Getting rid of fungshrooms.

November 6, 2007 9:04 AM

There's a mushroom growing from the grout under our bath tub. How do I effectively get rid of it (are there fungicides I can use?) and how can we prevent it from coming back?

How did it get to be there in the first place? I imagine it has to do with water splashing out of the tub when people take a shower, but there's got to be more to it than that. Our bathroom is not particularly dirty, either. We keep it quite clean.

(Google has revealed other people with "fungshrooms" but no clear steps on getting rid of them)

posted by DrSkrud to Home & Garden (12 answers total)

When this happened to my folks, it meant there was a leak in the bathroom. Specifically, the leak was in the overflow from the shower/tub set up, which was trickling down through the walls and floor. Not so much that there was a leak in the ceiling downstairs, but enough to keep the wood and underlay moist and perfect for growing little 'shrooms.

Please don't just spray fungicide and hope it goes away. Have this looked at ASAP.
posted by LN at 9:10 AM on November 6, 2007

Mushrooms like to eat lignin and cellulose- which are not generally found in grout. I agree with LN that this may be a larger problem, and that you might want to check out the underside of your bathroom.
posted by oneirodynia at 9:30 AM on November 6, 2007

LN's got the typical scenario. We got the occasional mushroom growing out of the grout in my SO's old bathroom for the same reason.
posted by desuetude at 9:34 AM on November 6, 2007

Oh, and dousing with bleachy things will keep it at bay for awhile, but is not a real fix. (The landlord never got around to addressing it, so we were stuck with those temporary measures.)
posted by desuetude at 9:35 AM on November 6, 2007

I can't explain the biology, but there's a crack in my concrete basement floor that occasionally hosts mushrooms even with no cellulose source nearby. That said, I would worry about a leak. The joint between the tub and floor tile shouldn't be grouted anyhow (though it often is). It should be caulked. Grout in such a corner almost always cracks and admits water.
posted by jon1270 at 9:38 AM on November 6, 2007

A mushroom is the fruiting body created by a mycelium. If it's prosperous enough to create a fruiting body, it means it's gotten into something big and seriously degraded it -- probably wood, possibly load bearing.

As others have said, this is a symptom of something much, much worse. The mushroom is the tip of a much bigger iceberg, and you need to find out what it's growing in, and why.
posted by Steven C. Den Beste at 9:40 AM on November 6, 2007

This happened in my first apartment when I was 17 in Florida. This creepy little long stemmed mushroom grew up and out 3-4 inches from the shower wall. It freaked us out because it would -bleed-.

We would wear gloves and tear it out every day, but it kept growing back. Finally, being brilliant 17 year-olds, we took a lighter and Lysol to it. We sprayed fire right into the crack. It never grew again.

I haven't thought about it in years, but now that I do, chances are that it was the Lysol's antifungal properties, rather than fire that did it in.
posted by Cat Pie Hurts at 9:45 AM on November 6, 2007 [1 favorite]

I can't explain the biology, but there's a crack in my concrete basement floor that occasionally hosts mushrooms even with no cellulose source nearby.

It's true that those things aren't the only source of fixed carbon for fungi, but there's a very good chance that mushrooms in your house are fruiting from mycelium feeding on wood.
posted by oneirodynia at 10:52 AM on November 6, 2007

What everyone else said: mushrooms in the bathroom are usually a symptom of some serious damp problems, probably due to a leak somewhere in the fittings. We recently had the same issue with a shower, and it wasn't pretty when the tiles came off. We had to replace a few square feet of wall before re-tiling, but luckily there was no terminal damage to the floorboards. If it's your property, get a professional opinion and get it fixed, you really don't want rot to set in, that can be a real pain to get rid of.
posted by tomsk at 12:29 PM on November 6, 2007

Call your landlord now.

A friend of mine in Manhattan had a lot of issues as the result of things like this - there was a leak. First there was some ceiling discoloration, then the entire ceiling FELL IN, then they started getting MUSHROOMS in the walls.

There was a great deal of trouble, and my friend ended up moving out and threatening to take the landlord to court for trying to get back rent for the four months they had no ceiling, a leak, and fungi blooming in the bathroom.
posted by mephron at 1:01 PM on November 6, 2007

Fungal spores can be very hazardous to your health. If it is in a fruiting stage, call an expert. Don't muck around with fungi in your house. Get it professionally removed. Some can be killed off with the right combination of heat and fungicide, but you really want to have this thing taken care of by someone who knows what to do.
posted by caution live frogs at 1:57 PM on November 6, 2007

Water splashing from when people take showers will keep a mushroom alive quite nicely. Spores might have come in on your shoes.

I used to have a mushroom growing between the stick-on floor tiles in my bathroom. I told the landlord about it, and he put in a new vinyl floor while I was out of town. Lived in the place a few years after that without any other problems.

There are ways to kill off the mushroom, but the larger problem is that water is getting in somewhere it shouldn't be. The mushroom is a sign that this needs to be fixed.
posted by yohko at 5:51 PM on November 6, 2007