Mold Advice

I did a roof inspection last night and ran across one rafter that had several dark “patches”. I’ll be the first to admit, although I could design the roof structure, I am very weak in recognizing mold, which is why I do not offer mold inspections. The rafter in question tested at only a 5% moisture content which makes me think it is not mold. Also it was the only rafter in the attic that had these black patches. What are your thoughts?

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Look for a vent stack or Bath/kitchen vent under the lowest part of the roof and the moisture can gather in that section only .
This could have happened when the weather is cold .
The vent exhaust could even be under the insulation .
This drove me nuts the first time I saw it until I found the plumbing vent just under the insulation
Roy Cooke sr…RHI…

I only took the pictures of one small area, but the patches ran the entire length of the rafter. Do you think it may be mold?

yes the rafter acts like a race way with the warm moist air following it all the way up and condenses on the cold roof. I would report it a dark stain possible mould . .I would also tell the people that ( If it is a vent ) that extend to the outside and not be concerned as it needs moisture to grow and this being ( Normally ) a very dry area it should not happen again .
Roy Cooke sr. RHI…

Canadians use English spelling for many things including ( Mould )