How Attic Ventilation Can Help Protect Your Home From Mold

Attic ventilation is a key component in most good residential roofing systems. Unless your roof is designed to function without ventilation (called a "hot roof"), poor ventilation can almost literally be the death of it. But it's not just your roof that you need to worry about.

If your attic is unventilated and collects hot moist air throughout the day, your entire home can be affected. Attics are a common place for mold problems to start, and since you may not notice the problem as quickly as if it had started in your living space, the mold infestation can become strong and start to infiltrate your walls, basement, and living space before it's caught.

Here's how having a roofing contractor improve your attic ventilation helps protect your home from the threat of mold.

Vents moist and warm air rising from the living space and basement

Moist air makes for a damp, humid environment, which is ideal for fast mold growth. Mold can sometimes grow in areas with moderate humidity, but regular high humidity levels make it much more likely. 

A properly designed attic ventilation system reduces the amount of warm, moist air in the attic considerably. A typical system consists of vents at the soffit (under the eaves) to allow air in and vents at the ridge to allow air out. As warmer air travels upwards, it exits the vents, creating a suction that pulls fresh air in through the lower vents.

Helps prevent condensation from forming

Although it loves moist air, mold also loves damp or wet materials. Mold spores float through the air in your home on a regular basis, but a hospitably damp surface is what the spores need to sprout and thrive.

That's why mold is so likely to show up in poorly insulated and poorly ventilated attics. The moisture in the air tends to condense on the under-surface of the roof during cooler seasons or at night, when the roof deck surface is cooler than the attic air. The more condensation there is, the wetter (and more mold-friendly) the roof deck's surface becomes. Eventually, condensation can also start to drip down onto the attic floor and the floor insulation, making those surfaces increasingly mold-friendly as well.

A good ventilation system is constantly venting the warmest (and therefore wettest) air from the attic, so the air that stays in the attic will tend to be less saturated and won't condense as easily. In addition, condensation works best in stagnant air, and a good ventilation system keeps the air moving so the air does not grow stagnant.

As you can see, attic ventilation systems can be an efficient, well-thought-out way to reduce the humidity and stagnation in the air and to reduce mold-friendly dampness and condensation.