I good client whose house I renovated in 1999 has had some weird “eruptions” on a few of the sheets of drywall. They appeared slowly over the last 5 years, and manifest as a bump, then a “+” shaped split up through the paint, then a tiny brown stain (it’s a bathroom with a big shower).
Today I cut them all out, and found little crumbly black bits at the centers, about the size of 1/4 to 1/3 of a grain of rice – they are faintly magnetic.
They were all below the paper, not in the mud. No kidding, I cut 100 little craters out of one big bathroom (10 X 12 X 15′ at the peak).
I’m confident these repairs won’t come back, having cut down 1/4-3/8″; to pure white gypsum.
But, what in the world is the black stuff? My drywall supplier came out to look before I started to cut them out, and said he had no idea . . .
Lookin’ for ideas –
Forrest
Replies
poltergiest...............
Life is not a journey to the grave with the intention of arriving safely in a pretty and well preserved body, but rather to skid in broadside, thoroughly used up, totally worn out, and loudly proclaiming
WOW!!! What a Ride!
Forget the primal scream, just ROAR!!!
Off hand I'd say something got into the slurry when they poured it out to make the drywall--pieces of the machinery or something got ground up in the gypsum or fell on it while it was on the conveyor. You might try contacting the manufacturer; if it happened there, (and I cannot imagine where else these specks would have come from) you probably aren't the only one who's had trouble.
I'd agree with that.
Some power plants use limestone in their flue gas desulphurization (FGD) units, and the "dirty" limestone is usually sold to gypsum companies....that makes me wonder if there were iron particles, or other "heavy metals" in the wallboard, and they gradually absorbed enough moisture to rust; once the rust starts, the iron expands...and maybe the wallboard was made with gypsum that came from an FGD plant....do you know what brand of wallboard?
Maybe it's because it's a bathroom, and the moisture level is high enough to migrate into the gypsum....interesting to see if it's common or not.
"Iron" or other ferrous substance is a heavy metal now? Let me go over that old text book from chemistry again with the periodic table in it. Hmmm! Tyr
Iron" or other ferrous substance is a heavy metal now? Let me go over that old text book from chemistry again with the periodic table in it. Hmmm! Tyr
Okay, to be grammatically correct, it should have read:
iron, or other, "heavy," metals.
Is that better?
Cool. I get enough crap about the "environment" without someone scanning these forums and "learning" their house is full of "heavy metals". Thanks, Tyr
Thanks for the quick responses - the recovered flue gas seems a fit, because the particles are crumbly, not like iron, but the are magnetic.
My supplier (Eastern) got drywall from three different manufacturers during the time I hung that rock, and the only was to determine which is correct would be to open up a wall and look for a date code and info.
Forrest
It's in the Bathroom?
Along the exterior wall?
Did you install a vapor barrier BEFORE to installed the GWB?
Did you prime the walls prior to painting?
If the iron particles are the culprit, they would need to have engaged in some sort of reaction - by coming into contact with moisture.
Starting to get the picture?
That's my analysis.
Frankie
There he goes—one of God's own prototypes—a high powered mutant of some kind never even considered for mass production. Too weird to live and too rare to die.
—Hunter S. Thompson
from Fear And Loathing In Las Vegas
Interior and exterior walls seemingly the same result; vapor barrier on the insulation batts all around (the whole bathroom is insulated on all sides). PVA primer; two coats of SW.
Some of the eruptions are on an interior wall in an adjoining room, near an interior door to a hall - no moisture nearby.
Only a few sheets have acne, but those that do have 5-25 of them.
Forrest