What is an Asphalt Roofing System?

When you replace your roof, you are purchasing a full roofing system.  Your current roof will be stripped down to the wood decking and the decking will be inspected for any water damage.  On top of the wood decking we install a layer of waterproof underlayment sometimes known as “roofing felt”.  This layer is the most important part of your roof as it is the vapor barrier protecting the wood decking underneath.  On top of this underlayment we start to build the components of the roof including Ice & Water Shield if you live in a zone that requires it.  Protection like flashing is installed in the valleys (dips) and vertical corners of the roof protecting any transitions to a wall or chimney.  Drip edge is installed along the gutter line which helps ensure that water will run off into your gutters and not behind them!  A roofing starter strip is attached along the roof edges (also called Eaves and Rakes) which help your first layer of shingles grip to the roof edges.  Finally the asphalt shingles are nailed on top of the roofing starter strip and are placed from the edges of the roof up to the peak line, creating an overlapping pattern.  The overlapping pattern is especially important for dips in the roof (called valleys).  This complete roofing system is a requirement for all asphalt roofs to ensure weather protection throughout the different layers of the roof.

The asphalt shingles that you choose are the visible part of the roof surface that can be a beautiful, aesthetically  pleasing part of your home.  Different color selection and high-definition styles can bring out different shadows and depth to the roof making the colors pop in different ways.  High profile ridges are designed to create high definition shadows giving a high-end classy look to the entire home.   

What is blistering on an asphalt shingle?

Ventilation is a key component to your roof. Proper ventilation of your attic space not only reduces the cost of your energy bills but also protects the roof from damage (due to overheating). High temperatures in the roof can cause a blistering consequence in the shingle, creating granule loss.  To understand why a shingle blisters, we must know the components of an asphalt shingle:

Asphalt shingles are manufactured from different layers of organic and synthetic materials, starting with an organic or fiberglass mat. This mat is covered with liquid asphalt, (hence the name asphalt shingles).  This liquid asphalt is then covered in crushed limestone to create fire resistance, and then finally coated in granules of different colors of choice to protect it from the sun and giving the shingle its appealing colorful look. Adhesive backing is added to help the shingles bind together once they are applied to a roof.  Because of the nature of the shingle’s make-up, extreme high temperatures can cause tiny air bubbles trapped in the surface of the asphalt layer to “pop”, compromising the bond between the granule and the asphalt layer.  The granule loosens and runs off the roof with rain and wind making the shingle appear to have tiny holes where the missing granules were.  This “blistering” is common at the peaks of the roof or in areas at the highest temperatures.  This is rarely a concern in small quantities as other layers of the roof still offer water protection, but in large quantities can compromise the shingle’s integrity.   

A roof inspection can reveal if your roof is having a blistering problem.  Your roofing estimator might offer more ventilation as a solution to stop the blistering problem for your new roof. 

Here is how more ventilation helps to stop blistering: Hot air rises up.  Therefore the area of highest temperatures is at the peak of your attic and usually shows the most amount of blistering on the roof above … so …. A great solution to a blistering roof is a ridge vent.  The ridge vent is attached to the peak of the roof (also called the ridge) and since hot air always rises, the hot air escapes at the very peak.  Soffit vents would be the next logical suggestion to create an intake of cool air and allow for circulation for the air to escape through the roof.

Our roof evaluators are thorough in their inspections and have a trained eye to spot roof blistering.  They will mention if they found signs of blistering (with photo evidence of course) and may offer different kinds of ventilation as a solution.  If your roof inspection reveals blistering on your asphalt shingles, consider adding roof ventilation, which comes with the additional perk of saving you money in air conditioning costs.