Why And How To Improve Attic Ventilation

Proper attic ventilation is critical to the health of your roof with 2 major roles – reduce heat build up and control moisture.

Heat control

Heat has a significant impact on asphalt roof shingles and flat, asphalt based roofing. While they are designed to be weather resistant, they will become soft and pliable when exposed to enough heat. It makes them easy to tear and shed their UV protective granules. As these asphalt based materials heat up, then cool and contract over time, they become brittle and subject to cracking or breaking off.

While we do not have the extreme sun beating down on our roofs, heat damage from trapped air in attic spaces has the same impact. 

In winter, excessive trapped heat can lead to ice dams. 

Moisture control

“Attic moisture problems can lead to mold, mildew, or other biological growth. The absence of proper attic ventilation fosters attic mold growth by allowing moisture to become trapped in the attic. Moldy attic conditions could lead to rot, structural damage [rafters and roof decking], and a variety of health problems for susceptible individuals.” — Advantaclean

Adequate ventilation will help control both heat and moisture within the attic or upper crawl space. As a bonus, it will improve overall energy efficiency.

Is your current ventilation adequate?

For many, there are already identified problems indicating a ventilation issue, either visible damage or during a routine inspection or cleaning. If you haven’t noticed issues, we recommend determining if your current ventilation is adequate as a preventive measure. 

How much is needed?

“The U.S. Federal Housing authority recommends a minimum of at least 1 square foot of attic ventilation (evenly split between intake and exhaust) for every 300 square feet of attic floor space. Always have a balanced ventilation system.” — GAF

The linked page includes a handy calculator to determine if your ventilation needs are met. Keep in mind that too little insulation and other factors could impact your specific need. Too much ventilation is also a problem, so checking with a professional is always advised.

Typical forms of roof and attic ventilation

Soffit vents are “installed into the underside of your home’s eaves that permits fresh outside air to be drawn up into the attic. (– Home Advisor).”

These are intake vents designed to draw in cooler air. Since heat (hot air in this case) is pushed up as cooler air settles, soffit vents can leave trapped air without adequate exhaust vents.

Ridge vents along the peak of a roofline solve that issue. These continuous vents can be installed on an existing roof and provide a way for heated air to escape. 

Additional exhaust vent options include:

• Static vents in peaks using wind to draw heat out.
• Powered vents in peaks for better efficiency.
• Turbines which spin to draw heated air out.
• Hip ridge vents which are similar to ridge vents and used primarily when there is less horizontal roof ridge surface. 

Adding more ventilation.

In most cases, it isn’t difficult for the DIYer to install vents, but a small mistake could have significant consequences leading to increased costs later. 

Like with skylights, exhaust options require being on a roof (with its associated risks) and cutting holes in the roof. 

The later, when not done with care, can lead to damaged shingles, wiring and insulation, and over-sized openings. 

Improper installation of flashing, sealing, and re-installation of shingles. Each of these has the potential to provide an access point for water. Even the smallest gap is enough to create problems later – and they may not show up for some time.

Care and maintenance

Increasing the number of vents means more potential failure points. If you don’t have routine inspections now, we’d highly suggest setting up a maintenance schedule. 

Sealants and rubber boots breakdown over time. Debris can get caught under and around flashing and shingles. 

Is your roof properly ventilated?

If you are unsure, or haven’t had a routine inspection in the past year, now is the time to check. If we identify a need, we can add the necessary ventilation.