Just curious [Archive] - Ceramic Tile Advice Forums - John Bridge Ceramic Tile


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John K
12-03-2005, 07:09 AM
I had a thought or two on the way home. If a guy uses CBU over plywood in a kitchen and the kitchen floods due to a dishwasher, ice maker etc.
What is the likleyhood that the plywood would swell and cause a tile failure?

Now take the same scenario and say this guy uses Ditra or Protecto wrap or some other membrane system. How would this be effected? Either way the water is going to make its way to the perimeter and seep down into the subfloor.
Is it going to break the bond of the membrane and fail? Or is it going to swell just enough to crack the tile and grout?

Anyway you look at it. It would be a insurance job and the tile company would not be at fault. I was just curious as to other peoples thoughts were. :)

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12-03-2005, 07:17 AM
Yeah, i've thought of all scenarios....i guess if you had exterior rated plywood, with expansion gaps,and modified thinset laid membrane,you'd have about all the protection you could have,unless you planned for it, and used a waterproofing membrane,and ran it up the wall 6"......but that would be crazy,i guess. :crazy:

12-03-2005, 08:16 AM
That is exactly why i dont hook up dishwashers etc, because then if it leaks im in trouble.

We seal inside the dishwasher area fill all perimeter gaps etc with silicone, so if it leaks the water will be seen coming out of the front of the dishwasher and can be delt with in a short time. But the plummers hook it up.

12-03-2005, 08:40 AM
I hadn't thought of sealing the interior of the washer cabinet. Sound's like it's a good precaution. How much extra time and money do you figure it adds to your typical job?

12-03-2005, 03:30 PM
I figure tiling the floor into the dishwasher is a required part of the job. Then some massive "elbow caulk" under there only takes a minute. Just needs to be tall enough like Bryan said kick it forward so it can be spotted.

I had one like John K. described. 3/4 OSB subfloor, then my 1/2" ply (exposure 1 exterior glue) set into super thinset, then ditra & 12" tile. Got a couple inches of water for a day or 2 while they were gone. Destroyed the hardwood on the floor below, but didn't touch my tile or grout. All tile-to-tile plane changes were caulked, not grouted.

12-03-2005, 05:52 PM
Hi Shaughnn,
what tom said, we almost always tile it anyway so just to seal it up only take a few minutes and a tube of silicone around the perimeter and grout joints.:)

12-03-2005, 08:20 PM
On the couple of jobs I've done; even as a rookie (and a dumb one at that), I tile under the dishwasher. I have seen the floor built up (plywood) and tiled in FRONT of a dishwasher and you want to talk about a SERIOUS PAIN IN THE ASS to get that dishwasher out when it needed to be replaced! GRRRRR...

In addition, I caulked extra heavy behind/under the dishwasher area. As far as extra time or $$, I would say that it would be so minimal as to not even count it. By NO means does it have to be pretty. Throw it in there and get out. No-one will ever see it and if they do, that means they were pulling that dishwasher out and will be happy the caulk is in there.

My idea of a flood in a kitchen doing damage - I would think that the majority of the subfloor is made to NOT swell. I thought that they put the subfloor in with the idea that during initial construction, there will be some rainy/snowy days before the roof is on and therefore, they don't use something that would swell very much (if at all). Again, I plead my ignorance here and defer to the professionals. But, as a DIY, I would think that would be the case. No?

sw (shawn)

12-03-2005, 09:33 PM
Oh, I wasn't clear. I always tile into the dishwasher niche also. I just hadn't considered "sealing" it too.