How to fix liner problem on shower base [Archive] - Ceramic Tile Advice Forums - John Bridge Ceramic Tile


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01-10-2005, 02:06 PM
I've been building the shower base in my 4x6' shower after reading many many articles and posts about it. I've run into a problem and I'm not sure how to fix it.

I did all the normal stuff through the creation of the pre-sloped mud floor. It was looking pretty good, although my mortar skills are that of a novice and I wished I'd sloped it more to reducec the possibility of flat spots or depressions for puddling. I'll know better next time. Anyway, on to the real problem. I marked and cut the liner, folded it all up nice, and dropped it into place for a dry fit. Ahhh, it was so good, even though the walls aren't perfectly square. I was pleased. I marked on my liner where the drain would be, and following my instructions, solvent welded a large "patch" of the liner material there to reinforce it. The solvent weld was difficult, as it kept coming loose while I manipulated the liner and would get the solvent all over the place, messy. I kept putting it back in place until it set and stayed. I apparently could've done that step better. Anyway, it was in place, but not pretty, so onward ...

When it came time to actually put the liner into place, one of the sets of directions I had read recommended a layer of roofing tar underneath it. Curiously, another set of instructions I had by the same (well-known) author, did *not* include the roofing tar under the liner. But it seemed like a good idea to me, to make the liner lay flat against the pre-slope and adhere well. So I did it. Then I located the drain and cut out the opening there.

Following my directions again, I applied the noble sealant caulk to the drain as I was putting the liner in place to seal it. Then put the top part of the clamping drain in place, cut openings for the screws, and started bolting them down. After a minor mis-step with dropping a bolt down the drain (stupid newbie mistake) and retrieving it, I finally had the liner in place, bolted down properly to the drain, flattened and tar'ed to the pre-slope, and properly stapled to the walls blocking above the curb height. Looked real nice at this point.

The following day, when I went to admire my handiwork, I noticed that around the clamped-down drain ring, about 1" away from it, the liner had kinda buckled upwards, creating an evil ridge that would prevent water from reaching the weep holes properly. Argh!

I did my leak test, to see how bad the situation was. On the plus side, there are no leaks. But, as expected, the water doesn't drain down to the weep holes properly. I appear to have two problems. First, I think the weep holes themselves are plugged, either by caulk/solvent debris, or because they were just very small weep holes and the clamped drain is very tight. Water sitting right at the weep holes isn't weeping away. I was going to try tonight to see if I could ream the weep holes out with some very thin implement of some sort. Assuming I can get the weep holes cleared, the second problem is more daunting, whether I can overcome this ridge of liner surrounding the drain. As it is now, it would keep small amounts of water that reach the pan from even getting to the weep holes.

Any ideas or recommendations? At this stage of the game, and with the liner tar'ed down to the pre-slope, tearing out and re-starting would be a *huge* setback and add weeks/months to the project given the time I can devote to it.

I'm willing to settle for a not-perfect job, as long as I can avoid pools of stagnant water sitting on the liner.



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01-10-2005, 02:31 PM
Jim, just get the weepholes working. The mud will a) hold the ridge down so the water will pass over it, or b) allow the water to seep over it by capillary action. In either case, if your weeps are weeping, you won't be. :D

01-10-2005, 02:33 PM
If you losen the clamping ring can you pull the liner (wrikle) toward to drain and flatten it out? there should be no sealant above the membrane around the clamping ring.(only under the liner to ring)

01-10-2005, 07:42 PM
Thanks to your replies, I was somewhat re-assured. Here's what I did tonight ...

I don't think I could reposition and flatten the liner around the drain since it's attached with roofing tar around the drain and the double-ply liner there is very tough and inflexible. in retrospect, I don't think I needed the reinforcing patch since the material from Noble was already some pretty tough stuff in a single ply.

I tried to ream out the weep holes using a very thin guage wire. It wouldn't budge, not at all. So I went ahead and loosened the bolts and pulled the top half of the drain off.

Then the problem was obvious. The two-ply liner, where the reinforcing patch had been applied, had "swelled" as the drain ring was clamped down (perhaps too zealously). So the liner itself had swelled up into the channel for the weep holes and blocked them.

I very very gingerly used a razor knife to trim down this swelling and create a channel. (Then moved the razor knife far far away ... that liner cuts like butter) After re-attaching the ring drain, I did another test. I poured some water around the drain, and then to really see what was happening I put a drop of food coloring close to each weep hole. Happily, 3 of 4 are now draining okay.

Is this good enough? Do I need to take the drain clamp off and try to clear the 4th one too?

Also, I'm not sure the "ridge" in the liner around the drain will be pushed down by the top bed of mortar. It's pretty tough to press flat by hand, and it seems more likely that it will press up into the mortar instead of being flattened by it.

Thoughts? Recommendations?

How much water really gets to the pan? Does that only happen when water makes it through the grout and works its way through the mortar bed? That seems pretty tough. I was also considering a layer of redguard on top of the top mortar bed to waterproof it even more, but past posts seem to imply that this is a bad idea.

Thanks for all your ideas!

01-11-2005, 11:21 AM
bumping back to the top

01-11-2005, 11:48 AM
A lot more water reaches the pan than you'd think. If the weepholes are working properly, you'd never have to think about it all.

The good news is that with functioning weepholes, old water in the mud bed will constantly be replaced by new water. The new water will bring a bit of chlorine with it, thus helping to control the mold.

I think 3 out of 4 weepholes will be sufficient. Remember to create a drainage bed of pea gravel or broken tiles near the weepholes, since you don't want to pack them full of deck mud.