WATER PROOFING A SHOWER BASIN

[Bri]

Hi Everyone

At the risk of sounding like a schluter rep, I just finished watching the Schluter installation CD(no, I don't have a life)...and since I've had some luck with the Ditra system lately, this Kerdi waterproofing system has me intrigued. You build your slopes and curb with mortar and then after it dries, you set the kerdi matting over the mortar bed with modifed thin set. It goes over the curb also, and up the walls too if you want. The matting is covered with a fleese on both sides, so you set your tile directley over the matting. Any joints in the matting are covered with additional matting, and attached with thin set. It seems like a really easy way to waterproof a shower, I'm just not to sure about the seams..won't water seep along the thinset at the seem patches?

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[Rob Z]

Hi Brian


I need to type fast, because my daughter is demanding the use of the computer to go to Disney.com.

I have viewed the Schluter video (I'm not hi-tech enough to figure out a CD), and the two things that concern me are:

1. The flanged drain assembly is made out of ABS. All the plumbing around here is PVC. There are ways to deal with this problem, but it's cumbersome. There's only one place around here that I know of that sells ABS fittings.

2. The flanged drain assemblyis set into fat mud, while the rest of the floor is floor mud. It seems to me that that small amount of wet mud to set the flange must be weak, and prone to shrinkage compared to the surrounding dry floor mud.

I'm not concerned with the thinset-bonded layers-that's how Noble sheet products work, and it seems that if there was a problem they would have found out by now.

Let's see what the others say. John will think it's a communist conspiracy to build a shower out of drywall and anything less than about two tons of mud.

Rob

[John Bridge]

Yeah, you pinkos. You're robbing food from the mouths of my children, etc., etc.

I just happen to have the Schluter catalog here and it says:

"If exposure to large quantities of water is anticipated, construct the joints using an epoxy resin adhesive or other suitable sealing material."

ABS parts can be welded to PVC parts using multi-purpose glue. Oatey makes one.

The beauty of the conventional shower pan is that it is one piece (usually).

[Rob Z]

John

The multi purpose glue is useable for ABS-ABS or PVC-PVC or CPVC-CPVC, etc., not one to another. Lots of plumbers and others do it, though. On one of my jobs a few years ago, the inspector failed the plumbing rough in because the plumber glued ABS to PVC. After much discussion, he had us cut out the joint in question, cut it in half with the mitre saw, and we saw the incomplete coverage/voids all around the perimeter of the fitting.

Here in No VA at least, ABS to PVC will fail to pass.

Rob

[chip]

The overlaps should be on the down slope so no water will be able to work its way under the membrane.

What I can't figure out is , what is the benefit of the drain over the standard issue drain with flange found in most showers?

[Edited by flatile on 06-17-2001 at 02:06 PM]

[Rob Z]

Art

The drain that Schluter has is designed so the Kerdi is thinset bonded at the elevation just below where the tile is set. There is no clamping ring or need for a sloped sub layer of mud below a pan liner. One application of mud is all. The curb is made out of drywall over 2x"s.

Rob

[Bri]

Hi
I guess it would be possible to use the kerdi with a conventional clamping ring drain....kinda like that square drain though....not much nipping.

[Rob Z]

Bri

I would like the square drain, too.

I just posted over at JLC to see if anyone has used the Kerdi drain.

I'm not sure this thing will be a time saver over some of the stuff that Bonsal has now. The curb they make is real quick. Have you used it?

Careful what you say, I think Art P. is lurking around here somewhere.

Rob

[John Bridge]

I didn't know about the problem with ABS/PVC. Hmm, wonder how many times I've done that?

I guess then the thing to do would be to glue on a piece of ABS pipe, excavate a little (or open the floor) and use a "band-aid" to join the two materials. Or am I just belaboring the issue here?

[Rob Z]

Hi John

Not belaboring, but it just bugs me that I would have to make a separate trip to the supply house that stocks ABS and buy ABS fittings, more complications on a product that is supposed to be a labor saver. I mean, who cares if California still uses ABS?

[kalford]

Guys,
I use to remodel mobile-homes in FL. and have done extensive plumbing work.Back then toilet flanges only came in ABS while the drain pipes were usually PVC.We used Oatley "blue" pipe cement which will cure under water.We chose it because we did alot of water-line repairs and many times didn't have the luxury of working with dry pipe.At any rate,of all the hundreds(literally)of ABS to PVC unions we fabricated I can't think of a single problem.

[chip]

I'm not sure of the price of Kerdi, but I would bet that there are trowelable water proof products out there that would work with extend-a-drain for less money & time.

Any experience with extend-a-drain?

Trowelable membranes?

Art

[John Bridge]

Well, I whipped up to Terry Love's Plumbing Advice Board to get an opinion on the ABS to PVC thing. Terry operates in the Seattle area where I grew up. He's a "West Coast" type dude, too.

http://www.terrylove.com/wwwboard/messages2/18050.html