Choosing the Right Roof Ventilation

General Roofing Systems Canada installs roof vents throughout Canada. Roof vent service in Toronto, Calgary, Red Deer, Edmonton, Fort McMurray, Lloydminster, Saskatoon, Regina, Medicine Hat, Lethbridge, Canmore, Banff, Cranbrook, Kelowna, Vancouver, Whistler and points between.

Roof ventilation is one of the most misunderstood components of the roofing industry. Unfortunately, we respond to roof leaks all the time that are a result of improper ventilation, and the company that installed the new roof system did not even consider it. Worse yet, many companies install brand new roofing products which will only last a portion of the time it should after their clients pay good money. This is obviously a sore spot for the roofers here at GRS.

“Improper roof ventilation will cause your roof to not perform correctly and will cause ice damming, sheathing rot, mold, condensation, leaks, and will cause your roof membrane or roof shingles to deteriorate prematurely.”

The ratio of roof vent exhausts on a sloped roof is about 250:1. In other words, you need about 1 sq. ft. of roof vent (or exhaust from your roof) for every 250 sq. ft. of roof deck. This should be equal to the roof system intake, which is typically located under your roof soffits.

The main types of vents for your roof and attic are as follows:

  • Standard Roof Vents or Roof Louvers: These are the standard vents that are
    Lomanco Standard Roof Vent
    Lomanco Standard Roof Vent

    typically the ones you see everyday on sloped roofs (if you have ever stopped to notice, we know roof venting is a boring topic). These roof vents are available in a variety of styles and colours.


  • Whirlybirds or Turbine Roof Vents: Whirlybird vents, turbo vents, or roof
    Turbine Vent - Duraflo
    Turbine Vent – Duraflo

    turbines, as they are called generically, are the ones you see on sloped roofs that turn in the wind.

  • Powered Roof Vents or Solar-powered Roof Vents: Powered roof vents need to be hooked up by an electrician (as they use power), and solar-powered ones are obviously powered by the sun. A caution to solar buyers – be sure to use a reputable solar vent supplier and an installer of the roof vent that know what they are doing.

One of the suppliers we recommend is Lomanco. The Omni Solar Roof Vent by them is of excellent quality and the vent itself performs as advertised and performs very well. Information on this solar roof vent IIvent system is available here.

  • Ridge Line Vents or Roof Ridge Vents: Ridge venting is one method of roof venting we recommend to our customers often. The ridge vent allows constant, even predictable roof or attic ventilation. In areas in the north such as Edmonton, Fort McMurray, Lloydminster, and Saskatoon, the ridge vent can save your home from leaking due to attic condensation when snow loads will cover over the exhaust of traditional ventilation systems.
Ridge Vent on Shingle Roof
Ridge Vent on Shingle Roof

Ridge venting is more costly as the sheathing at the ridge of your roof needs to be cut on both sides for the system to be installed. However, it is well worth the cost. Lomanco, Duraflo, and GAF are our suggested providers for this system.

  • Gable Vents or Attic End Vents: Self-explanatory. This system is found on the end of your home at the gable siding.
  • Intake Vents or Soffit Vents: The intake portion of your attic venting is typically in through the soffits. There are a number of soffit style vents. Stay tuned for our blog article on calculating intake venting.

Until next time,

The Team at GRS

Miscellaneous General Roofing Documentation

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