[Pete's Painting]

did an estimate last weekend, the livingroom is an addition, cathedral ceilings, a few years old, everything is painted white.
On the walls there are black shadows outlining where the studs are, almost a perfect photo negative. Not every 4 feet where taped, but every 16 inches. What is it?
The black color made me think of mildew, but how and why? Didn't see any water stains.

any chance it's a recurring problem?

 

[vermontpainter]

What state are you in?

 

[Pete's Painting]

I'm in Mass Scott

 

[vermontpainter]

We get that sometimes here in Vermont, only more commonly on ceilings where you see the black shadows across the ceiling at each rafter location.

Its a function of heat loss from inside the house. Wood (rafters and studs) has no R-value. Heat loss from inside the house transfers through the wood and comes into contact with the cold sheathing on the other side of the framing and forms condensation. The condensation migrates from the the exterior side to the interior side, wicks its way through the drywall slowly over time and forms the subtle black mildew stains you see. Have you ever noticed on a chilly spring morning if you look at roofs early in the morning when there is frost on them that the frost has melted on each rafter and you can see the lines of the framing? This is whats happening.

Seeing it on wall studs would make me think its a function of heat loss at the top of wall and gravity is bringing the condensation down each stud bay. I have successfully 3-coat binned such staining and put two coats of paint over it. My parents bought a house with this problem 4 years ago and I did it at that time. I watch it like a hawk and no recurrence.

 

[timhag]

You may want to open up a small area where the black is and see what's going on behind. There may be a leak where only the studs are soaking up the moisture. Do this only if you think it may be mold.

 

[vermontpainter]

Tim

Did you read my damn post? :whistling2:

 

[timhag]

lol.....I was in the middle of posting and got delayed by the door bell. Came back, posted, and there you were.

 

[NEPS.US]

lol.....I was in the middle of posting and got delayed by the door bell. Came back, posted, and there you were.

Domino's ....fatty?

 

[MAK-Deco]

Domino's ....fatty?

:blink:

 

[timhag]

Domino's ....fatty?

LOL....Only if.........:yes:

 

[MAK-Deco]

You can't have Pizza tonight you have your weigh in!

 

[timhag]

You can't have Pizza tonight you have your weigh in!

No Pizza for me tonight. Had some oganic pasta with organic garlic bread.

 

[NEPS.US]

hahaha I'm eating a bowl of popcorn and drinking a Sam Adams right now

 

[MAK-Deco]

hahaha I'm eating a bowl of popcorn and drinking a Sam Adams right now

NEPS did you see my post about the Sam Adams recall??

 

[NEPS.US]

NEPS did you see my post about the Sam Adams recall??

crap.....no

 

[NEPS.US]

NEPS did you see my post about the Sam Adams recall??

OUCH ....I'm rich bitch!!!!!!!! see you painters ....I'm outta here!!!!!

 

[ogre]

The shadows could be soot from burning candles. I have done a few jobs where it was dark around joists and every nail in the ceiling. In all cases people burned candles all the time. Good primer and paint took care of it.
Good luck, Mike

 

[alpinecrick]

did an estimate last weekend, the livingroom is an addition, cathedral ceilings, a few years old, everything is painted white.
On the walls there are black shadows outlining where the studs are, almost a perfect photo negative. Not every 4 feet where taped, but every 16 inches. What is it?
The black color made me think of mildew, but how and why? Didn't see any water stains.

any chance it's a recurring problem?

It is quite common out here where a wood burning stove or wood/gas fireplace is in use--just bid a house like that today with a fireplace in the master bedroom and a tall vaulted ceiling--could see where every rafter was.

Using a paint with a sheen (satin, S/G, etc) no prep is necessary, with flat paint, a stain blocker primer like latex Kilz would be a safe bet.

Like Vermont said, it is the heat loss and/or moisture diferential--but studs and rafters DO have a R-value--just not as high as the well insulated space between studs/rafters.

This is one reason the use of a barrier such as Tyvek wrap has gained acceptance today. It acts as a "break" against moisture and heat transfer.


Casey

 

[slickshift]

Hey Pete...how is the house heated?
Electric baseboard?
Forced air oil furnace?

If that's blow-back from an oil furnace episode, it's gonna be a wicket pissah to clean/cover
It could have been from years ago and still be there
It won't clean...as all cleaners just seem to make it mad
It will bleed through everything except BIN

I'm not saying it couldn't be them not trimming their candle wicks, or from a wood stove
I'm just saying it could be blow-back too, and treating blow-back lightly will not bite you in the butt, it will bite your butt clean off

 

[slickshift]

...a stain blocker primer like latex Kilz would be a safe bet.

That's the funniest thing I've read all week
I wouldn't bet on latex Kilz to block a mosquito fart
It's got great odds in the "Fall Off The Wall For No Particular Reason Championship Playoffs" though