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NY Good Questions: What Could These Black Dots Be?

1.18dots.jpgHello AT,

Recently, I noticed these black dots on my ceiling.

They are all the same size, perfect circles, and equally separated.

I was thinking that it could be mold, but the shape is too perfect.

I tried to clean it with bleach but I just wound up smudging the black stuff.

What do you think it is? Thanks! Heather

(Note: Include a pic of your problem and your question gets posted first.)

1.18dots2.jpg

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Comments (19)

perhaps moisture is removing a coating from the sheetrock screws?

posted by bramasoleiowa on 2008-01-18 13:05:07
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yeah, like bramasoleiowa, I think it looks like nails in studs rusting...

posted by ChristineBadina on 2008-01-18 13:08:23
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I'm guessing it's corrosion from nails or screws that hold up the gypsum on your ceiling. (those fasteners are almost always 16" or 24" apart, along the joists of the floor above.) If you're on the top floor, the fasteners might be acting like a cold bridge between the cold air outside and the warm air inside and getting condensation on them. If you're not on the top floor, it might be moisture from somewhere else, like improperly insulated plumbing lines.

Not really sure what to do about this, but I'm sure someone can help you out!

posted by bloo_mountain on 2008-01-18 13:09:45
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It's most likely the drywall screws popping out of the studs, which explains why the dots are evenly spaced. I don't know why they are black, but it might be due to moisture in the ceiling, which would also explain why the screw are popping out. What is above your ceiling – another living space, a roof, or attic? I'd call in a professional to deal with the moisture first, before repairing the ceiling.

posted by Snoozy on 2008-01-18 13:09:53
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I've also heard of screw paint bleeding through if not properly primed before painting -- so it could possibly not be moisture related.

posted by jayme on 2008-01-18 13:23:15
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It is alltrue above mentioned screws or nails,it can be also be an old electrical wire nailed to the ceiling boards,sheet rocks or plywood...., just choose one and dig in and you will find out,make sure you are doing it with insulated screwdriver so if it is electrical wire,you are not zapped...

posted by edesign on 2008-01-18 13:26:28
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MOLD

posted by spanishfish on 2008-01-18 13:39:05
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It seems like it could be soot collecting on the nail head spots. How is your heating system? Do you smell anything different? Did you have a small fire or are you burning a fire in a fireplace? Do you burn a lot of candles that produce smoke?

posted by loridilo on 2008-01-18 13:47:49
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Spanishfish hit it . . . mold!

posted by ChrisToronto on 2008-01-18 13:58:18
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I think those are screw heads, but a coat of heavy-duty primer (not the latex stuff) might cover them up.

posted by Fingernail on 2008-01-18 13:58:58
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I have something very similar in my apartment and I think they are screw heads. It's just too uniform to be mold. I started noticing them around the time there was construction going on next door. It is a bit worrisome about how structurally sound my building is now.

posted by malinda on 2008-01-18 14:13:46
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The first picture looks like screws but the second photo looks like mold...maybe everyone is right.

posted by metalfingers on 2008-01-18 14:33:35
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I think it is mold that has made its way through the thinner/weaker part of the drywall where you find the nail/screw holes. That is why it is focused and uniform...

posted by aaron on 2008-01-18 14:37:22
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hm. i say you try going out and having a few margaritas followed by a session of dancing and socializing and you won't notice them at all!

posted by jeannie on 2008-01-18 15:23:34
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I am on the 2nd floor and there is an apartment above me. It's a condo building but I rent from the owner of the condo. Should I contact the person I rent from or the building owners?

The 2nd picture shows what I did when I tried to clean it with bleach. It just wound up pushing the black stuff all around and now it looks like a mess.

posted by heather lauren on 2008-01-18 16:25:50
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I would say screws but sometimes...depending on the age of the property it's not screws but nails which are more apt to "pull" out of the drywall and studs.

posted by Patrickinchicago on 2008-01-18 19:10:12
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bloo's got the right idea. The metal of the nails or screws that fasten your drywall to the studs is getting cold enough to attract condensation (just like moisture condenses on a glass of ice water). Are we looking at the underside of a ceiling, attic, or other unheated space?

Anyway, moisture is condensing on those metal fasteners, and the black spots you're seeing is most likely mold, though I suppose it could also be something like soot getting trapped in the spots of moisture.

Solutions? Check that your heating/air-conditioning system is doing its job properly and drawing excessive moisture from the air. Insulate the dead space above your ceiling.

posted by Bruised on 2008-01-18 20:11:49
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as a realtor, i think you should talk to both parties and get an inspection done. if it is mold then it will affect everyone.

posted by Joan Vignocchi on 2008-01-19 02:31:23
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Heather, you say you rent from the owner of the condo, then you ask if you should contact the owner or the person you rent from? Aren't they the same person?

Anyway, contact whoever you send your rent money to and request (then demand) that it be looked at. I would start by digging at the spots to see what is underneath. If its a rusty nail/screw, you'll find it. Then, someone needs to fix the moisture problem, or it will just come back. If the whole ceiling cavity is infested with so much mold that it's growing through the screw holes (if that is even possible), then I'd move, pronto.

posted by Jon_B on 2008-01-21 10:13:04
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