Hi all,
Thought I’d throw this out there to all those in the Taunton brain trust and see what comes back. Got a friendly call from a customer today, built two additions for him 6 years ago. One ( family room ) on one end of the house, one ( 2 car garage w/ master bed/ master bath above). He’s about to have a few rooms painted in both the original house and the addition, and it appears that there is ” something ” on the walls of the new sections of the house. I haven’t been over to look at it yet, but it’s been described as either dust or light mildew at the line of the ceiling/wall intersection, but on closer examination, he says there are also spots at the screws holding the sheetrock up! He says that with a step ladder, he went up and the ” dust” or whatever it is wipes right off.His painter feels it might be a lack of ventilation problem.( He hired his own painter when I built the add., I oversaw the rest .Same guy doing current work)
A few details: There was a major moisture issue with the original house before I did the add. Bath fan ” vented ” into attic, no soff vent, no ridge vent etc. Rectified all issues w/ soff vent , cut in ridge vent on old ( new all vented as well obv.) no signs of mildew or any discoloration in attic of new sections of house. Additions were dry to weather for a good month before insulation, proper vent used in rafter bays ( no cathedrals). I’m inclined to lean towards a Board/ plaster/ or paint issue, mainly since if it were a ventilation issue, wouldn’t there be some evidence of same syptoms in old part of the house? 25 years, first time I’ve heard of this. Any advice appreciated.
Bing
P.S. House in S.Eastern Mass.
Replies
Bing,
Probably just dirt. Do they burn candles ?? You should see the drywall on my finished office at my machine shop. Every screw or nail depression looks like you have painted it black :) Wipe it off and its back in a month or so. Nice clean environment we work in :(
Bill Koustenis
Advanced Automotive Machine
Waldorf Md
Candles was the first question I asked. Says they " never " burn em.
If they have forced air heat, how old is their furnace? If it is putting out black stuff then it would look the same as problems from candles. Maybe a furnace check and a vacuum of the vents is in order?
I second the vote for candles.
I've seen this type of thing several times. The scew heads conduct cold to the drywall face, causing the smallest amount of condensation. Any airbourne dirt or dust sticks to the spot, showing the screw locations. Not so noticable in a clean home, so the candle theory stands up. Frequent painting also helps, for some reason more coats seems to alieviate the problem. Perhaps more paint lowers the porusity of the wall, thus the condensation would evaporate quickly. On old wood lathe and plaster homes, I've been able to see not only the studs, but each lathe as well.
Karp's right - that condition typically has to do with the thrermal bridging. I've seen commercial construction with steel studs on the poorly insulated exterior walls where you could see every stud, brace, etc in a light black 'shadow' on a white wall.
Sounds like the black staining at the wall/ceiling intersection might be more related to the former moisture problem.
Is this happening at the intersection of the gable end wall.
read through all the posts and agree with the burning something scenario. my father let a propane heater get low maybe empty on fuel and wick started burning. every nail in the sheetrock was black.
I gotta agree with Karp.
Normal dirt in the air is enough to leave a shadow on a screw.
It only appearing in the new section is not surprising.
Wash the walls (normal paint prep) and re-paint...buic
BUIC and Karp are right on.
My son rented a house that he and my other son and I had remodeled.
All the walls, especially nearer the ceiling, and absolutely in the bathroom, had dark spots on the drywall screws. In the bathroom it was the worst. I remember being in there during the winter, and the moisture content in the air was high.
The bathroom ceiling needed repainting, and all the exterior walls needed repainted when he moved out.
So, to reiterate, thermal bridging is the problem, with dust or soot collecting on the slightly cooler screw heads where moisture had condensed.
Bryan"Objects in mirror appear closer than they are."
Klakamp Construction, Findlay, Ohio
Thanks to all for thoughtful replies.
I'm inclined to agree on the condensation on the screw head theory, although I'm not sure why it's only hapnin' on the new part (s) of the house. I told the owner I'm inclined to think that fresh paint ( after a good wash ) will cure the problem if I'm right and it's just dust. I also think the additional layer of paint may break the difference in temp enough to make a dif. I think after reading your responses I will also mention the furnace aspect, although the heat is oil fired, it's forced hot water baseboard, so while an inefficient boiler could be burping up some soot, it's not blowing it around like it would be if it were FHA. At any rate, it can't hurt to mention it on the off chance that he changed oil companies or some such, and forgot to get his boiler cleaned this year, or whatever.
Thanks again'
Bing
Seems like a "sucking" problem. Older homes breathe. New buildings are tighter (more insulation, more weatherstripping, dual pane windows, etc.). You stated that this condition is at the new section/addition. Are the ducts modified for proper return and supply air changes? I have removed pictures from walls at new homes and found a dark (not a lighter) footprint. I blame it on the the house wrap (product or installation).
I'm not sure what ducts you're refering to; forced hot water heat, no ac at all.
Though soot will make it show up REALLY fast, the problem is actually due to that specific area being slightly colder than the surrounding area. This condenses a small amount of water vapor, which will then trap dust particles. Soot will make it stand out right away, but just general dirt will also appear.
Paint is not a good enough insulator, you will have to do something else to fix the problem.Rebuilding my home in Cypress, CA
Also a CRX fanatic!
If this is a correct guess, why only in the new part of the house? Why would the 1-1/4 sheetrock screws transfer cold thru a 2x4 wall that much more than the stud itself? I'm not disagreeing, but am trying to nail down a more specific cause/cure. Most of all, I'm wondering why it's happening on this particular house and none of the others I've built. (unless it is and no one has noticed it before.) I like mysteries in book form; on jobs not so much;)
Thanks again
Bing