Finding correct wax seal for 70-year old bathroom. Smell won't go away!

[Jadnashua]

First, a shower, like any drain, should have 1/4" per foot slope towards the drain. Second, many people seem to think it's okay to build a shower with the waterproof liner flat on the floor...water needs slope and gravity to flow. So, in many incorrectly built showers, water ends up sitting under the tile and can grow nasties while starting to smell like a swamp. Mortar is alkaline (pH greater than 7), which tends to inhibit some growth. But, eventually, when soaps, oils, etc. get into that water below the tile, it becomes acidic and supports growth of more crud. This can take a number of years, depending on use. So, it could just be they didn't build the shower correctly.

 

[Gary Swart]

The way to deal with that flange bolt that won't hold is to put a nut on it to hold it tight to the flange. There is plenty of space between the flange and the underside of the toilet to do this. This trick also helps hold those flange bolts upright when you are setting the toilet.

 

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[KCEdds]

Quick update on my situation: I put a wet towel over the drain in my stand-up shower and the smell went away. I'm now fairly certain that the smell is coming from the shower, but as opposed to there being mildew/mold forming under the tile, the smell is sewer gas. It smells just like it did when I took my toilet off the the flange.

So my new question is: How can a shower on the second floor (third if you consider that our basement is ground level in the back of our house due to the yard slope) have a sewer gas smell? Our basement shower has that smell when the water in the trap evaporates, but that's because it's so close to the main line I'm assuming. Our 2nd floor shower didn't have this smell for five years, and then all of a sudden something changed.

I have to snake this drain ever six months because my wife's hair clogs it up gradually over time. But I snake it and then it drains fine. Did I perhaps damage it the last time I snaked it? I feel like I went deeper the last time than I ever have but what could I have done?

Thanks!

 

[Redwood]

Proably not!

Is there water in the trap?

If so then the smell is coming from above the water level.

 

[KCEdds]

Proably not!

Is there water in the trap?

If so then the smell is coming from above the water level.

I'm not sure how to tell if there is water in the trap. Any advice?

Thanks!

 

[KCEdds]

Proably not!

Is there water in the trap?

If so then the smell is coming from above the water level.

And if the smell is coming from ABOVE the water level, does that mean I have a clog somewhere that I don't know about? Would draino cure that? What's the cause/cure if it's coming from above the water level?

 

[Redwood]

Look down the drain. do you see standing water in the trap? yes would be a good answer.

If the trap is offset and the trap is not visable flom above run water in another fixture, do you hear running water in the shower drain? No would be a good answer.

 

[T_Finan]

Some random thoughts from a non-professional:
-hair can cause some type of capillary action which breaks the seal of the shower trap and cause the gas to get through
-Do you have a basement shower? make sure it has water in its trap.
- is the main roof vent stack clear and unblocked?

 

[KCEdds]

Some random thoughts from a non-professional:
-hair can cause some type of capillary action which breaks the seal of the shower trap and cause the gas to get through
-Do you have a basement shower? make sure it has water in its trap.
- is the main roof vent stack clear and unblocked?

Great questions. A couple of follow-ups.

1. If hair broke the seal of the shower trap, how do I diagnose that this is what happened and how do I fix it? Have a plumber tear up my shower tile and get down in there?

2. We do have a basement shower, and ever since we've lived here we have filled it up with water once a week (sometimes much longer) to keep the smell out of there, but it's NEVER affected our 2nd floor bathroom.

3. We have a Dutch Colonial with a slate roof so I can't easily get up there to check out the vent stack. But we have lots of squirrels up there. Maybe they dropped some acorns in there? Should I pay to have that snaked out first before I have the shower drip pan replaced or water trap seal checked out?

I did notice that in the corner of the shower where the floor doesn't seem to be angled up high enough for the water to drain properly that there is some new black mold on the grout.

Thanks

 

[Jadnashua]

The ideal location for the shower drain trap is directly underneath the opening in the shower. If yours is there, with a flashlight, you should be able to see the reflection of water. If it is offset somewhere else, then any hair, crud, etc between the trap and the drain will be uncovered and could start to smell nasty. Hair caught part way through the trap could wick water out of the trap, but it would usually take a few days. Snaking through a trap could create a hole if done frequently. If the trap is metal, it could be rusted out and slowly leak and dry out.

If the shower wasn't put in by a plumber or inspected, they may not have put a trap in at all!

 

[T_Finan]

Re #1, jadnashua explained it better than me, "wicking" the water away like a siphon rather than "breaking" it.

