 Author: Tim Trombley ,Owner of Shelby Construction Services Why do some roofs last 50 years and others only 10-15? Aside from the obvious differences in material quality, and installer experience, one of the single biggest factors in the lifespan of your new roof is how well it was ventilated. We have seen “50 year” shingles fail after only 10 years, and conversely, we have seen 25 year shingles that have been on the roof for over 25 years and still look great. Why is this? The answer, in most cases, is how well the roof is ventilated. There are several causes for premature shingle deterioration but the most common is granule loss. Summer months: The shingle granules not only give the shingle it’s color but also protect the asphalt in the shingle from UV exposure. UV rays start to break down the asphalt in the shingle and cause the aging process of the shingle to significantly speed up. When attics are not properly ventilated the attic temperature can soar to as high as 140 degrees in the summer. These high temperatures cause the asphalt in the shingle to soften, which in turn loosens the granules on the shingle and then the next rainfall washes away the loosened granules. One way to tell if your roof is losing granules is to check the end of your gutter spouts to see if granules are being washed away or check inside the gutters to see if there are roof granules in them. These extremely high attic temperatures can also cause the shingles to curl. Winter months: Attic ventilation is especially crucial in colder climates. In colder months when the furnace is in use, some of that heat rises into the attic and if not ventilated out, that causes the attic temp to rise. That then causes the snow on the upper sections of the roof to melt and run down to the colder eaves and re-freeze, creating an ice dam. The more this process occurs, the larger the ice dam grows. Large ice dams can trap standing water which eventually will find a way to penetrate the roofing materials and cause leaks and water damage to the interior of the home. Also, when the attic temp is 60 degrees, and the outside temp is below freezing, that difference in temperature from one side of the shingle to the other side causes granule loss. Moisture: The average family of 4 produces 2.5 gallons of water vapor per day. Showering, cooking, breathing, plant life and pets all produce humidity/water vapor. That warm water vapor rises into the attic and if not ventilated out, can accumulate on the underside of the roof decking. This can lead to mold in the attic, rotted or warped roof decking and wet insulation. Mold in the attic can cause an array of health problems and can be particularly dangerous to those with breathing problems such as asthma. When choosing a roofing contractor, make sure he or she is well versed and trained in the nuances of roof ventilation. Ask the contractor to share with you their ventilation calculations. Building codes have established a formula to determine the exact amount of ventilation required based on the size of your attic. Make sure your contractor knows this formula and shares his calculations with you. Proper ventilation can mean the difference between your new roof lasting 50 years or having to replace it again in as little as 10 years. For more info about roof ventilation visit our Roofing page https://www.shelbyconstructionservices.com/roofing.html Comments are closed.
|
Archives
March 2025
Categories |
RSS Feed
