Effect on Roof Performance

Sun: Heat and ultraviolet rays cause roofing materials to deteriorate over time. Deterioration can occur faster on the sides facing west or south.

Rain: When water gets underneath shingles, shakes or other roofing materials, it can work its way to the roof deck and cause the roof structure to rot. Extra moisture encourages mildew and rot elsewhere in a house, including walls, ceilings, insulation and electrical systems.

Wind: High winds can lift shingles’ edges (or other roofing materials) and force water and debris underneath them. Extremely high winds can cause extensive damage. These should be replaced as soon as possible.

Snow and Ice: Melting snow often refreezes at a roofs overhang where the surface is cooler, forming an ice dam. This blocks proper drainage into the gutter. Water backs up under the shingles (or other roofing materials) and seeps into the interior. During the early melt stages, gutters and downspouts can be the first to fill with ice and be damaged beyond repair or even torn off a house or building.

Condensation: Condensation can result from the build up of relatively warm, moisture-laden air. Moisture in a poorly ventilated attic promotes the decay of wood sheathing and rafters, possibly destroying a roof structure. Sufficient attic ventilation can be achieved by installing larger or additional vents and will help alleviate problems because the attic air temperature will be closer to the outside air temperature.

Moss and Algae: Moss can grow on moist wood shingles and shakes. Once it grows, moss holds even more moisture to a roof system’s surface, which leads to continued rotting. In addition, moss roots also can work their way into a wood deck and structure. Algae also grow in damp, shaded areas on wood or asphalt shingle roof systems. Besides creating a black-green stain, algae can retain moisture, causing deterioration. Trees and bushes should be trimmed away from homes, condos and buildings to eliminate damp, shaded areas. Gutters should be kept clean to ensure good drainage.

Tree and Leaves: Tree branches touching a roof will scratch and gouge roofing materials when the branches are blown by the wind. Falling branches from overhanging trees can damage and even puncture shingles and other roofing materials. Leaves on a roof retain moisture and cause rot, while leaves in the gutters block drainage.

Missing or Torn Shingles: When shingles are old and worn out, they curl, split and lose their waterproofing effectiveness. Weakened shingles are blown off, torn or lifted by wind gusts. The end result is structural rot and interior damage. A deteriorated roof system only gets worse with time and should be replace as soon as possible.

Flashing Deterioration: Many supposed roof leaks are actually flashing leaks. Without good, tight flashings around chimneys, vents, skylights and wall / roof junctions, water can enter a home or building and cause damage to walls, ceilings, insulation and electrical systems. Flashings should be checked as part of a biannual roof inspection and gutter cleaning.

Effects of Hail Damage on Asphalt Shingles: When a roof has been exposed to a hailstorm severe enough to cause granules to be dislodged from the surface of the shingles (in spots large enough which expose the asphalt), the roof has been compromised. The colored granules, which are placed on the surface of the shingle, serve two purposes:

1. They provide an aesthetically pleasing product.
2. They protect the underlying asphalt from exposure to the sun.

Prolonged exposure to sun causes asphalt to deteriorate. This is the reason that a hail damaged roof will tend to fail prematurely.

Heavy hail damage is obvious because of the indentation in the shingle. When the surface damage of the shingle is not visible, look for indentations on vents, ridge vents, siding, or any other softer metal objects that may show impact. The effects on the shingle may not be apparent for about a year. At this time, circular areas of granules will fall off the shingle. This is often called spalling. What has occurred is that the impact of the hailstone has broken or weakened the bond between the granules and the asphalt. After a year or so of weathering, the granules fall off the shingle in the circular area of impact. With granules missing, the sunlight (UV) quickly attacks the asphalt and the maximum performance of the shingle has been compromised. The limited warranty of roofing shingles is void when shingles are damaged due to the evidence of hailstorms under all conditions stated above. Consider starting a bi-annual inspection to determine if you've had any damage.