smoke or mold?

[Robert A. Jack]

The home is a modular ranch built in 1985. Very heavy smokers. Well insulated attic with large gable and ridge vents and metal roof. The plywood sheething was black as shown. Could this be caused by excessive cigarette smoke? I question mold because of the good venting. The interior of the home was yellow with nicotine.

[Stephen W. Stanczyk]

That appears to be a vent from a bathroom or kitchen fan. My bet is bathroom. It also appears to be newer. My guess is the bathroom fan emptied into the attic in this location for years until the last sale/inspection when this was installed. Pretty small picture to really get a good look.

[Michael W. Gault]

Moist air from the bathroom exhaust vent and a hot roof (metal likely not insulated well from the decking) kinda 'scorched' it mayhap?

[relliott]

used my magnifier and from what I see that is not from smoke.
My guess is the underlayment had a moisture problem from that vent not flashed properly.
Were u able to get a moisture reading?

[Kenton H. Shepard, CMI]

Hot air full of moisture hits the underside of the cold (Vermont) roof. Moisture condenses and wood gets soaked. Microbial growth.

Decay fungi, moderate decay of roof sheathing. Sheathing has probably lost 35% strength, maybe more.

[relliott]

Good theory

[Robert A. Jack]

Moisture maybe but the bath fan had been disconnected ans covered. The nails sticking into the roof sheeting were not rusted, signs of moisture. Didn't take a moisture reading. Thanks to all for the good comments.

[msylvester]

Looks like mold to me, probably a pen-asp or cladosporium.

[Mario A. Kyriacou, CHI]

Originally Posted by rjack1

The home is a modular ranch built in 1985. Very heavy smokers. Well insulated attic with large gable and ridge vents and metal roof. The plywood sheething was black as shown. Could this be caused by excessive cigarette smoke? I question mold because of the good venting. The interior of the home was yellow with nicotine.

Robert

Only one way to tell for sure, do a mold test. In this situation I would use a swab and send it to Pro-Lab. Results in 24Hrs.

[Brian A. MacNeish]

Originally Posted by rjack1

The home is a modular ranch built in 1985. Very heavy smokers. Well insulated attic with large gable and ridge vents and metal roof. The plywood sheething was black as shown. Could this be caused by excessive cigarette smoke? I question mold because of the good venting. The interior of the home was yellow with nicotine.

It's mold. Good venting does not ensure a dry attic!!!

See: http://www.cmhc-schl.gc.ca/en/co/mah...gemare_001.cfm

From the above:
What To Do About a Wet Attic

The usual response is to increase attic ventilation. This is the wrong approach. In some cases, adding ventilation will actually pull more moist house air up into the attic and make the problem worse. The best way to fix a wet attic is to stop air movement, or leaks, from the house. Once this is done, the existing ventilation is usually more than enough to keep the attic dry.

And from a 1980's article, Attic Ventilation and Airsealing, from the NY State Energy Research and Development Authority:

"In fact, there is no guarantee that providing a specified area of passive ventilation openings will yield some desired level of of ventilation"

[dpotts]

I agree Brian. Ventilate all you want but without preventing heat loss and air movement ..... But for the original question; that is mold or other fungi untill proven otherwise.
Recommend "further evaluation by qualified specialist".

[gporter]

Advise for mold testing to cover yourself.

[David P. Valley]

Do you think you can make that pic any smaller?

Looks like moisture accumulation which caused the mold looking build-up.

[Larry D. Kage]

Originally Posted by rjack1

The home is a modular ranch built in 1985. Very heavy smokers. Well insulated attic with large gable and ridge vents and metal roof. The plywood sheething was black as shown. Could this be caused by excessive cigarette smoke? I question mold because of the good venting. The interior of the home was yellow with nicotine.

Gable and ridge vent do not make good ventilation...air comes in the gable and out the ridge...nothing circulates down near the eave walls.

Still, it looks like evidence of condensation to me too.

[Dennis R. Goudreau]

Originally Posted by kshepard

Hot air full of moisture hits the underside of the cold (Vermont) roof. Moisture condenses and wood gets soaked. Microbial growth.

Decay fungi, moderate decay of roof sheathing. Sheathing has probably lost 35% strength, maybe more.

ditto