Shower Floor Leaking

[ctgriffi]

Hi, I'm a hands-on guy in my late 30s who loves to fix/build; I have some professional remodeling experience, as well as a few years in the building maintenance industry. I don't know much about tile showers, however, and am looking for some advice on the following:

I'm preparing to add another bedroom to the unfinished portion of a family member's basement, but there's a pressing issue that needs to be addressed first. (This custom home was finished about five years ago and, in general, seems to be well-built with good materials.) The master BR has a large, walk-in, tiled shower that has been slowly leaking into the basement below. As far as anyone can remember, it's been a nagging problem, probably started soon after they moved in. (Yes, they should've taken it up with the contractor immediately, but that's another story.)

The leak is not substantial—a small drip that comes down through the subfloor, where a cutout was made for vent piping and forms a small puddle on the basement floor (always happens right after morning showers). But, obviously, no leak is acceptable when you're preparing to frame up a room, directly underneath.

The shower drain piping is exposed in the basement ceiling and there are zero leaks from those PVC connections. Recently, as a test, I ran that shower for 20 minutes straight while watching the problem area below... didn't see a single drop of water appear anywhere. Then, last night, we did a leak test: sealed off the floor strainer with duct tape, filled the shower with a few inches of water, turned it off and waited... Sure enough, within minutes, a steady drip was coming into the basement below—through the same place it always does.

FYI, the shower floor is tiled with small (1") tiles, and the grout looks quite good on the floor itself, although the perimeter, where the shower floor meets the wall, does not.

So, what are my options? What's the best way to attack this problem? Can I chip out old grout and re-grout those areas? Do we need to demo the entire floor? Appreciate any/all advice or recommendations. Thanks very much!

 

[Sparky617]

Water goes through grout it is not waterproof so regrouting is not going to fix your leak. I suspect the shower pan is bad from an installation mistake. I had to replace mine a few years ago because the pan was installed improperly. It is a complete tear out from the floor up to about a foot to replace the pan.

Mine is a membrane pan. The leak happened at the curb by the door because the guy installing it didn't do the corners properly.

I wish I had a less invasive answer for you, but I suspect my sight unseen analysis is your problem. Definitely fix it before doing work in the basement.

 

[bud16415]

I’m a little confused that it leaks every time after morning showers but you ran it for 20 minutes and didn’t get a leak. You then got a leak after you forced the water back to the edges.

If you wanted to try another test you could hook up a hose or something and have someone spray into the edge as someone else watched and work your way around the base until you found the side that’s causing the problem. Or you could try fixing it by sealing that inside corner all the way around with a sealant suited for tile.

The correct way would have been to turn it in to the builder right off the bat but for some reason that didn’t happen. The next correct way would be to have it all rebuilt as described in the above post.

 

[CallMeVilla]

I like to go from the basic to the difficult. Yes, you could rip out the pan and re-do it. Let's try the following:

1. Let the pan dry as much as feasible.
2. Scrape the grout from the corners and re-seal with quality bath caulk. While you are at it, do the vertical corners too. Don't forget the curb.
3. Re-seal all the grout lines in the floor TWICE. Let the sealer setup between applications.
4. Allow all sealer to cure.

Try the leak test again making sure to completely seal the drain flange. If you get no leak, great. If you get a leak, the problem is isolated at the flange. That could be very bad news but lets not borrow trouble ...

 

[ctgriffi]

Well, not great news, but not totally unexpected either. Thanks for the insight, Sparky. (and all others... didn't realize that a few more posts had just appeared!)

In terms of the "sight unseen analysis," I could post some photos of the shower, but I'm guessing that wouldn't be much help. Getting eyes on anything would mean cutting a good size hole in the bedroom wall behind the shower, and that still won't show what's happening underneath.

 

[ctgriffi]

I’m a little confused that it leaks every time after morning showers but you ran it for 20 minutes and didn’t get a leak. You then got a leak after you forced the water back to the edges.

That confused me too, Bud. I think it's because my 20min test had the shower head pointed mostly at the drain. The leak(s) seems to happen when water is concentrated around the edges of the shower floor, which might happen more when somebody's in there, directing spray all around. (It is a pretty good-sized shower.)

 

[ctgriffi]

I like to go from the basic to the difficult. Yes, you could rip out the pan and re-do it. Let's try the following:

1. Let the pan dry as much as feasible.
2. Scrape the grout from the corners and re-seal with quality bath caulk. While you are at it, do the vertical corners too. Don't forget the curb.
3. Re-seal all the grout lines in the floor TWICE. Let the sealer setup between applications.
4. Allow all sealer to cure.

This is pretty much what I was planning on doing, as a first attempt. I guess I wonder how long-lasting this fix might be, if it does seem to correct the problem.

Any recommendations on quality bath caulk and good grout/tile sealant?

 

[bud16415]

That confused me too, Bud. I think it's because my 20min test had the shower head pointed mostly at the drain. The leak(s) seems to happen when water is concentrated around the edges of the shower floor, which might happen more when somebody's in there, directing spray all around. (It is a pretty good-sized shower.)

If by going around it and finding maybe just one area where the leak is getting thru you could then try using bath and tile caulk in that area only and if the problem goes away great if it comes back maybe you could remove tile in just that area and see if you can seal it.

 

[CallMeVilla]

I had an upstairs shower leak thru the downstairs ceiling light. Great fun.

