Leaking pan - how to locate source?

[dhoerl]

I had a new home built that was finished in 2001, with a large 2-person shower (5' x 6', tiled). The shower pan was a rubber mat and laid directly on the plywood subfloor, with one 3" glued seam. Tapered mortar was laid over it, then the tile (I now know this was not the best way to do this). The shower walls are cement board. After 4 years of no problems, I sold the house to a couple to whom I have maintained a good relationship.

Now, after 5 years of use, the shower has developed a serious leak (its over the kitchen) - water dripping out after a short shower. There is no water damage anywhere near the drain.

Tests have showed that filling the pan with a few inches of water results in leakage (knocked some holes in drywall to better observe subfloor.) There is no obvious change to any of the seams from when I lived in the house (the seams had grout in them, not caulk, and at one point were in need of repointing, which I did just before the house was sold).

If I can help then find the area that leaks, its at least possible that pan could be repaired - it may not be likely but its possible. If the leak could be tracked to one seam (ie one joint between wall and floor) most of those areas are accessable from the outside, and its possible the dam block could be removed and the pan patched (assuming some idiot put a nail through the Durarock, etc).

What I was thinking of doing is running beads of Lexel caulk (it can be installed on wet surfaces!) on various seams, then testing for leakage. However, my (maybe silly concern) is that its going to be hard to remove the caulk once the leaking seam is found. Does this sound like a good strategy?

Any other ideas?

David

[jadnashua]

Are you sure it isn't th esupply valve or joint where the showerhead is attached?

Your shower was not built per code...it requires the waterproofing to be sloped so any water that gets to it can drain - when it is flat, any (small) amount that reaches that level sits there and stagnates. This can build up quite a bit.

It could be they did some other things wrong, too, like put nails in the liner over the curb and now the level of water below has reaced them, or they may have blocked the weep holes in the drain, preventing any water that could escape to do so.

You'll get really good info on tiled showers at www.johnbridge.com.

My guess is that you'd have to at least tear out the pan and a foot or so of the walls to install a new one correctly. You may also need to repair the subflooring. If you are lucky, it could be from the valve or supply piping and you can get to it , but it doesn't sound like it.

[dhoerl]

Well, here in NJ it was not (and I still don't think it is) required to slope the pan membrane, even though I now know it would be better to do so (have a different house now, redoing the master bath, and tile guy told me to do this).

We pulled the sheetrock off the area where the shower arm attaches, and the thermocontrol (Grohe), and its dry as a bone [this was my first hope as its easy to fix.]

The weep holes could be blocked, but even with stagnant water in the pan, the membrane should be able to hold a few inches of water indefinitely. However, if the weep holes are blocked, yeah, the water would sit and seek any hole.

I'll bet that with a 5 - 10 gallon shower (say 2 minutes), about 1 to 3 cups of water leak out.

I am thinking as you suggested its either a low nail, or even a cut caused by someone stomping on a piece of fallen DuraRock.

Half the shower is reachable from outside (common wall to the rest of the bathroom). I was even thinking of pulling all the sheetrock off, then trying to get remove the 2x6 blocking at the floor (creating the dam) so as to see the bottom of the durarock and maybe a bit of the pan, with the idea that if I could find the nail or hole near the floor, it could be patched. This is a long shot for sure, but given the cost and aggravation of totally removing the pan - well, maybe its worth the 4 or 5 hours to do it.

David

[geniescience]

David, i think you have a good grasp of the issues. A sloped membrane, and a "full" pan under the tiles if it is not sloped.

Well, here in NJ it was not (and I still don't think it is) required to slope the pan membrane, even though I now know it would be better to do so (have a different house now, redoing the master bath, and tile guy told me to do this).

but i do think that little sentence in the Code was always there, regardless of how people used to read it. Some people claimed that tiles-and-grout-all-together, and well done too, would be the waterproof layer, and that was what Code required. Not true.

david

[jadnashua]

All drains are required to have a slope. Why people think that the liner, which is a huge drain system, doesn't, just doesn't make sense to me. Tile and grout is water resistant, but there will always be a little bit of water that gets under the tile, for whatever reason or fault. It just makes so much sense to make that able to flow to the drain rather than sit in the pan and fester...