Roof Vents and Attic Ventilation: Problems and Solutions

General Roofing Systems Canada provides roof ventilation repairs to  throughout Canada.  Roof ventilation Repairs are completed in the following cities; Calgary, Red Deer, Edmonton, Fort McMurray, Lloydminster, Saskatoon, Regina, Medicine Hat, Lethbridge, Canmore, Banff, Cranbrook, Kelowna, Vancouver, Whistler, Winnipeg, Toronto and points between. British Columbia. Alberta. Saskatchewan. Manitoba. Ontario

Roof Ventilation Changed for Proper Attic Air Flow (Condensation Problems)

This is the time of year that we receive a number of calls from homeowners regarding  leaking roof problems.

Some of the top reasons for leaking roof problems are:

  1. Chimney flashing is installed incorrectly and is leaking.
Roof Repair Roof Leak
Replacement of Flashing around the Chimney is done correctly using roof membrane (ice and water) and then proper flashing is installed to back and side of chimney
  1. Skylight flashing has leaks due to incorrect installation.
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Skylight Repair and Replacement in Progress. Premium roof underlay membrane is installed around the skylight which keeps it from leaking.


3. Valleys on roof are leaking. Shingles in roof valleys are commonly done wrong.

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Roof Valley being installed correctly with roof underlay. Roof flashing installed on top, and synthetic roof underlay to rest of roof.
  1. Attic condensation that causes moisture in the attic. The attic moisture manifests as “roof leaks” due to poor roof ventilation. Roof ventilation is not adequate at either the ridge of the roof (exhaust) or at the soffit area (intake).
Roof Sheeting Mold, Attic Mold, Condensation II
Attic Ventilation Problems Cause Condensation and Roof Rot, Mold, Energy Loss, and More

 

  1. Improper Installation of Roof Underlayment.
Re-Roofing, Shake to Asphalt, Coloured Metal Drip Edge - Eave Edge
Properly Installed Roof Underlay : The Ice and Water Shield is installed to roof deck at roof eave edge and synthetic premium underlay installed to rest of roof (complete roof area covered and no wood is left to show, roof tar felt is not used as it dries out and cracks and causes leaks)

 

  1. Improper Installation of Roof Vents and Penetrations
Ice and Water Membrane to Back and Sides of Roof Openings, Wall, Step
Above is an example of proper roof vent installation. This method can be used with any penetration at the roof deck. Roof vent has caulking under vent, high quality ice and water underlay is applied to both sides and to the back of vent which will not allow ice build up to enter under shingles to cause any roof leaks.
  1. Improper Installation of Roof Flashing at Wall (where roof meets a wall).

Shake Roofing, Shake Roof Repair Alberta, General Roofing Systems Canada (Alberta)

OLYMPUS DIGITAL CAMERA
The Roof Flashing at wall base on this home was not done correctly (non existent) on this cedar roof resulting in the home-owner experiencing leaks.

 

The home in the photos of this roof repair were experiencing leaks in there skylights. To resolve this issue, we changed the skylight flashing, which brought forth further attic condensation problems. The combination of the two problems resulted in the roof ventilation needing  to be repaired.

The steps to complete this repair are as follows:

Remove roof vents at peak of roof. 

  1. Remove IKO shingles around roof vents to expose roof underlay.
  2. Remove roof underlayment to roof deck (sheathing).
  3. Remove DuroFlo vent to expose roof attic space.
  4. Inspect exposed roof deck for damage due to attic moisture (condensation).
  5. Install backing to opening and fasten roof deck patch to holes.
  6. Install patch cut to fit each hole.
  7. Install new roof underlay.
  8. Install IKO shingles as needed.

Install 2 new Whirlybird turbine roof vents at peak:
1. Remove IKO shingles at location on roof.
2. Remove roof underlay to expose roof deck.
3. Inspect roof boards for condensation.
4. Cut hole in roof deck to install new vents
5. Attach whirley bird vents to roof deck over vent access.
6. Install new underlayment.
7. Install IKO shingles as needed

Roof Repair, Residence has Attic Condensation Problems

Roof Repair - Attic Ventilation - Whirley Birds

Attic Ventilation, Remove Duroflo Vents to Whirley
Attic Ventilation, Remove DuroFlo Vents and change to Whirlybird turbines
Shingle Roof Repair
New IKO Shingles installed
Roof Repair,
IKO Dual Black Shingles installed Over Vent Hole
Roof Repair - Attic Ventilation - Whirley Birds
Whirlybird Installation for Attic ventilation repair
Attic Vents - Whirley Bird
Attic Vents – Whirlybird
Roof Vents - Remove Duroflo Vents
Nearing job Completion

 

About Roof Ventilation:

Correct attic ventilation provides your roof with the correct amount of airflow to prevent moisture buildup. Moisture in the attic space causes roofing to rot and release condensation. Proper ventilation will help energy costs by regulating the temperature of your home.

Attic ventilation is important to reduce the buildup of heat in your attic which can cause ice dams, shingle decay, condensation, higher energy costs and even mould. Additional ventilation is often required in older homes to meet the BC, Alberta, and Saskatchewan Building regulations. This is also required to meet  the shingle manufacturer warranty requirements.

Attic ventilation can be corrected:

The roof repair above shows us adding roof vent turbines (whirley birds) to increase air flow to the attic in this home. You can also install ridge vents or more conventional roof vents.

How to Calculate Proper Attic Ventilation:

There is no such thing as having too much attic ventilation.  Realistically you want your attic to be the same temperature as it is outside in the winter and in the summer you want  to be able to get the warm air out.

The primary focus when  ventilating an attic is to not actually bring down the attic temperature (of course this would be beneficial in summer when your house and attic are hot). The main reason for ventilating the attic is to eliminate the moisture in your attic space that causes roof leaks and a host of other problems such as; ice dams, rot, shingle warranty problems, paint peeling and mould. Improper venting causes your house to sweat and not breath right.

The following is how you would calculate the proper amount of ventilation required for an attic:

  1. Multiply the total square footage of your attic space by 144.
  2. Divide the total above by 2.
  3. Divide total above by by 300.
  4. What is called the “net free” area you now know. The net free square inch area required for intake ventilation (for example at soffit) and the exhaust ventilation (for example the vents at the ridge as in the photos above).
  5. Divide the “net free” area by the ‘”net free'” area the Ventilation Product Manufacturer provides on the box. This will be your calculation for how many roof vents you need to install for correct attic ventilation.

Attic Solution – Keep the Heat Under Control With Proper Attic Ventilation!!!

Until Next Time,

The Team at GRS

CONTACT US:
General Roofing Systems Canada (GRS)
24 Hour Emergency Roof Repair: Call +1.877.497.3528 toll-free.

info@grscanadainc.com

Calgary, Red Deer, Edmonton, Fort McMurray, Lloydminster, Saskatoon, Regina, Medicine Hat, Lethbridge, Canmore, Banff, Cranbrook, Kelowna, Vancouver, Whistler, Winnipeg, Toronto and points between. British Columbia. Alberta. Saskatchewan. Manitoba. Ontario

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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CONTACT US:
General Roofing Systems Canada (GRS)

24 Hour Emergency Roof Repair: Call +1.877.497.3528 toll-free.

info@grscanadainc.com.

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