Shingle deterioration on a Calgary Roof Installation

A normal house roof in Calgary will have at least 2 panels (sections), and often many more.  Each of these panels will face towards different points of the compass.  This means that weather will affect each panel differently, and the roofing installation will weather differently on its various parts.  While the variation in weather and sunlight may be slight, patterns become evident over the course of years and decades and wear will become more evident in some areas than in others.
Asphalt Shingles are the most common type of product used in Calgary on a roof installation, and they are affected by weather in 2 major ways: Sunlight and Hail.
Hail damage to a roof installation in Calgary
Hail damages shingles in two primary ways – bludgeoning damage and normal wear and tear.  Insurance companies usually cover shingles that have received bludgeoning damage due to hail, and do not cover normal wear and tear.  In either circumstance, hail impacts cause the gravel attached to the top of the shingle to loosen and/or fall off.  The primary function of gravel  use in shingles is to add weight for increased wind resistance, and to protect the asphalt mat from harmful UV rays.  Once the gravel comes loose on a shingle then it is considered to be nearing the end of its life cycle.  Once gravel loss is at 10-15% the shingle should be replaced.
Sun damage on a roof in Calgary

Sunlight also has two primary effects on the functional lifetime of a shingle – Heat and UV.  Under normal circumstances the effect of heat on a shingle will be negligible.  Proper ventilation should ensure that heat is dissipated instead of building up in the shingle.  If the shingle gets too hot then the asphalt that comprises the mat will begin to deteriorate and gravel will become loose.  We really only see this in instances of obviously bad ventilation.
UV Light is the major cause of shingle deterioration, and Calgary receives more sunlight than any other city in Canada.  Anywhere the UV can penetrate the gravel layer and reach the asphalt mat we will see deterioration of the asphalt itself.  When this happens the gravel becomes loose and more asphalt is exposed to the elements.  In Calgary we see hail falling on our roof installations every few years, and over the course of a decade or more we will see wear and tear becoming evident.

A dual threat to your Calgary roof installation

These forces in tandem can wreak havoc on your roof, and there’s little to be done about it on your current roof.  The only real option is to select the best shingle when it comes time to replace your roof.  This can add 15-30% to the cost of the roof, but will give your home the best chance of staying the course in our increasingly intense Calgary weather.

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