Roofing Basics
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Algae Growth
Algae growth causes a dark discoloration on roofs. The algae is usually brown to black in color which results in a streaked, dirty looking rooftop. It can be mistaken for soot, dirt or tree droppings, which typically produce only localized discoloration. It's caused by the growth of air-borne algae which deposits on your roof. The good news is that algae growth does not affect the service life of your roofing material. It occurs most often in warm, humid climates such as the Southeast (where algae-resistant shingles are available).
Curling
Curling is caused by a number of conditions including: high nails, lack of back coating, under-saturation of asphalt felt in organic shingles, lack of ventilation and improper number of fasteners.
Blistering
Blistering is caused by moisture in the shingle.
Missing Shingles
Damaged Flashing
Damaged flashing is caused by: improper installation on a new roof, drying and cracking on an old roof, dents by improper nailing, and settling of the structure
Buckling
Buckling is caused by: improperly applied felt, wrinkled underlayment, roof deck movement, spacers not used in between roof deck boards, poor roof ventilation and new shingles applied over old, rough shingles.
Rotting
Rotting is caused by absorption of moisture by the mat at the core of the shingle. This is a common problem with organic-based shingles.
Ceiling Spots
Spots are caused by leaks in the roof.
Missing Granules
Normally a certain number of granules will be loose, especially after application. These granules are called "riders" and are a normal result of the manufacturing process. Granule loss does not affect the service life of the shingles unless granules can be seen missing on the surface of the shingles, thus exposing the asphalt or Fiberglas® mat.


