Attic Mold, Why is it Growing Under the Roof? And a Mold Solution


Let’s dig into the attic mold and find out why is it growing in your attic.

There are actually several different reasons that might be responsible for the mold to appear under the house roof… and sometimes compromise your perfectly going real estate transaction. The “house selling” is just one of the reasons, why attic evaluation and attic mold treatment (if you’re out of luck) should be performed before even putting your house on the market.

Unfortunately, the attic is one of those completely off limits house areas for many homeowners. Whatever happens there, often stays there, without anyone ever noticing it. Therefore, I decided to bring a little House Attic Mold awareness into your daily routines, and hope you’ll find it helpful.

Why is mold growing under your roof?

10 major factors that might cause attic mold to grow on your roof decking

  1. #1 cause of attic mold growth in cold climates is an inadequate attic ventilation
  2. Improperly designed attic ventilation – combination of vents that instead of exchanging the air between exterior and interior, they trap, create pockets of “dead air” which condensates on roof decking during the cold season
  3. Dryer / kitchen / bathroom vent discharging into the attic often causes condensation, frost and mold growth on decking surface
  4. Inadequate / missing attic floor insulation – allows for heat transfer from your house into the attic area
  5. Improperly insulated cathedral ceilings and skylight chases are often contaminated with mold
  6. Furnaces and water heaters produce heat and if installed in a poorly ventilated attic (not contained within a dedicated / enclosed area), could be responsible for condensation and mold
  7. Plumbing vents open into the attic discharge moisture saturated sewer gases
  8. Uninsulated forced air heating system ducts – in cold climates they waste precious energy and increase chances for mold in your attic
  9. Poorly insulated ceiling penetrations, attic access panels, kitchen soffits open into the attic, etc.
  10. Leaking roof – mold in the attic caused by the failing house roof protecting surface will be usually concentrated in leakage area and below it. However, poor attic ventilation could significantly accelerate mold growth.

Combining just first two items responsible for attic mold could transform your attic into the steamy, mold-contaminated room during the cold season. Any warm air trapped under the roof will cause condensation to form on framing, decking surfaces, and roofing nails creating mold nesting habitat.

Some homes have more than one attic and upper one, usually located above the bedrooms and bathrooms is always more susceptible of being contaminated with mold. Warm air from lower parts of the house will naturally rise up, transfer through the ceiling and all its penetrations into the attic.

Attic mold solution: it has two parts and both must be executed at the same time:

  1. Attic mold removal – procedure often depends on the extent of the contamination
  2. Correction of factors responsible for attic mold – without it, attic mold will most likely re-appear within one season

Once everything is properly corrected, you won’t have to worry about any attic mold growth. However, I still highly recommend to periodically monitor the attic. Since you already know, why is the mold growing in the attic it is time to do some investigation above the ceiling.

Be extremely careful, if you don’t feel comfortable with accessing the attic, find somebody else to do it for you!

Pick a cool day for this trip, powerful flashlight and a dust mask. Attic access might be as easy as pulling down folding attic stairs, but sometimes it is a challenge as far as size of an opening and its location.

Shine your light beam above your head and onto the roof decking / framing surface, check carefully areas where attic floor meets the roof, because that’s where attic mold usually starts appearing.

If you see no discoloration, clean wood surface with no residue on it, than everything might be OK and you are one of those who don’t have to worry about attic mold.


Source by Dariusz Rudnicki