distributor willing to ship the Stormtech product to the USA? If so, please post their contact info.


Here is a link that might be useful: Schluter-Kerdi-DRAIN

    Bookmark   February 22, 2008 at 5:21AM
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The solution seems to be to use a clamping drain.

The company Zurn carries both sectioned trench drain assemblies, and clamping drains. The membrane runs under the trench drain and clamps to the clamping drain.

I incorrectly named this a french drain in my previous post, but it is more correctly known as a trench drain. Web search for "clamping trench drains" for more suppliers.

Also see the link to an interesting write up on installing trench drains.

Here is a link that might be useful: Installing trench drains

    Bookmark   February 22, 2008 at 6:23AM
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You will probably find that most trench drains are quite expensive. The smaller ones are typically installed in commercial applications like high school and health club showers. This means they should be well made but expensive.

    Bookmark   February 22, 2008 at 12:06PM
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Those are cool, and I seem to remember seeing one in a bathroom book, but I'd just want to insert a note of caution re using 24" tiles in a wet area. Grout is a great traction source, hence the usual recommendation to use smaller tiles on the floor. Unless your tiles have a really good COF even when wet (and I mean *really* good, because you won't be able to have a mat down in a wet area), or if you're planning to put a wood grate over the wet area, I would suggest considering the idea of using a smaller coordinated tile on the specific wet area. No one will think you less modern :), in fact they'll see that you know that form *follows* function :)

    Bookmark   February 22, 2008 at 4:11PM
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Thanks for all the comments.

Modernhouse: Regarding the solution, we were thinking along the same lines. Our plumber has confirmed that he can install the ACO MiniKlassic using the same technique suggested in these StormTech drawings, much like the clamping drains you suggest.

Regarding a US distributor for Stormtech, no I haven't found one, but they do ship to the US. In fact there is another guy here in Dallas currently installing a 4 foot. Apparently it cost $275+$175 shipping (details here).

Flyleft: I guess Gropius et al would kick us out of their club. We're willing to put function after form in this case. The thought of an abrupt change from 24x24 to 6x6 or some such is just too painful aesthetically. I guess we'll get to see if 24x24 is going to be painful physically!

    Bookmark   February 24, 2008 at 9:10PM
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dallasmodern, I'm as modern in tastes as the next Dwell charter subscriber :), but I will tell you that it can actually look wonderful to use smaller tiles next to larger tiles of the exact same kind. Not over-ornamental or anything, if that's what you're worried about...I'm not giving up on your safety yet :)

    Bookmark   February 24, 2008 at 10:03PM
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I hear you, and appreciate your concern, but we're not feeling it. You'll be happy to know that we have specified the thinnest possible grout lines.

Shower glass doesn't have to be tempered, does it? :)

    Bookmark   February 24, 2008 at 11:15PM
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You are probably going to have to cover your 24 inch tiles with an ugly rubber bathmat for safety.

    Bookmark   February 25, 2008 at 11:05AM
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ooooo.k., then, don't come crying to me when you break your toe or your coccyx :)

    Bookmark   February 25, 2008 at 12:30PM
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I can tell you from experience that even 6 inch tiles can be too big for a shower floor. That's what my mother had put into her small shower, and it is very slippery when wet. She now has a rubber mat down.

    Bookmark   February 25, 2008 at 1:15PM
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Well, we'll know if it is too slippery soon enough. The finish is not too smooth and certainly not glossy. The sample we have provides pretty good traction when wet. Of course with lots of soap any hard surface is going to get slick.

I wish I could tell you the manufacturer of the tile, but or local dealer shows it using an internal identifier. Here are a couple shots of the same tile (different color)

Not sure if you can see the texture of the finish, but it is matte and somewhat stone like...

    Bookmark   February 25, 2008 at 8:53PM
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If it is any interest to you, I am looking at tile from Altas Concorde. They have a Cementi line of floor tile that looks very similar to your tile. It definitely has some traction, like a cement tile.

Here is a link that might be useful: Atlas Concorde

    Bookmark   February 25, 2008 at 10:18PM
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modernhouse, that Cementi is beautiful tile--one of our finalists. Which color are you using?

    Bookmark   February 26, 2008 at 12:14PM
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Regarding ordering the Stormtech drain system, I emailed the company and they replied that they do indeed ship to the United States. The company takes international payments with a credit card to handle the currency conversion. They said air freight generally takes 5-6 days.

flyleft - The Atlas Concorde tile is also on my short list, but I have not decided on color yet.

    Bookmark   February 27, 2008 at 12:47PM
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flyleft: I am not sure that what we have specified is the Cementi, but from the photos, it would appear to be similar if not the same. We are doing sort of a light cream on the floors and walls.

