Attic Ventilation Mold

Nope venting an attic is actually pretty hard here s how ventilation is supposed to work.

Attic ventilation mold.

The most common cause of attic mold by far is blocked or insufficient ventilation of the attic space. Attic ventilation is a two part process. This is a 3 12 pitch roof. We have issues with our 1200 square foot home too much moisture accumulating underneath our roof in the attic causing mildew and mold.

Poor attic ventilation not enough ventilation in the attic is the most common reason for black mold being found in attics in places with cold climates. We have 7 roof vents and eve vents every 4. While damp and warm climates are a prime breeding ground for our fuzzy friend other conditions that bring mold include lack of ventilation and proper sheathing. And many homes with terrible attic ventilation are completely mold free.

Additionally poorly designed attic ventilation can be just as problematic. If your attic sheathing doesn t look like new construction and is visibly black or white stained like this picture you likely have a ventilation issue that needs to be addressed and mold remediated. First air enters through the soffit vents. Many of us think the opposite and seal all of the attic vents or even insulate the roof decking assuming it will lower our heating bill.

I know it seems counter intuitive but the basic ventilation principal for your attic is to keep it as cool as possible during the cold season. Insufficient ventilation in that attic. Attics usually have a passive ventilation system in which outside air comes in through the soffit eave vents at the bottom warms up in the attic and escapes through the can or ridge vents at the top because hot air rises. High humidity in a space like an attic can lead to mold and a spill in a carpeted area of your home that isn t quickly taken care of can also lead to mold under the carpet.

This is twice this house had done. For example if a house has poor attic ventilation but the ceiling is well air sealed and the interior of the home has excellent ventilation mold growth will not likely occur. If one of these factors is operating poorly an attic might avoid mold growth by succeeding well in the other factor. Having one but not the other creates poor air flow allowing moisture to accumulate and mold to take hold.

Why does attic mold rarely if ever affect indoor air quality in homes. Ideally your roof will have vents along the ridge as well as along the soffits.