There seems to be a greater

concern these days about mold

found in homes and the

unhealthy affect it can have on

the home and it’s residents.

While we do find a fair amount

of mold in basements, mostly

damp corners from water

seepage through basement

walls, or from single event or

regularly occurring flooding,

most people are surprised

when we climb down out of the

attic and announce that we’ve

discovered mold.


    Mold in the attic? You would think, since it is so hot and dry up there in the summer, that mold wouldn’t be a problem. But believe it or not, attics are where we see the worst mold problems.


    Attic mold is usually found on the underside of the roof, the sheathing that the shingles are nailed to. In older homes, the sheathing is made up of boards. In newer construction it is usually plywood or oriented strand board (OSB). What happens is that indoor moisture rises up through the house and into the attic space. In the winter, when this warm, moist air hits the back side of the cold sheathing, it condenses. If the conditions are right, the sheathing stays wet and mold appears.

    Excessive indoor moisture levels, lack of proper attic ventilation. and lack of adequate insulation can all contribute to a moldy attic. Excessive moisture in the house is often associated with damp conditions in the basement or crawl space, and more often than not, this is the main culprit.

    Proper ventilation in the attic will dry any moisture getting into that space. Adequate insulation will prevent moisture from getting into the attic in the first place. Dry conditions in the basement or crawl space will keep the indoor moisture levels reasonable. New construction addresses all of these conditions, but older homes may suffer from one or more of them.

    The mold can be small brown, gray or black spots, here and there, often mostly on the north facing roof that never gets much sunlight, and may feel dry to the touch. Sometimes it will be limited to the area near where a bathroom fan vents improperly into the attic, instead of to the exterior. Or it can be everywhere - black and wet - and at this point it can actually begin breaking down and weakening the sheathing.

    Often, the mold we find is old and inactive, the problems that caused it having been corrected - more insulation, more ventilation, the water problem in the basement resolved. At this point, the problem is merely cosmetic, but still something you may have to explain to the next buyer when you sell the home.

    Testing by a certified mold technician is the only way to tell for sure how bad, or toxic, the problem is. They’ll take swab samples and test the indoor air quality for spores. There are many ways to get rid of the mold, but the conditions that caused it in the first place must also be addressed - or it will simply return.

    The mold can be removed by the homeowner or a mold remediation contractor in a variety of ways, using fungicides and/or disinfectant solutions. Bleach is generally not recommended. The area can also be painted afterwards with a mold resistant stain blocker. The work can be difficult to do in a cramped, dark  attic, with insulation underfoot and roofing nails protruding from the sheathing. We’ve heard of a method of blasting away the mold with dry ice, but haven’t seen it demonstrated.

    So, if you have mold in your attic, it may be a small problem, a large problem, or no problem at all. Check with a reputable, qualified contractor to be sure, and look online where you’ll find a great amount of information on the subject.


Campbell and Davies LLC    201 Dey St Suite 211 Ithaca, NY 14850   

607 216 0036    fax 607 216 0402   campbellanddavies@yahoo.com   


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