Our tile source (Horizon Tile) had this particular tile in the light cream, dark cream, and charcoal shown in the photos I posted previously.

Floors are 24x24, walls 12x24. Where the vanity is we will have a "feature" wall that is furred out 4" and will have a small glass tile in 1x4 (or there abouts...I can't remember just now). In one bathroom it is orange, the other blue. I wish I had photos, it is really pretty. It has a slightly wavy glossly finish, but the base color has a nice range of tonality and some small gold flecks. Haven't been able to find any photos online and I don't have a sample to photograph.

    Bookmark   February 28, 2008 at 4:56PM
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The tile in those pictures looks a little more like Marte's Nero Acapulco than the Cementi.

If it is the Marte line, they have three finishes for their tile. The polished is called "levigato" or something like that. It would not be suitable (my opinion) in a shower, I think it'd be a little too slick when wet.

They have a "naturale", which is somewhat non-slip and I think it would work well in a wet area.

They have a "bocciordato" (sp?) that's also referred to as a hammer finish or a hammermill finish, I forget. It's rougher and it great for traction, but the texture might get muddled when grouting and it might be a scum trap in a shower.

Just an uneducated guess, which seems to be my specialty these days.


    Bookmark   February 28, 2008 at 6:54PM
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Oh! Mongoct, right you are. I did a Google search for "Marte Nero" and found another photo of the same showroom with the tile identified as: Marte Nero Acapulco 12x24x3/8 Matte. The question is what is "matte"?

flyleft and modernhouse: my apologies for jumping in above, I thought that flyleft was addressing me, as on another site my screen name is modernhousedallas, and so "modernhouse" confused me. sorry!

    Bookmark   February 29, 2008 at 11:57PM
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You throw enough darts at the dart board and eventually you hit the bullseye!

I'd guess that the "matte" is the "naturale".


    Bookmark   March 1, 2008 at 11:44AM
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You're too modest. I suspect that bullseye was 99% knowledge and 1% good fortune.

    Bookmark   March 1, 2008 at 9:49PM
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And you'd be right, dallas. There's very little that mongo doesn't know.

    Bookmark   March 1, 2008 at 11:12PM
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I'm in process of ordering same grate. I'm curious, have you gotten yours yet? Will we be up to code? Any issues plumbing the grate. Should the grate's trough slope when installing or is it pre-sloped when placed level? Hard to ask all the questions I have via email. Quite frustrating actually because I got one question responded to initially, and now that I'm in a rush, I asked 2 more questions to close the deal with no response in 3 days. Hope you read this. Am I better off setting the alarm and making that Int'l call to Australia

    Bookmark   March 11, 2008 at 5:33PM
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Hope this is helpful and not too late. Check out the PDF below that illustrates methods of installing trench drains in curbless showers.

Here is a link that might be useful: NCSU Design School's PDF - Accessible Living

    Bookmark   March 13, 2008 at 9:47PM
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Sorry, have been slammed at work and by life in general of late... Reanime, we have it, and the plumbers installed it this week. They had a hell of a time doing it I think, as they had never done one before and it turned out to be a bit of a puzzle I think. They ended up installing it very much like the drawings on the Stormtech site show (the link I added in the previous post seem dead, so I will post it again below). In essence, they built out a box below the level of the shower floor, set a drain at the botom of that. Shower liner covers all and feeds into weep holes in lower drain assembly... I just hope the got the level right so when the tile comes in we have a nice clean junction. Also, I have been so busy that I have only had a chance to get a quick look at the installation in poor light, and the protective plastic is still covering the stainless parts, so it is hard to know what it will really look like finished.

Regarding the sloping, ACO makes both non-sloped and intenally sloped drains, so installation would depend on which you go with. We have non-sloped, so there this was accounted for in installation.

The drain arrived on a pallete, quite heavy. Each 3 ft section probably weighs 20+ lbs. The polyester-polymer concrete that makes up the channel base is heavy and HARD. It also looked much rougher than in the pics on the website, but of course this part of the drain is never seen after installation. Our plumber was freaking out about cutting it, so we ended up taking it to a water jet place to have it cut ( They did a subperb job. Extremely clean and precise. Our plumber's guys broke a bunch of regular drill bits trying to drill out the drain hole, then they decided to go and buy the concrete or diamond bit as the installation specs called for in the first place.

