Pushing the limits of manufacturers specifications

When choosing a roofing application there is more to consider than manufacture specifications. Not getting your roof application correct could cost you thousands and may even compromise the entire install. Austin Cowell of QE Roofing in Franklin, TN explains the problem.

Over my 18 years of roofing experience I continue to see poor choice of roof application on low slope roofs. This is most common with shingle installation on roofs that are 2 & 3/12 pitch. Manufactures allow shingles to be installed on roofs as low as a 2/12 pitch. There are some additional precautions that are taken in these installations but one thing that is often overlooked is imperfections in the roof surface. It is very common to have variations in rafters. Meaning one rafter may be slightly higher or lower than the next one. Most lumber is not perfectly straight and settling can further this problem. When one rafter is slightly higher or lower the water will now shed to the side rather than straight down a roof slope. When the roof slope is a 2 or 3-12 pitch this means water is already moving slowly and will now enter the key of the shingle. The key of the shingle is joint where two shingles meet. When water enters the key flowing at an angle rather than straight off the roof it will get under the shingle and ultimately to the first nail. Once water is trapped under the shingle it follows the nail hole into the building. This issue may not be apparent until months or even years after the roof is installed. As water enters the roof through nails the roof decking will absorb moisture which will cause nails to back out. As nails back out through the shingles this will further cause leaking. We often see this issue poor application choice on new construction. I believe there are two reasons for this. First, most shingle roofing crews are not experienced with low slope roofing. Often roofing companies will have one crew for steep slope and another for low slope applications. Second, rolled roofing applications are more expensive and do not last as long compared to shingles. Since new construction margins are squeezed, more expensive applications are first to be changed. When the roof pitch falls within the manufacturer specs companies choose a shingle application.

We strive to provide a superior product and install it properly. Contact QE Roofing for a thorough evaluation of your roof system. This includes the attic, ventilation, roof flashings and low slope roofing. We take the time to inspect your home, educate you on issues, and go over installation of all products we would be installing. If you are in Franklin, Spring Hill, Columbia, Nashville, Smyrna, Nolensville, and Murfreesboro and need help with your roof system contact QE Roofing. Call 615-505-7663 today for a free roof evaluation.


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