got a call today from a very fussy customer of mine.He tells me hes seeing darkish lines on his first floor ceiling.I have not had oppertunity to see the problem yet. I wanted to throw it out there,cause I have never seen such a problem before.He says they are first floor only;a few feet out from the walls;and by the sounds of it,either following the joists or strapping.
The house is a 20 +/- yr.old cape style house in the northeast.Possibly poor insualation plugs causing condensation???Any other ideas???
Replies
Either someone's a smoker or he's been burning candles.
Fireplace have poor draft? Furnace issues? Mice playing with matches? Mike L.
nope,no smokers or candle burners!O'k.maybe a boiler issue,but why is it showing up at joist locations only?first floor only?and just a few feet out from outside walls???
Something is generating soot in that room. What is above this room, a 2nd floor or a roof?
So convenient a thing it is to be a reasonable Creature, since it enables one to find or make a Reason for everything one has a mind to do. --Benjamin Franklin
It is common to have this problem with no source of soot, though that does make it worse or more obvious sometimes.
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I don't believe that it's (usually) caused by condensation, but rather the lower temp reduces Brownian motion near the surface, allowing dust (and especially soot) particles to cling by static electricity. Normally the particles would adhere to the ceiling anyway, but spread uniformly across it, so they wouldn't be noticed.
So convenient a thing it is to be a reasonable Creature, since it enables one to find or make a Reason for everything one has a mind to do. --Benjamin Franklin
I don't know what Brownian motion is, but I know that the problem can be fixed by adding proper insulation and that if all you do is wash and paint, the probelm will recurr whether there is soot present or not.
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Believe what you want, but when warm humid air hits my cold beer,condensation forms. Of course it could be bownian motion, but static electricity is not something I normally notice in my ceiling joists or my beer.
That's why your beer doesn't stick to the ceiling.
So convenient a thing it is to be a reasonable Creature, since it enables one to find or make a Reason for everything one has a mind to do. --Benjamin Franklin
Why only a few feet out?
Because that is the extent of the cold infiltrating the joist to cause condensation, which is trapping whatever airborn crap that is causing the marks on the ceiling.
I would bet that it's the joists (or strapping) "ghosting" thru the drywall. In a cold climate, the joists act as thermal bridges. A thermal bridge conducts heat faster than the adjacent (insulated) joist bays so the drywall will be slightly cooler at the joists than between them. Moisture in the air will condense at the cooler locations. Add in some dirty air (smoking, candles, etc) and poor circulation, and you'll see dark lines.
Another possibility is that the ceiling drywall is sagging slightly. My sister's first house had 1/2" ceiling sheetrock on 24" centers (yes, it was a cheap tract house - lol). It was very well insulated and the previous owners had used the attic for storage. The weight of the "junk" had compressed the insulation which had bowed the sheetrock. When I first saw it, I almost choked. The ceiling had very visible waves. - lol
One possible and simple solution to your problem may be to check the air circulation in the room. If they're leaving a door closed most of the time, it may be preventing air flow back to the cold air return.
My brother in law has the same problem in their kitchen. The house is about 30 years old. The drywall is not sagging or anything like that. There is an attic above the kitchen. I noticed it the first time I walked into their place but didn't mention anything to them. Otherwise they would have ask me if I could fix it for them.
Martin
that happened in my sister's house. problem was her furnace
h/w heat not fha.but they do have central a/c....so are we leaning toward a poorly vented/drafted boiler???possibly a chimney cleaning?I understand the concept of the thermal bridging;but why are these marks showing up mostly in only one room of a 3000 sq.ft. house?Thanx for all the great input!keepum comin!!!
The one room has colder ceilings and/or more soot in the air.
So convenient a thing it is to be a reasonable Creature, since it enables one to find or make a Reason for everything one has a mind to do. --Benjamin Franklin
BTW, you still haven't said what's above this room.
So convenient a thing it is to be a reasonable Creature, since it enables one to find or make a Reason for everything one has a mind to do. --Benjamin Franklin
but why are these marks showing up mostly in only one room of a 3000 sq.ft. house?
Because the other rooms don't have the same unique condition that one does? Your lucky in a way, because the problem is localized which should make it easier to determine what makes that 1 room different then the rest.
Furnace might have put some soot in the air, but the problem is the lack of adequate insulation that causes the condensation to allow the soot to adhere in specific locations
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I had the same problem when I first bought my house. It had an old oil burning boiler with issues. An un-insulated rim joist allowed cold air to get into the bays. The joists acted as a thermal bridge transferring the chill to the board/plaster. Under other circumstances, the condensation would never have even been noticeable but with the boiler pumping a bit of soot into the air it became very noticeable. I agree with the other posters... somethings probably creating soot. Could be as simple as not using an exhaust fan while cooking or a poorly drafting fireplace, candles, incense, etc.
EDIT: and yes... it only occured in one particular room for whatever reason. Just the right mix of conditions I assume. We've since replaced the boiler (and the rest of the house for that matter LOL) and the problem has not reappeared on the new paint job. Never did get to add that insulation while I had the roof off though.
Edited 4/29/2007 11:29 am ET by dieselpig
"An un-insulated rim joist allowed cold air to get into the bays"You've got it!
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Glad I dropped in over here today. I have a bedroom with heavy ghosting on one exterior wall. It was that way when I bought the house, and the room has gloss white paint on the wall with the ghosting.
I have been holding off repainting the room until I knew what was going on. It isn't anything I've ever seen before, but I spent the last thirty years in Vegas, and just moved somewhere with four seasons, and real winters, so thermal bridging with the stud cold wasn't an issue before.
So, I surmise, that if I repaint with a semigloss in a medium tone, the problem shouldn't reoccur. I don't smoke or burn candles, and due to allergies I run hepa filters constantly in every room. (There isn't central heating so there is no other filter system.) Or, would a darker tone be better? I haven't even started to think about decorating this room other than the furniture will be walnut, with white oak that has a light walnut stain.
For a complete description of "ghosting" read this article from building science:
http://www.buildingscience.com/documents/digests/bsd-150-black-stains-on-carpets-and-ghosting-of-framing/view?searchterm=ghosting
Richard P. Feynman
The condensation can attract dust which feeds mildew to stain the surface. Very classic description.
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