Important Facts About Roof Ventilation

January 19, 2024

As you might have read on our previous blog, your roof is a complex system of layers that work together to protect your home. Over the years, roofing knowledge has progressed to where it is today. With a greater understanding of what works and what doesn’t, today’s roof systems are able to withstand many years of weathering before needing to be replaced. One of the layers on a roof system that in prior years was neglected was the roof ventilation. In fact, according to, the need for roof ventilation was not documented until the early to mid-20th century. 

A properly ventilated roof system has adequate intake and exhaust ventilation, and a specific calculation is required to ensure that cool air is pulled into the intake and the hot air in the attic is being pushed through the exhaust. 

An inappropriate amount of intake or outtake ventilation can “short circuit” the ventilation process, preventing the system from pulling in cool and pushing out the hot air. 

Roof ventilation is important because the house and roof need to “breathe”. Having proper ventilation prevents moisture build up which can cause mold and mildew in the attic. An improperly ventilated roof system can cause premature failure of the roof materials. Having proper roof ventilation can extend the life of your roof. Ventilation is so important in fact, that most manufacturers will not warranty products installed without proper ventilation. 

Having proper ventilation on the roof system can prevent ice damming. If you’ve ever had icicles on your eaves, then you’ve been the victim of ice damming. Ice damming occurs when the heat from the attic causes the snow on the roof to melt. The melting snow slides down the edge of the roof and then refreezes. The ice and water that builds up at the edge of the roof can back up under the roof materials and cause damage. Ventilation stops this from happening because the warm air is pushed through the exhaust vents before it heats up the attic enough to melt the snow. 

Ventilation is also an important component in keeping the house cool and reducing energy costs. When hot air is allowed to escape from a properly ventilated roof – it reduces the amount of work on your air conditioner, which in turn reduces energy cost. 

If you feel like your roof needs proper ventilation, call a professional roofing contractor like American Eagle Roofing to help.