Ventilation

The Ins and Outs of Roof Exhaust Vents

Winter rains have arrived and the summer’s warm, dry air has been soundly replaced by cold moisture. This can prevent a problem in your home if your roof isn’t properly ventilated. When you turn on the heat in your house in the winter that now warmed, moist air accumulates at the highest point in your home, and without an escape route through a roof exhaust vent or attic exhaust fan, that trapped air encourages mold and mildew growth and creates a stale odor. 

To avoid these problems, it pays to ensure your roof exhaust vent is properly installed and maintained. 

Types of Roof Exhaust Vents

There are different types of roof exhaust vents:

  • A box vent is a hole that is cut through the roof that has a box cover over the opening. Box vents are positioned near the roof peak for maximum exhaust ventilation. 
  • The ridge vent is a continuous strip of plastic material covering a strip of removed roof deck about one inch on both sides that allows continuous airflow due to convection. There must be an equal intake to output ratio in order for air to convect upwards and out of the building. 
  • A stem vent is used to connect your bathroom, kitchen, or dryer fans to allow the moisture to escape properly and reduce moisture in the attic and in your home

All of these roof exhaust vents are non-powered or passive, working in tandem with soffit vents that sit at the lowest point of the roof to draw in outside air. The two types of vents together circulate the air keeping the heat and moisture to a minimum and your attic properly ventilated.

Power Fan Exhaust

In addition to roof exhaust vents, there are also attic exhaust fans. They work under the principle that hot air rises, but here instead of the hot air simply escaping through vents, it triggers an electric-powered fan to switch on to push the hot air outside. This creates a powerful suction drawing up the warm air and blowing it out through the roof. Removing heat in the attic stops the heat from radiating down into the house which then keeps the air conditioning unit from turning on, making it more efficient. While a very efficient solution for keeping a house comfortable, the fans are installed below the roof and can be quite heavy, so they cannot be installed on every type of roof. 

Attic roof vents are similar to bathroom and kitchen roof vents in that they all suck “bad” air up and out of the house. However, bathroom and kitchen exhaust vents are smaller and powered by exhaust fans that you turn on when needed. Kitchen and bathroom vents can also be directed to release air through the home’s siding, not just the roof. Those metal protrusions you see on the sides or tops of houses are usually exhaust vents that have a type of protective covering to keep moisture and pests from getting inside.

Inspecting Roof Exhaust Vents

Having roof vents is a critical part of keeping your roof in good shape and your home comfortable, but having them is just part of the solution. Regular inspections and maintenance of roof exhaust vents, and ensuring they were installed correctly, are also part of the effort. 

Contrary to popular belief, warm weather doesn’t produce moisture on nail heads, but cool weather outside and warm attics will. This is because the cold transfers through the steel nail, putting a cold rod into a warmer attic, creating a dew point where the warmer air carrying moisture meets the cold steel and condensation begins. This is the same as when you put a glass of ice water on the counter and it collects dew on the outside of the glass. The moisture in the room gravitates to the colder surface. This is exactly the same process on the nail in the attic.

The best way to ensure proper roof exhaust venting is to hire a professional roof contractor to conduct an inspection. Pacific West Roofing offers roof exhaust vent service starting with having our expert inspectors assess your roof, attic, and vents for signs of damage or blockage. Then repairs and replacements can be made to ensure your roof is sound and sufficiently ventilated. Hiring the best and most experienced  professionals to install your roof exhaust vents in the first place can go a long way in keeping your roof, your home, and the very air you breathe inside your home in tip-top shape. Contact Pacific West Roofing to find out how we can serve your roofing needs. 

Portland Roofing Contractor Since 1980

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