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877.784.ROOF (7663)
Effects on Roof's 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.
Snow and ice: Melting snow often refreezes at a roof’s 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 buildup of relatively warm, moisture-laden air. Moisture in a poorly ventilated attic promotes 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, causing rot. 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 rot and deterioration. Trees and bushes should be trimmed away from homes and buildings to eliminate damp, shaded areas, and gutters should be kept clean to ensure good drainage.

Trees 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, or even puncture, shingles and other roofing materials. Leaves on a roof system's surface retain moisture and cause rot, and leaves in the gutters block drainage.
Missing or torn shingles: The key to a roof system's effectiveness is complete protection. When shingles are missing or torn off, a roof structure and home or building interior are vulnerable to water damage and rot. The problem is likely to spread - nearby shingles also are ripped easily or blown away. Missing or torn shingles should be replaced as soon as possible.
Shingle deterioration: When shingles are old and worn out, they curl, split and lose their waterproofing effectiveness. Weakened shingles easily 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-it should be replaced as soon as possible.
Flashing deterioration: Many apparent roof leaks really are 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.
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Roofing
Division Technical
Services Bulletin Bulletin
Number: RD – |
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SUBJECT:
The Effects of Hail Damage on
Asphalt
Shingles
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DATE: May
9, 2006 FROM: Mel
Sancrant - BMTS, Toledo PHONE:
(419)
248-5500
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MESSAGE:
When
an Owens Corning 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, and
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 indentations 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 Owens Corning Limited Warranty on Roofing Shingles is void when
shingles are damaged due to the evidence of hailstorms under all conditions
stated above.
877.784.ROOF (7663)
