Attic Mold?

[Bossard Steven]

I was recently in an attic and there was ridge vent and no eave vents so the ventilation was marginal. The problem was the is a green dust on the ceiling and rafters. What is this, mold? What would you tell a home owner to do about it?

[Scott Patterson]

I was recently in an attic and there was ridge vent and no eave vents so the ventilation was marginal. The problem was the is a green dust on the ceiling and rafters. What is this, mold? What would you tell a home owner to do about it?

Again, photos would help.

[Eric Barker]

What is this, mold? What would you tell a home owner to do about it?

Mold comes in thousands of species and many colors. Only a lab analysis would confirm that it is mold. It may sound hokey but saying that there is a "mold like substance" is your best course even it you "know" it to be mold.

[Bill Hetner]

well your description says green dust not mould. there is a difference. is there any possible reason why there could be green dust? or mould? ask questions and if the home owners are worried about it have it sent to a lab to be checked out. might be nuthing or something serious. hard to call from here.

[Curt Downs]

I'm not sure what the 'green dust' is, but a ridge vent without a properly sized soffit vent is a definite problem. That would void roofing shingle warranties (leading to early failure of asphalt/fiberglass shingles due to overheating of the attic/roof areas), and in a cold climate lead to ice dam formation in the cold and snowy months (resulting in water intrusion and possible very big repairs). The lack of soffit (eave) vents needs to be corrected.
Curt Downs
HIC# 0622501
CT

[Robert Ernst]

If it were me I would comment on the green dust and recommend it be tested if there is a concern. I wouldn't even call it Mold. If it looks like its growing on the wood state it's unknown organic growth. As for the vents it's very important to get some lower vents in. The vents down low need to be the same amount of area at a minimum. It's better to have slightly more vents below than above. The heat it going to rise out of the upper vent no matter what and is currently pulling the air from inside the home. If you put more vent lower than higher you will ensure that there is always enough air coming in from the outside of the home.

[Rick Bunzel]

Green dust is a new one. Attic mold is very common here in the Pacific NW. I see it in 5% of the homes I inspect. At the most recent WW-ASHI conference we had two different speakers talk about it.

Mold comes in all colors. If your seeing spots on the underside of the roof deck, its most likely mold spores. Another telltale is that the spots are on the north/east sides of the attic and not the south/ west sides. Warm most air is coming in from the living spaces and condensing on the cool side of the roof deck. Some times its a ventilation issue, other times its an air leak issue and sometimes its a combination of issues.

Here is what I saw at today's inspection.

[John Dirks Jr]

This might be more progressed but does it look anything like this?