To: “Breaktimeâ€
As if contractors don’t have enough problems with leaks in other people’s houses, I have a frustrating situation in my own place. The bathroom tub leaks at the interface between the bottom row of tile and the short lip at the edge of the tub. The gap between the two is a quarter inch, and was previously grouted, which is not a very good water barrier. Once the water hit the old 1940’s 1×6 floor sheathing, mold started to grow and the smell pervaded an adjoining bedroom. I have opened that wall from the bedroom side, since I did not want to rip out the tile and the wonder board substrate. I cleaned up and treated the mold on the surface of the sheathing and on the bottom side that faces down to the crawl space. Obviously, I could not clean the top of the floor joists, but when I ran a bead of good marine caulk at the leak spot (and then caulked on top of that with sanded caulk to match the grout), the smell disappeared.
Several months later it started smelling again, and on investigating under the floor, I found that the sheathing was wet and the mold had regrown. The only remedy I can think of is to run an even bigger bead of marine caulk and cover the interface with tile quarter round, which would be glued in place by the marine caulk.
Does anyone have any other suggestions? I am willing to open the wall again, but I don’t want to take out the tub and tile.
Bay Area Bill
Replies
Bill, you mention crawl space below. Granted the mold problem may have started at the leak you had at the tile/tub area, but do you think the moist atmosphere of the crawl could have started the spores growing again. How much opening is there between the crawl and the trapped area under-behind-around the tub?
Remodeling Contractor just outside the Glass City.
Quittin' Time
You got problems in River City, guy.
I'd carefully remove the bottom course of tile with a dremel grout tool and a stiff putty knife. You can then explore if the setting bed and substrate are wet. If so, your leaks could be from the tile installation above. I think your problems are more than that simple caulk joint. I can not believe that the miniscule droplets of water that might get through a poor caulk joint are causing this problem.
If it is merely that joint, I would use some backer rod to close that quarter inch gap at the bottom and top the backer rod with 100% silicone caulk. Tape each side of the joint and caulk and tool the joint.
Mold needs two things: water and an organic supply of food, like wood. You might also want to waterproof the subfloor and the wall below the tub. Use poly, trowel on waterproofing, something to bead up that moisture.
But I think the problem runs deeper than that stupid joint. Only a partial demo will tell.
Regards,
Boris
"Sir, I may be drunk, but you're crazy, and I'll be sober tomorrow" -- WC Fields, "Its a Gift" 1934
I fear that you are right and that there are deeper problems than the caulk joint. Someone in the boating store where I bought the marine caulk said that when he was in the Navy they temporarily "glued" a large, very heavy engine mount to the stern transom with it. The problems with backer rod are that the substrate does not extend down to the tub and that the marine caulk will be very hard to remove. I'm worried about tearing up the wonderboard substrate if I try to remove that first row of tile. When I opened up the wall behind it before, it seemed pretty dry at that joint, so perhaps you're right in guessing that the grout should be sealed again. It's been a long time. How often would you recommend? I can seal the subfloor where I can see it, and I can see it from below (3-4' well-vented crawl space) and from above since I can open two walls, one of which is the wall with the plumbing, which wasn't leaking when I opened it before. The third wall is an exterior wall, so naturally the subfloor sits on the top plate of the pony wall below. But short of pulling the tub, I can't see any way to get at whatever mold is growing on the top of the joists under the 1940's subfloor, i.e., replace the subfloor. We have one bathroom. Gag! Have you ever heard of any mold-killing product that I could force into the places I can't get at to clean, short of a tactical nuclear weapon?
P.S. There was a story that at a fancy party Winston Churchill was reprimanded by a snooty society lady who said "Sir, you are drunk!" He replied that "That may be true, but you are ugly, and in the morning I'll be sober and you will still be ugly." Could both his remarks and W.C. Fields' be true? Even though it seems too coincidental, I'd like to believe both stories are true. W.C. is also a favorite of mine.