Please explore the internet for a good picture of what a shower pan drain looks like(I recall a forum like this devoted to tile "mike bridges" perhaps that had a good one).

I think you'll see the towel over the drain is too high to prove your point. I think you'd need a ballon in the drain below where the pea gravel bed empties to prove it was coming from outside versus under the tile.

Try dumping a gallon of bleach on the tile and letting it sit. This would fix my problem for a couple of days.

 

[KCEdds]

Okay, I might have figured out what the problem is, but I'm not sure.

I removed the shower drain cover and noticed that one of the screws had cracked the PVC pipe, or whatever it is that it's screwed in to. It didn't just strip the hole where the screw goes, it actually cracked the whole pipe.

I'm guessing water could potentially seep through that crack and cause mold, but wouldn't it just land in the drip pan under the tile?

Oh, and I did see water in the trap and when I ran the water in the sink I didn't hear any running water in the shower drain. So I'm guessing that's good news.

If it it mold that is causing the smell, it sure does smell like sewer gas.

 

[T_Finan]

It is unbelievable how much smell something that can fit under tile can cause. I really think you've found the problem.

I found a tile guy who built a properly pitched new floor with membrane over the existing tile, effectively starting fresh. This saved the expense of a pan replacement since it was not leaking to below.

 

[Jadnashua]

As I said earlier...if the liner was installed flat on the floor, in a well-used shower where it can't dry out in between (i.e., used daily), about 5-years is how long it takes to change the pH of the accumulated crud and start to grow things inside of the pan. Not saying this is your problem, but it could be. A crack in the drain pipe right at the top probably wouldn't be a major issue. Right above the liner there should be weep holes that allow any moisture tha accumulates under the tile to flow down the slope of the liner, through those weep holes, and into the drain. A crack above the liner just would act like a second weep hole. Another common mistake when building a shower pan is to not put some pebbles or something by the weepholes to keep them open so they can actually drain.

Personally, I prefer the Kerdi system by www.schluter.com. This puts the waterproof layer immediately underneath the tile, allows unlimited size and configurations, and produces a superior shower. Moisture has nowhere to go, so less gets wet, and there's less chance of any accumulation and therefore mold or that swamp smell. Wedi works in a similar manner, but is a little less forgiving in making some custom sizes but works well.

 

[KCEdds]

Update to mysterious smell

Hi Everyone,

So I've been keeping wet paper towels over our shower drain, which temporarily stops the sewer smell, until I could have the tile ripped up and a plumber take a look at what the problem is.

Well, now two weeks later (the tile guy got delayed in starting the work) the smell seems to be gone. No more wet towels covering up the drain and we haven't had the smell in days.

We've also been showering in there 1-2 times a day this entire time. And there's no water damage on the ceiling below.

This is really weird. As soon as we covered up the drain the smell was "contained" so I was sure it had to be the shower. But why would it just go away? Could the cold weather outside have any effect on what's causing the smell? Specifically if it's mold in the drip pan?

 

[Kingsotall]

Did we ever find out for sure that there was a p-trap plumbed¿

 

[KCEdds]

Did we ever find out for sure that there was a p-trap plumbed¿

Hi Kingsotall, by "plumbed" do you mean did a plumber take a look at it? Or was it ever snaked? Sorry, I'm a neophyte.

Or that it's a p-trap as opposed to a different type of trap? If that's the case, I can say that when I look in the drain with a flashlight I see water down there, and when I run the sink and flush the toilet I don't hear any water running in the shower drain. All good things, right?

 

[T_Finan]

Look at this picture

See the hole(s) in the drain pipe next to the crushed gravel? I think you are blocking the smell from coming up through those holes with your paper towels.

Remember the fix I suggested before, no tile tear out but instead build a new barrier from above.

 

[Kingsotall]

So there is a definite seal from sewer gases via the pipe. It is coming from somewhere else. The nose knows in this instance.

 

[KCEdds]

Thanks to everyone who offered suggestions to this post. I hired a tile guy to rip up the floor of the shower and the concrete sub-flooring was just crumbling and filled with mold. He removed everything and we even replaced the top part of the drain (but not the trap because that would have required going up through the living room ceiling below).

The reason for replacing the top part of the drain was because the screw hole that held on the drain cover was cracked and that was possibly allowing water to seep outside of the drain onto the concrete below.

But I also noticed that there was a brown film inside the drain that I could scrape off with a Q-tip. I'm wondering if that was mold and if mold has grown down into the trap? I'd hate to spend all that money to replace the trap and go through the ceiling below if it was unnecessary. Is there a liquid cleaning product that I can pour down into the trap to kill any potential mold?

Thanks!