With 30, 40, and even 50 year asphalt shingle roofs on the market today, it can be confusing why reserve studies rarely reflect the manufactures life expectancy?

So why all the confusion?

Actual Life vs. Manufacturers Warrantee

Will a 50 year warrantee mean that the roof will last 50 years? Possibly, if perfectly installed, and perfect conditions exist for the roof over the life of the shingle; but most likely, no. So what causes a roof to fall short of this life expectancy?  

The four areas that we are usually concerned with during a reserve study are material and composition, ventilation, previous installation, and physical damage.

Material & Composition

Shingles are sold with manufacturers warrantees’ from 20 – 50 year, generally depending on the shingle type and thickness. Architectural laminated shingles will generally last longer than 3-tab shingles and carry higher wind resistance due to its increase weight. As the roof ages, deterioration to the shingle will occur most notably on southern exposures where buildings are most impacted by heat and weather. In hotter climates the suns heat can be a significant factor in early deterioration of asphalt shingles.

Roof Ventilation

Improper roof ventilation or lack thereof will greatly contribute to the early failure of a roofing system, by promoting higher surface temperatures to the shingle surface.

Layered Roofing

It is not uncommon to find layered roofing, where a new roof has been installed over the old shingles, without a full tear-off. This type of installation is less expensive than a full tear-off but will reduce the life expectancy of the new roof.

Physical Damage

Shingles are wind rated so you should have a roofing system rated for your area, however improper installation or winds in excess of the roof rating can cause tears and blow-offs of roof shingles. Most asphalt shingle roofs on the market today, approximately 90%, are made of a fiberglass material. Fiberglass shingles are lighter and more durable than their organic predecessor but are more prone to tearing and wind. Other common areas of leaking can occur at roof penetrations or from nearby trees.

In California we typically rate 20 year roofs at 20 years, 30 year roofs at 25 years, and 40-50 year roofs at 30 years. Of course we all hope for the optimal life expectancy but conservative planning for the average is always recommended.

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