How old is this bathroom?
Both quotes are similar. I can't imagine a politician saying what is attributed to Winston Churchill. I do know that WC Fields made that quote in a movie which I own and watch annually. He was not above stealing anything for a laugh.
Regards,
Boris
"Sir, I may be drunk, but you're crazy, and I'll be sober tomorrow" -- WC Fields, "Its a Gift" 1934
The distance between the subfloor (1940's 1x6 fir) and the soil is 3-4', so there is little chance of contact. The area is well-vented and near the access door. However, there is mold on the surface of the soil and the area is wet in the winter. The previous owner did not disclose that there were any problems with mold. There was nothing apparent when I initially inspected it before buying, but I was perplexed later when I found a lot of dry dirt on the mudsill and a shallow trench along the footing when I did the seismic reinforcing. You may think that the dirt on the mudsill spread the mold, but it was completely dry and not moldy. I tested (or tasted) it all along the footing when I nailed off the shear on the pony walls, and the air exhaust from my framing gun blew the dust all around, even though I did my best to clean it off before nailing. By the way, one of the first things I did in the crawl space, since I knew I was going to be down there a lot in the course of various remodels, was to install a receptacle and a couple of lights. I highly recommend doing that, and it made mold spotting easier (but no less depressing).
No way it's sweating pipes putting just enough water down on the deck to start up that mold again? Just seems it's be hard for that water to get up and over the tub lip. The tile or concrete bd go down beyond the lip? Hey, best of luck on this.Remodeling Contractor just outside the Glass City.
Quittin' Time
The pipes were dry when I first opened the wall they're on; no leaks either. Unfortunately the tub doesn't have much of a lip, and the substrate, wonderboard, doesn't reach that lip.
Seal the grout. Then splash water from an outside hose, to tell if the leak is from the tile. If it leaks later when showering, it may be the pipe.
I had a leak one time (ten or so years ago) that I thought was a drain pipe from the tub - cut open the ceiling and sure enough (I thought) there she was, dripping off the threads of the galvanized pipe. Got out the sawzall, some plastic pipe, a few adaptors and after about two hours she was fixed (?).
Turned out that the real leak was coming from the grout on the top surface of the soap dish, the water was traveling down the wall and running along the tub lip behind the wall, finally falling on top of a pipe. To make matters worse, it only occurred when I took a shower and not my wife because of our height differences and thus the angle of the water spray.
Hopefully your diagnosis was/is better than mine.
It may well be water leaking through the grout, since I have not sealed it in a long time. I'll definitely do that. Unfortunately, I'll have to open the other side of the tiled wall once more in order to clean up the mold. But that's a relatively easy thing to do: I'll just remove the piece of rock I put in a couple of months ago, and go to it. I suppose I could always use more practice matching plaster textures . Do you know of any product that works better to kill mold than bleach followed by soap and water? Thanks, Bill.
A couple of ideas come to mind. First leave the wall open after this repair so that you can check for more leakage. If the backer does not reach down to the lip, is it at least out far enough to drip onto the tub, or is it missing completely. Is there a vapor barrier in the crawl space? Dry powder may help locate leak, so you know if a local spot or spread around. Thick coat of "Bathroom" paint may at least slow it down, but you still need to stop the moisture. Good luck
Dan
Thanks for the suggestions, Dan, or should I call you by your last name, Handy? I've already decided to leave that wall open for at least 6 months, so we're thinking along the same lines. I believe that the substrate does not go all the way to the tub, so maybe I can come up with some way to divert any water onto the tub. Insert some kind of flashing from behind??!!. Incidently, my wife reminds me that when I had the wall open before, there was much less mold on the bath/bedroom wall than I expected. And there was no mold at all in the plumbing wall, which the bath shares with the bedroom closet. Nevertheless, the bedroom smelled strongly of mold. Perhaps some of that was Eau de Crawlspace. We'll see when I reopen that wall.