Roofing Ventilation: How Does It Work?

Roofing ventilation is an important part of sloped roofing systems. Proper ventilation helps protect the roof from damage caused by trapped heat and moisture in the attic. But how exactly does roofing ventilation work?

How Does Roofing Ventilation Work?

Indoor heat and humidity naturally rises and moves towards the highest point of the building, which happens to be the attic. There are two types of attic ventilation systems:

Passive ventilation utilizes the differences in building pressure to create airflow. Vents at the ridges – that is, the highest point of the roof – releases warm and humid air outdoors. This creates negative pressure within the attic that pulls fresh air through vents located at the lowest part of the roof, which is usually the soffits.

Mechanical ventilation utilizes powered exhaust fans to force warm and humid air out of the attic. This type of ventilation may be needed for homes with steep-sloped roofing or high levels of indoor heat and humidity. Mechanical ventilation also can be used to bolster an existing passive ventilation system. 

The Benefits of Proper Roof Ventilation

The following are some of the benefits of having a properly-ventilated roof:

Lower cooling bills – Trapped heat in the attic can radiate back to your indoor living spaces. This can raise your home’s indoor cooling requirements and increase workload on your air conditioning system, both of which can result in higher energy bills. Proper ventilation keeps heat out of the attic.

Ice dam prevention – Ice dams happen during winter when heat from the attic radiates through a poorly insulated roof deck that raises the outer roof temperature to above freezing. The melted ice on the rooftop flows down and refreezes at the roof edge. It eventually forms a dam-like shape that causes problems like icicle formation, water being pushed into the roof edge and water flowing over the gutters and damaging the siding. Ice dams can be prevented with proper attic insulation and ventilation.

Mold prevention – Warm, dark and damp spaces encourage mold growth, which can cause respiratory illnesses and damage to the house structure. A well-ventilated attic is inhospitable to mold spores.

Renovation Team is your leading provider of roofing and siding installation services. Give us a call at (636) 428-3634. You can also fill out our contact form to schedule an appointment. We serve customers in St. Louis, St. Charles and Creve Coeur, MO.