I opened the wall behind the mixing valve and supply plumbing to get a better look. TAH DAH! The leak was coming thru the tiled soap holder on that wall. I scraped all the grout around the soap holder and anyplace else on that wall. Re-grouted. Re-sealed the grout.

BOOM! Problem solved plus the bonus of installing an access door to the copper plumbing. You might consider this approach to see if the leak is around your shower fixture too.

 

[ctgriffi]

I had an upstairs shower leak thru the downstairs ceiling light. Great fun.

I opened the wall behind the mixing valve and supply plumbing to get a better look. TAH DAH! The leak was coming thru the tiled soap holder on that wall. I scraped all the grout around the soap holder and anyplace else on that wall. Re-grouted. Re-sealed the grout.

BOOM! Problem solved plus the bonus of installing an access door to the copper plumbing. You might consider this approach to see if the leak is around your shower fixture too.

With the shower off and a few inches of static water sitting there, it was steadily leaking, so I think it's probably the floor, although I agree it seems prudent to get a look at the back of the fixture/supply area.

 

[havasu]

I'd first check to see how the drain is connected to the pan. Might save yourself big bucks.

 

[ctgriffi]

I'd first check to see how the drain is connected to the pan. Might save yourself big bucks.

I can actually see the drain connection pretty clearly from below, and everything looks great (dry) there. Maybe I'll take another at that soon, though; might be helpful to see what kind of pan was used.

 

[user 4883]

On another note make sure the basement has legal egress otherwise you maybe wasting time & material by building a bedroom there.

 

[nealtw]

Is there a bench in the shower. Cut into the wall from other rooms to inspect from outside where you will find drywall behind the tile and all kinkds of other no, no's

 

[CallMeVilla]

With the shower off and a few inches of static water sitting there, it was steadily leaking, so I think it's probably the floor, although I agree it seems prudent to get a look at the back of the fixture/supply area.

If you never splashed on the walls, this is a good test ... but the leakage will accumulate in the floor if it comes from the walls and you might not be able to ID the source. Oh, and you are SURE the drain flange was sealed when you did the test ... ?

 

[Sparky617]

Water will go through grout, if it didn't there wouldn't be a need for cement backer boards and shower pans of all varieties. Water splashing on the walls is expected and should not cause a leak. If the area around the the drain is dry you can make a pretty good assumption that the drain is working properly and is sealed to the pan. There are weeping holes in the drain below the tile surface to drain any water that comes through the grout and into the pan. 99% of the water goes down the visible drain without going through the grout, but the grout does get wet and some of this water will work its way down instead of evaporating up. Also, any voids in the grout or caulk will allow the water to pass through to the pan more easily.

If your test of blocking the drain and filling the base of the shower with water produced a leak after several hours I'm sticking with my original diagnosis that your pan is leaking and likely from a mistake during installation. I was unsuccessful in getting my builder to fix mine. I finally had to call in a tile guy and have it done at my expense. My tile guy showed me how the installer screwed up the corners around the curb at the door.

 

[ctgriffi]

If your test of blocking the drain and filling the base of the shower with water produced a leak after several hours I'm sticking with my original diagnosis that your pan is leaking and likely from a mistake during installation. I was unsuccessful in getting my builder to fix mine. I finally had to call in a tile guy and have it done at my expense. My tile guy showed me how the installer screwed up the corners around the curb at the door.

Just to clarify, after a normal shower, there is usually a small puddle that appears down below—sometimes it's only a few drops. But, when I sealed the drain, added a couple inches of water, shut it off and waited, within a few minutes there was a steady trickle of water coming down in the exact same area.

And, actually, as I mentioned once before, I ran the shower for 20 minutes recently (as a test, no one in there) and didn't see a single drop come down. Could the weight of large human beings be a contributing factor to this pan issue?

 

[slownsteady]

Just to clarify, after a normal shower, there is usually a small puddle that appears down below—sometimes it's only a few drops. But, when I sealed the drain, added a couple inches of water, shut it off and waited, within a few minutes there was a steady trickle of water coming down in the exact same area.

And, actually, as I mentioned once before, I ran the shower for 20 minutes recently (as a test, no one in there) and didn't see a single drop come down. Could the weight of large human beings be a contributing factor to this pan issue?

Sure, why not? A 150 pound weight may cause deflection in the shower floor if it is not properly supported. But that may show up as loose or chipped grout from the flexing.

 

[Sparky617]

Just to clarify, after a normal shower, there is usually a small puddle that appears down below—sometimes it's only a few drops. But, when I sealed the drain, added a couple inches of water, shut it off and waited, within a few minutes there was a steady trickle of water coming down in the exact same area.

And, actually, as I mentioned once before, I ran the shower for 20 minutes recently (as a test, no one in there) and didn't see a single drop come down. Could the weight of large human beings be a contributing factor to this pan issue?

It could also be where the water was hitting the walls when you ran it without anyone in the shower. Stopping the drain up and filling it up with several inches tells me your leak is in the pan, likely in one of the corners. Given the age my bet is you have a membrane pan unless your local codes requires a lead or copper pan. A membrane pan is made from a heavy synthetic rubber membrane. It is folded into place without cuts in the corner to remove the excess material. If it were cut in the corners it requires glued corner pieces to seal the cuts. Here is a good video on installing membrane pans. https://www.youtube.com/watch?v=dRwu1SE_***

 

[ctgriffi]

Here is a good video on installing membrane pans. https://www.youtube.com/watch?v=dRwu1SE_***

Tried to watch that vid, but couldn't get the link to work. Could you repost, plz?