That was mold ... right?

September 28, 2009 8:02 AM

My apartment leaked, mold grew on the walls, and the maintenance guy just bleached off the outer layer ... right?

Last week, my apartment leaked, and the walls got stained, as such.

This weekend, little black spots started popping up all over the place, as such.

Then the maintenance guys came in this morning to spray a cocktail of Clorox and Tilex, in which they dissolved some kind of "pill." This made all of the stains and spots instantaneously disappear, as such.

The maintenance guy said that there was never any mold -- just "hard water" stains -- and that residents tended to overreact to things that looked like mold. I am skeptical.

Am I correct in thinking that there was mold, and that they just bleached the hell out of the outer layer so I'd think everything was back to normal? Or were those spots indeed something benign?

posted by SpringAquifer to home & garden (9 comments total)

that's mold. can't speak for what's inside the walls.
posted by sarelicar at 8:04 AM on September 28

If those are "hard water stains," I'd stop drinking the tap water.
posted by Houstonian at 8:10 AM on September 28

That was mold.

Now, if the source of the water was dealt with (leak fixed) and everything is dried, out, your landlord may get away with this approach. If the black spots come back, that is bad news, esp since as of now, you have no idea of what type of mold it is. Stachybotrys can look like that, as can more benign types of mold.

Keep an eye on it, and, if I were you, I would get a bulk sample (the spot and some of the underlayer) of any spots that return and get it independently analyzed. Memail me if you need more info. . .this stuff is part of my job.
posted by Danf at 8:16 AM on September 28 [1 favorite]

Americans are particularly batshit insane about mould, it must be said. I'm not saying you are, I'm just alerting you may be a little culturally sensitive to this issue, particularly after all the post-Katerina press (where that situation was legitimately very serious.) But not all mould or mildew is necessarily a red alert issue. We bought a house plagued with mold because it's 125 years old and the house was unheated and thus, damp. None of the mold was toxic, and all of it was eradicated by bleach.

If you had water seepage, that's enough for a little colony to form. Mold is everywhere in the air at low levels, and those little black spots form very readily. You cannot and IMHO should not assume black spots indicate an underlying cavity issue.

Bleach and Tilex should be sufficient to kill and "cure" it - a bleach solution is what the CDC suggests, so this isn't some silly home remedy for cancer. If the water stains are dry and the spots do not return, I would assume the issue has been resolved.

FWIW we have TONS of these on our bathroom ceiling due to poor airflow in a naturally damp environment. We did a surface clean and lived with it for a year. We just this morning began a bathroom renovation. The contractor took down the ceiling board and indeed - spots on the exterior where we saw it in the bathroom; no spots on the reverse; no mould in the ceiling cavity.

Don't assume the worse. If it does not return, I'd assume the effective treatment was in fact effective.
posted by DarlingBri at 8:19 AM on September 28

That probably was mold, but depending on circumstances, what the guy did may not have been totally inadequate.

If the leak was a one-time thing (and not the continual and ongoing dampness you'd get from climate or in a bathroom) and you got a little mold, killed it, and are now keeping the humidity low, that ought to be fine.

Mold hurts you in two ways: when growing, mold gives off spores, which are respiratory irritants. In addition, the mold itself can also be irritating if you disturb it. Removing mold is much like removing asbestos, when done correctly. And like asbestos, if it's not hurting anything where it is, it can be better to just leave it alone (provided it's dead/inactive) than try to remove it and release it into the air.

Most mold goes inactive once the humidity is below about 45-50% RH. As long as you don't get any more water, and you don't disturb the inactive mold in the walls, I think you're probably fine. Nor do I think that the building owner has a responsibility to do a full mold-abatement (which involves having guys in bunny suits gut part of the apartment) if there isn't a compelling reason.

If you smell mold or have reason to believe that you're being affected by mold spores, you could probably press for a mold-spore analysis. The way you tell whether formal mold abatement is necessary (and whether it was successful) is via airborne spore tests. Basically, someone will use a vacuum-cleaner thingy to pull a known quantity of air through a filter, in several parts of the building. Generally once near the suspected mold, once elsewhere in the building in an unaffected area, and once outside. There are standards for how much higher the "indoor, affected" area ought to be from the "indoor, unaffected" and "outdoor" samples.

But if you don't smell mold and aren't having any allergic/respiratory issues, I wouldn't worry too much about it. You probably had mold, and it's now either dead or inactive somewhere in the walls. As long as the humidity stays low and you don't have another leak, and it was fixed promptly, I'm not sure I would do anything. (And if you do get some odor, the first thing I'd do is ask for the room to be re-primed and re-painted.)

I'm writing this from a house that had a serious mold problem when we moved it. Although we had as much of the mold physically removed as possible, a lot of it was on the foundation and there aren't a lot of practical ways to remove it (you can do sandblasting or shotblasting but they're extremely expensive). So eventually, we just had someone paint over it with very heavy, oil-based paint designed to encapsulate it, after spraying it with other chemicals to kill it. I call it the "Chernobyl method." Sometimes it's less dangerous to just encapsulate something permanently than to try and mess around with it.
posted by Kadin2048 at 8:20 AM on September 28

I'd say he's wrong about it being hard water staining, but he's right that many people overreact to mold. Mildew isn't anthrax.

What leaked? Is this an interior wall, moistened by a plumbing failure that has since been fixed? If so, the wall may be hollow and fairly quick to dry out and become a non-issue. However, if it's an exterior wall that's now full of damp insulation which will take a long time to dry out, more drastic measures might be in order. In any case, the most important thing is to make sure the interior of the wall is thoroughly dry. Until that is achieved, no topical remedy is going to be effective for long.
posted by jon1270 at 8:23 AM on September 28

Yeah, I'm not overly concerned about the mold, now that it's all on the inside or other side of the wall. Though, the water actually leaked through the wall, seeping out of cracks in the paint, from rainwater puddles in utility closets and walkways above and next to me, so I'm pretty convinced there's a huge mess on the inside that I can't see.

I suppose this question mostly came about as a result of my disbelief when the maintenance guy insisted that it was just "hard water."

Thanks, everybody!
posted by SpringAquifer at 8:30 AM on September 28

Bleach kills mold really well. Make sure the place is really well ventilated for a couple of days. The maintenance guy is an idiot not well-informed. Tell him you need them to provide you with a dehumidifier for a couple of weeks to be certain the dampness is completely gone.
posted by theora55 at 8:39 AM on September 28

I lived in a house that was built on a lot slightly below street level, and it rained a lot in the winter. To save money I tried not to turn on the heat in one of the rooms at ground level, and we developed a mold infestation in one corner of the room. We turned on the heat, and it went away.

However, we soon moved - I couldn't handle living in a house that was that damp, all of the time. I didn't want to think about what was going on inside the walls.
posted by KokuRyu at 9:08 AM on September 28