Anyway, to summarize: first impression made me a bit apprehensive as it was much more industrial feeling and less refined that I expected. I think this was largely based on the weight and appearance of the polymer concrete channel base. Reserving judgment until the plastic is off and the tile is in. If I had it to do ove again, I might do the Stormtech. I would certainly like to see them side-by-side. I snapped some pics of the installation as it is now, and will post them in a follow up message.

Tegarding code, I would recommend that you speak to your plumber and local inspector.

Here is a link that might be useful: stormtech installation- timber floor

    Bookmark   March 14, 2008 at 11:25PM
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Forgot to add: drain assembly was a clamping drain, just as Modernhouse suggested.

    Bookmark   March 14, 2008 at 11:56PM
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Sorry, but I do not have the Stormtech. We decided to eliminate the trench drain because the contractor had not accounted for it in the framing. Originally, I was going to have the tub drain onto the floor, then into the trench drain. The contractor decided to drain the tub directly so we don't really need the trench any more. I never looked into the product enough to see if it was pre-sloped.

As dallasmodern says, code issues are best answered locally. My understanding is that the stormtech product is not code approved in the US yet, but building the trench drain as dallasmodern is, with the grate assembly on top of the membrane, should ease inspection approval since you are not depending on the stormtech to be water-proof.

Good Luck...

    Bookmark   March 15, 2008 at 6:16PM
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My master bath project is at least a year away. I would love to use the trench drain system because I am going for that uniform floor look that you see in all the italian bathrooms.

I wonder if schluter will come out with this system. their products are well engineered and easy to install by DIYers.

    Bookmark   March 15, 2008 at 7:22PM
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I was interested in this idea in new construction using the concrete slab as the shower floor- heard that concrete wasn't a durable surface. Any thoughts?

    Bookmark   September 22, 2008 at 6:45AM
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We are installing a channel drain from Quick Drain USA tomorrow. The drain is fantastic! I have never installed one before and put it through it's test at my home.

The drain was able to handle 22 GPM (Gallons per minute) or 83.3 Litres per minute and this was the max I could get with my homes system and my neighbors hose.

I flood tested the drain and it's attached Nobel Seal Fabric over night and the drain stood firm - no leaks at all!

Tomorrow we change out the old 1 1/2" copper bath tub line to a new 2" solid cast iron line. We have access from the suite below and will include repairing their bathroom's ceiling and repainting into my clients expenses.

This was very neighborly and without this favour from below the shower renovation would not happen. As luck would have it the renters are moved out and the new ones don't arrive for a least a month.

    Bookmark   March 30, 2010 at 10:17PM
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The drain from Quick Drain USA is beautiful. I was able to modifiy the drain some what and get it to sit flush with the finished walls. We installed this after we removed the old standard 30" tub and roughed in the shower package.

DornBRacht's Big Rain got installed to day and is breath taking! Glass goes in on Friday and we can adjust the globe valves to deliver just the right amount of water to turn an every day tub into a 5 star Spa Retreat.

    Bookmark   May 19, 2010 at 4:03AM
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"The drain was able to handle 22 GPM (Gallons per minute) or 83.3 Litres per minute and this was the max I could get with my homes system and my neighbors hose. "

John, is there any particular reason that you do your own flow-through tests on the drain? How many total shower heads and body sprays will be in this shower?

    Bookmark   May 19, 2010 at 11:15AM
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Too Many to be called a shower. This is a "Water Sculpture".


Last count 11 if you count "Big Rain" as two.

1 Water Fall
1 Big Rain (has two setting - just shampoo and full body coverage)
2 Hand helds (1 reg 1 just cold)
6 Body Jets

    Bookmark   May 19, 2010 at 2:11PM
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Wow. Niagara Falls indoors!

Down here in the Lower least in my part of the Lower 48...that's way beyond what I can put down a 2" drain. I'd need a 3" drain feeding a 3" horizontal branch pipe for that many fixtures.

Each shower head, to include each body spray head, counts as 2DFUs. A 2" drain can handle 6DFUs, a 3" can handle 20DFUs. With 10 heads you're at 20DFUs, well beyond the scope of a 2" drain and right at the max allowed with a 3" drain and 3" branch pipe.

I can't limit the DFU total with diverter valves or by saying that only so many heads will be used at a time. Each head in the shower counts, I have to plumb for the "worst case scenario" syndrome.

You must be under a different code?

Or maybe I just need more coffee!

    Bookmark   May 19, 2010 at 4:11PM
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Mongo this is so border line that we think it will start flooding in about 3.5 minutes. We have anticipated this and installed Globe Valves to restrict the volume of water to a safe rate.

This drain from Quick Drain I install with the exact same specifications at my home and was amazed by the flow rate. We upgraded the old tubs 1 1/4" copper line to a new 2" solid cast. I used a regular and long sweep 45's to roll into the 2"x4" cast wye 3' away from our new 2" solid cast P Trap.

