interior black spots ???

[steve]

Maybe some can help me here. I have a home that was built in 1961 and I have found black spots while painting the interior. The spots are approx. 1" in diameter and are very hard. I tried to paint over them and they bleed back thru the paint. The strange part is that if I try to use a scraper to remove them they appear to smoke. The same also happens if I use a cleaner such as 409. Looks like some sort of chemical reaction. I have only found 4 or 5 of the spots in different areas of the house ???? Any ideas what it could be ?? . I first thought perhaps some sort of flux used by a plumber or something but some of the spots are in closets with no plumbing anywhere close. Thanks for any ideas. Steve / NE Texas.

[roger61611]

mold ? i'd dig thru all the way to see what's going on.

[Joseph Meehan]

Sounds like mold to me. Use bleach to kill it and a sealer to seal it, then paint it. If there is a lot on a wall, I would replace that panel of drywall. If you have someone who might be mold sensitive, that might be a good idea anyway and it is possible you have a leak of some time there creating a moisture problem and that should be addressed first.

[steve]

I'm postive it's not mold. It looks like a hard grease spot or something petroleum based. It looks like maybe it dripped down the wall during building ? I can spray 409 or windex on the spot and it has a chemical reaction and gives off a few puffs of smoke ???? I've painted the entire house and found 4 or 5 of these spots. I've used rubber gloves and a scraper to remove them and then painted over them. There not a problem now but I still can't figure out what they were. Thanks , Steve

[wkearney99]

Your local government might have some sort of hazardous materials testing service. Or a local college. Cut a chunk of it out and have it tested.

[Norminn]

If they are along joints, mebbe they are corroded nail heads?

Can't imagine what would smoke if 409 or Windex were applied. Perhaps it is mold that is dry and dusty. There are mushrooms that look like they smoke when ruptured because they give off fine spores. I would wipe the spots with bleach, cut out surface, patch with spackle or joint compound, prime, paint.

[steve]

I did some looking and found another spot. I am almost postive it's something petroleum based. The spots are very hard on the outside and I have to scrape them off. I'm sure it's not a mold. I took a picture of a spot here:

is against a door jam in a closet. I sprayed the 409 on it and there's a chemical reaction but I could not get a picture of that. Here's another place in the same closet: the other spots have been on the sheetrock, this one is on the mortar side of a fireplace. The only places I have found these are in closets. Nothing in the closets except for a light. And I found three spots in a utility closet where there is a lot of plumbing. It looks a lot like creosote ???? I may try to see if I can get a piece tested just to see what it is. Thanks, Steve

[rosie read n' post]

steve, is there perhaps a live wire behind the drywall?

[rosie read n' post]

steve, is this dripping tar and nicotine?

[steve]

No wires behind a couple of the areas. And the house was built by a doctor and never smoked in. I have a friend who says he can have it tested. I'll let you know what he finds. Thanks for all the help. Steve

[ameijers]

Looks like construction adhesive in one picture, and splattered stain in another. Did the previous owner have any windows or trim redone in those rooms, or maybe refinish some now-gone furniture there? If all these backed up to a fireplace, I'd say creosote.

If they scrape off, and a test hole in the surface below doesn't look like they came through the wall, I wouldn't lose any sleep over it.

aem sends....