Asphalt Shingle Granule LossAuthor: Pacific Northwest Inspections Group, LLC Date: 19-Nov-2013. Category: Roofing Add to Favorites
It happens to all asphalt roof systems just before the product begins to fail. Asphalt roofing materials do not hold up to direct UV exposure so to protect the material Shingle Manufacturers use small colored stone chips called granules to protect the asphalt from environmental elements and to provide an esthetically pleasing look to your roof cover system. Over time these granules will naturally wear off and when this occurs the asphalt surfacing begins to break down causing a downward turn in the shingle’s life. This is the main reason why we do not recommend to pressure wash a shingle roof. Pressure washing dislodges the granules from their asphalt embedment reducing the products life span greatly. We also have found improper ventilation to be a major cause of premature granule loss. It is also important to keep overhanging trees trimmed back so they don’t brush off granules. Thirdly walking on the roof system especially when its in the hot sun can damage the grails as well. Photo shown is an example of granule loss and the starting of shingle breakdown. This is a sign that roof replacement is very near. Also when you have your gutters cleaned be on the lookout for excessive granule loss debris. Granule loss is an indication that the intermat fibers will soon be visible and roof replacement options should be considered.
Shingle construction starts with a fiberglass or organic intermat. During production the intermat is saturated with asphalt and dried repeatedly until the desired thickness is achieved by the manufacture. This is what determines a 20year shingle from a 40 year. This intermat is not a waterproofing layer but is necessary to keep the shingle from cracking and separating. Over time the shingles surface wears down and eventually exposing the intermat. It is generally accepted by the roofing industry that when this occurs it is time to replace the roof. Without the intermat holding the shingle construction together the shingle can no longer withstand expansion and contraction and will crack, usually allowing seepage. at this point we recommend that you consider replacing the roof or water intrusion issues will become another issue.