I suspect we will have to restrict the volume of water by nearly 40 percent to make this thing safe. With 1" pex lines we are giving the DornBracht fixtures all the water they want. The engineering in these fixtures is world class. We have been able to fine tune the handle position down to the half mil!

Mongo have any suggestions for fixing a two way mirror to a mat black Marine grade plywood panel. Any adhesive would show and visible clips are out of the questions. I was thinking about 4 tidy squares in each corner. These will be seen but might look OK if well placed.

Any thoughts.

    Bookmark   May 19, 2010 at 9:15PM
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Wow. I'm surprised that you'd install a non-compliant drain system and give your inspector the opportunity to fail the plumbing. Not to mention opening yourself up to liability claims from a flood somewhere down the road.

Water damage can be horrific, remediation ridiculously expensive, and your insurance can refuse to pay the claim leaving you to foot the bill since the installation was knowingly in violation of code.

Be real careful treading those waters. No "water" pun intended.

Is the mirror covering a flat panel screen and can't be captured by a frame? If your installation is what I'm thinking I'll use 100% coverage of a thin band of black mirror mastic, maybe 3/4" to 1" wide or so, around the perimeter of the mirror. Wherever the mirror contacts the wood backer, it gets mastic'd. It ends up blending to a uniform black nothingness.

If your plywood has any significant thickness to it, I'll chamfer the edge of the ply, say at a 45 degree angle, and have the "point" of the 45 touch the back of the mirror. If the edge were just a flat edge, the edge could get illuminated by light given off by the flat screen image, and the edge could become visible to the person on the "mirror side". It's not "visible" visible per se, but it can be a distracting shadow.

    Bookmark   May 19, 2010 at 10:44PM
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Once again as always Mongo - "Solid Advice"

I am building a light feature on this project and am offering a second pair of eyes on another contractor who is building this shower sculpture. This other contractor is my main man Riccardo who has been out on his own since I shut down operations to build my house.

This Water Sculpture if you will is a once in a lifetime project. I may never see it's equal again and to be part of this project was important to me. The designer is outstanding - a computer professor and a brilliant man. The home owner has assumed all responsibilities and has promised to leave the system as we leave it - SAFE AND UNDER FEED

You would have to meet Holger to understand his vision. The shower is an Art Piece. So much detail and thought. Such beautiful fixtures chosen that you almost forget why you entered the room.

I had my plumber rip out the new 2" work that just went in a few weeks ago so I could inspect and source the drop in flow rate. I found many faults and was not please this work had been done without first checking the old drain line. It is not a fun job scraping out years of shower scum, body hair and rust with your finger and a curved file handle. This is what it took to clear the huge hair ball I found and which I'm sure help slow my flow rate.

I also found in attention to the gap in pipe another misaligned fernco which was I'm sure creating another eddy.

I stopped by my plumbing wholesaler on the way into to work this morning and for fun picked up a wack of 3" couplings and 3" cast iron 45's and 22.5's. To my surprise with a little persuading (palm strike!) we managed to run a 3" drain line above the W/C line and have a 2"x3" MJ coupling right at the stack.

The drain is still dropping through the slab in 2" but enters the PTrap that is 3" with another 2"x3" Fernco.

I'm pleased to report that with all systems running "Full Blast" the drain assemble held true with out any water flow being restricted. The test was ran for almost an hour and we noticed at one point the water level rise a 1/4" and then 5 minutes later drop. ??? We think this was from when the upstairs neighbor drained her tub while our test was running.

With these new flow rates I'm calculating a 40 percent restriction will net us a safe "Water Sculpture". We will need help from the upper resident to preform more "What If's"...

You should never build a shower like this! It is so unsafe. Mongo's concerns are just and all his advice should be heeded. I offered the same insight and my client insisted that this is not his shower but his "Masterpiece". I can't myself believe the flow rates we achieved as these flow rates exceed the water volume testing I preformed at my home and exceed published max flow rates from the manufacture.

We are building for an Artist, one who loves water and we have built his masterpiece. My hats off to Holger and DornBracht for putting such gems into our hands. It's sad we are wrapping up in a week.

I look forward to the dinner party...

    Bookmark   May 20, 2010 at 11:48PM
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Quick Drain USA

And there is more.

Love these drains...

    Bookmark   July 22, 2010 at 4:59PM
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We are a manufacturer in China for the trench drainage ,please visit our website

welcome to your inquiry about our products.


    Bookmark   June 10, 2011 at 9:39PM
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