Destin Roofing: Article About Multiple Layers Of Shingles
In terms of roofing materials, asphalt has one of the shortest estimated lifespans. However, asphalt is still one of the most popular materials when re-roofing due to its cost. As such, some homeowners may choose to add a second layer of shingles over the first when re-roofing. While there is some debate over whether or not re-roofing over an existing asphalt roof is a good idea, there are certainly potentially advantages and disadvantages to doing so. If a homeowner is considering re-roofing on top of asphalt shingles, a Destin roofing contractor can determine if their home can support a second roof.
The main advantage to an overlay is that this can save some money. Homeowners do not have to pay to rip up the old shingles and, as long as the underlying components are sound, the new shingles will provide adequate protection.
However, the risks and disadvantages of overlaying an asphalt roof might outweigh any advantages. The biggest issue is that if the shingles are not removed prior to a new roof being installed, it is not possible to ensure that no damage has occurred to the underlayment. If damage has occurred, the roof may leak even with the new shingles.
Another major problem is that adding a second roof to a home adds quite a bit of weight to the structure.
The expert roofers at Art Construction of Destin FL can assist you with any questions regarding residential roofing or insulation.
Most homes are designed to be able to hold more than what the roof weighs; otherwise, the roof structure would collapse if a large amount of snow, ice or water accumulated on the roof. However, installing a second layer of shingles could add an additional 350 to 450 pounds per 100 square feet of roofing. This could ultimately cause the roof sheathing to sag and make leaks much more likely to occur.
Further, shingles are designed to lay flat. When they are applied over a pre-existing layer of shingles, it can be difficult to ensure that the new shingles are positioned to properly drain moisture from the roof. If the original layer of shingles is in good condition, problems are less likely to occur; however, if the bottom shingles are curled, cupped or split, those deformations will translate to the next level.
Ultimately, it not highly recommended to have a second layer of asphalt installed over an existing level. However, all roofs are different, so those who are considering laying a new roof asphalt over the old one should consult with their local contractor before making any major decisions.