You probably already know the basics of ventilation. It’s pretty simple: ventilation is the flow of air through a system of intake and exhaust. So why is ventilation important when it comes to your roof?

Ventilation only works when air flows. There are two ways to create air flow within an attic:

  1. Mechanical. Requires a power source.
  2. Natural. Whenever possible, natural roof ventilation is used.


The stack effect occurs when hot air rises and creates a higher pressure at high points in the attic. Hot air that escapes is known as exhaust. However, this hot air cannot escape without an inlet for cooler, low-pressure air. Cool air that enters is referred to as intake.

When the wind blows against the outside of a roof and increases the volume of intake and exhaust, it is known as the wind effect. Intake and exhaust generate the natural flow of air to create a well-vented attic.

Roof  Ventilation extends the life of your roof.

Have you ever seen icicles build up on the edges of roofs and gutters? This ice buildup is known as an ice dam.  You can see the icicles, but you can’t see the damage that they’re doing to the edge of your roof. Ice damming happens when heat from inside your attic combines with heat from the sun to melt snow and ice on your warm roof. When the resulting water runs to the edge of the roof, it begins to refreeze. As the ice and water build up at the edges of your roof, it can back up behind/underneath the roofing materials, causing damage to your whole roof system, your attic and even inside the walls of your home.

Proper ventilation helps this warm air escape before it has a chance to melt the snow and ice on your roof.  A well-vented roof is easy to see in the winter months. It still has snow on the roof, but not an icicle in sight.

Ventilation benefits a roof when it’s hot outside as well. When the temperature outside rises, the temperature on your roof can be nearly double.  A hot roof over a poorly vented attic translates into a very hot attic.

Why? Unventilated or poorly ventilated attics don’t have an escape route for the heat that builds up. This buildup of heat can damage your shingles from the inside out. An evenly vented roof will allow the hot air to escape keeping your roof and attic cooler.

By far the biggest concern of roof ventilation is removal of vapor. Daily living activities including cooking, showering, talking, and breathing create water vapor. This migrates into the attic space and then must find an exit. If it does not, it will condense in the attic and create mold, mildew, and dry rot. It will also surely shorten the lifespan of the shingles themselves, and in some shingle manufacturer warranty fine print, inadequate roof ventilation will void the manufacturer shingle warranty. A licensed, experienced roofing professional will properly install and properly space your roofing intake and exhaust ventilation.

So in short, yes! You need roof venting on your home. At Renaissance Roofing we will properly vent your roof and address any previous ventilation issues that have happened to your roof in the past.