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ROOF VENTILATION FOR SHINGLES

One of the most important components of your roof is the ventilation system. Old homes might not have it or they might have an old system that doesn’t perform well.

You need roof ventilation in your home if there is space between the decking and the ceiling of your dwelling. 

Why is Roof Ventilation Important

  1. Manufacturers of the shingles require it for the whole shingle roof system to work. 
  2. Your Enhanced Warranty requires ventilation to be installed. 
  3. It prolongs the life span of your shingle roof.
  4. The roof ventilation keeps your attic cooler. 
  5. Building Code requires it.

What Is Roof Ventilation

Venting your roof is when you have a way for the colder air to enter the attic space from the eaves and exit the attic space at the peak. 

There are specific measurements for how much air you can have come into your attic and how much you want to exhaust. This is dependent on the size of your roof. 

The International Building Code (IBC) and International Residential Code (IRC) require a minimum ventilation ratio of 1:150 (1 square foot of vent area for each 150 square feet of attic/roof area).

Two methods for NFVA calculation use ratios of 1:150 and 1:300, tailored to ventilation needs per attic square foot. These align with International Building Code standards and Owens Corning's roof ventilation recommendations for optimal air circulation.

What To Avoid When Installing Ventilation

Not every type of ventilation is good for your roof. The best system is eave to ridge venting. Where the air comes in at the eaves and leaves through the ridge. 

The reason this is the best is that it makes sure that there is a transfer of air along every square foot of the attic space. 

Some ventilation systems cause “dead air” in the corners of your attic, meaning that the air won’t vent well enough.

In these portions of the roof, we find that the shingles and even the plywood will degrade significantly faster

For example, gable vents tend to pull air that is directly in line with the vent but neglects the air that sits in the lower corners along the eaves. 

Different Types Of Roof Ventilation Systems

  1. Soffit to ridge vent. If you don’t have a soffit, there are other forms of intake. If you don’t have a convenient ridge, you can add other types of vents at the top. Such as box vents or fans. 
  2. Gable to gable cent. This is an older system and not as effective as, as mentioned above.

Whatever you do, don’t mix systems. If you have gable vents, you need to close them off before installing the soffit to ridge vent system. 

Contact us for a free consultation on your ventilation system. 

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