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Stud and joist ghosting through drywall

Fbart's picture

A current customer has "ghosting" of studs, and ceiling joists showing through the paint on walls and ceiling.  She has asked me to investigate the cause of this.  I suspect that  part of the problem may be inadiquate venting of the attic ( there are two gable end vents, but no soffit vents).  I have not yet been in the attic to see if there is a vapor barrier, but if there is it is probably only craft paper on batt insulation.  There is blown in cellulose that we foound when soffits were removed in a kitchen remodel. 

Any ideas and suggestions are appreciated.


(post #69291, reply #1 of 4)

You may find heavy smokers in the house.

Maybe they often burn candles.

And you may find a problem with a vented appliance. Gas or propane.

Check those vents. This could be a health hazard. Ask Bob Walker about that...

The studs, and especially the nails/screws will attract the pollutants out of the air.

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(post #69291, reply #2 of 4)

As L noted, the carbon soot in the air from candles, smokers, and backdrafting combustioin devices or wood stoves can leave a residue that makes theis effect more noticeable, but it can be seen quite often even in houses heated with electric and no candle burners or smokers. but it has nothing to do with the venting situation.

What happens as the main cause is that the studs are a thermal bridge between in and outside temperatures. The stud wil be much cooler than the insualted space when winter temps get really cold. Then condensation makes the SR there damp and it grows mildew, which can be washed away, as can soot. It is the dampness that attracts the soot to stick there.

I have done away with this by installing a thermal break - faom panel baord that transitions across the surface of the studs. Needless to say, this is expensive and normally only a part of a total remodel since it requires teariong off th esheet rock or plaster.

on a more practical level, if they are not going to tear off the SR or siding, the surfaces need to be washed well with TSP and maybe Clorox weak in water and rinsed, then painted with a washable paint with mildewcide or fungicide additive. What this will do isto make it easier for them to wash in the future and it will reduce the amt of moisture that can penetrate the wallboard to foster the growth of the mildew.

But do spend time ascertaining their lifestyle. If no smoking or candles, and soot can easily wiped off the surfaces, the furnace must be in need of adjustment for the safety of the occupants.



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(post #69291, reply #4 of 4)

You hit the nail on the head as the culprit is lack of a thermal break. Around here it's real common in older houses where the insulation doesn't cover the top of the ceiling joist. In most cases adding blown in insulation over the joist solves the problem, the walls are a bit more difficult to remedy.

(post #69291, reply #3 of 4)

Google Home Energy magazine. They have free back issues on line, and this topic is covered.


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