Roof Shingles – How long should they last and when do they need to be replaced?
There are many factors to be considered when determine how long your shingles should last. The climate, site conditions and roof design have the most effect on shingle life and appearance. A steeper roof design will drain water and shed debris faster. Roof position relative to the sun helps roofs dry faster. Temperature has some effect on roofing shingles. Here in Roscommon Michigan we have hot, short summers with cold winters so roofing materials need to be able to handle expansion and contraction throughout the year. Proper roof ventilation can be a factor. Many times during a remodeling project roof design deficiencies can be remedied.
Wind is a problem around open areas like Higgins Lake and Houghton Lake. Lighter weight shingles may lift with the wind, while heavy weight shingles are stiffer and more wind resistant. The weight of a shingle is usually expressed as pounds per 100 square feet (a square of shingles is 10’ x 10’). The weight typically reflects how long the shingle is expected to last and the manufactures warranty. 245# – 260# shingle is associated with a 30 year warranty. 265# – 285# is a 40 year and 300# and up, a lifetime warranty. Most manufacture warranties are limited and dependent on proper installation.
North facing roofs along with tree branches over the roof encourage algae and moss to grow. Trees trap moisture and a shaded roof impedes drying. The streaking/staining you see on some roofs is caused by airborne algae. Moss traps moisture and debris, slowing the drying of shingles. This will cause the underlying material to decay and will shorten the life of shingles if not removed. Moss is quite easy to remove. Use a scrub brush on a pole and push the brush down the roof only, not up. This will loosen the moss from the shingles. Non toxic cleaners can be used to remove algae stains. A good cleaner might be non-toxic oxygen bleach. Keeping the roof surface wet with the solution for just 20 minutes, then lightly scrub the roof surface, the algae almost always comes off. You may have to apply the oxygen bleach solution several times if your roof is badly stained. Oxygen Bleach is a ‘green’ cleaner as it uses oxygen ions to break apart stains, dirt and odor molecules. There are no harsh chemicals, and it works on just about anything that is water washable. Use care when cleaning roofs. Wet moss/algae is slippery. Try to stay on the dry parts of the roof. Wear shoes with good traction. Manufacturers now make algae resistant shingles.
Barber Construction Inc. looks for the following signs of roof aging during the inspection and evaluation of your roof: curled shingles, missing granules or bald spots, loose or missing shingles and shrinkage between shingles. All are signs that the roofing is nearing replacement. Some areas of a roof will weather or age faster than others. Spot leaks may develop in areas of roof. A well maintained roof should get you close to the suggested lifetime of the shingle. When you do replace your shingles, have all the existing roofing removed and new underlayment installed.
Please contact us at Barber Construction Inc. if you have any questions.