Asphalt Shingle Bonding

An effective and relatively low-cost roofing option, asphalt shingles are one of the most common types of roofing material used on steep slope roofs. When properly installed and maintained, asphalt shingles can last between 20 and 50 years depending on the manufacturer, quality of shingles, and installation method. However, the life span and effectiveness of these shingles can be severely impacted if installed incorrectly, which can lead to possible water damage below.

One of the most important parts of a proper asphalt roof shingle installation is proper adhesive bonding. Adhesive strips are present on all asphalt shingles and help each shingle to stay in place with the shingles around it. If this adhesive strip is not properly bonded or has an inadequate bond, this can increase the likelihood leakage or the shingle blowing off in high winds.

Failure of the adhesive strip can be caused by a number of factors, however the most common reason for this includes:

• Contaminated adhesive strips due to blowing dust or debris
• Shingles installed in cold temperatures or during cold winter months
• Shingles installed in areas that don’t receive full sunlight, such as behind trees or other buildings
• Areas where the granule coatings on the shingles prevent the shingle surface from warming adequately in order for the adhesive strip to bond

These conditions or other scenarios can often prevent shingles from fully bonding and allow the shingles to become inadequately adhered to the shingles below. Since the strip needs a period of time in direct sunlight or become warmed by warm ambient temperatures to bond, shingles in some shaded areas may never fully bond. While a natural proper bond is ideal, shingles can also be hand sealed with roofing cement if they did not originally or will not bond adequately with warm temperatures and direct sunlight. Shingles installed in the winter in colder regions may not properly bond until the spring when temperatures rise and multiple days of direct sunlight warm the adhesive strip.

While there are many other factors that determine the successful installation and extended life of an asphalt roof (such as following manufacturer instructions and regular maintenance), ensuring that the roof shingles are properly bonded is a significant item that can help a roof remain in good condition for years. Having a qualified roof contractor perform regular periodic (twice yearly) maintenance and cleaning of the roof and gutter system is recommended.