March 24, 2017
Guide to Understanding Roof Shingles – Part 2: Common Questions From Our Customers
Question: Does a heavier shingle mean that it is better quality?
No, a heavier shingle does not mean better quality. Weight is only one factor that affects the quality of a shingle, other factors include resistance to tearing and asphalt quality.
Question: Do dark-colored shingles increase the temperature on the surface of a roof?
Yes, dark-colored shingles are made of materials that absorb more heat than lighter-colored shingles. This temperature can vary by 20-50 degrees centigrade in some cases.
Question: How can I keep my attic cool?
Asphalt shingles play a large role in heating the attic. They have less reflective properties and therefore absorb more solar energy from the environment. As a result, the temperature of the rooftop will increase and the trapped solar energy will radiate downwards to the attic and living space. Here are three ways you can keep your attic from overheating:
- Install Proper Ventilation: The temperature of a properly ventilated attic can be as much as 20 degrees centigrade lower than that of a poorly vented or unvented attic.
- Use Solar Reflective Shingles: Many manufacturers offer patented solar reflective shingles. They are designed to reflect solar energy back into the atmosphere and are more effective at reducing heat transfer than traditional asphalt shingles.
- Install a Metal Roof: Similar to solar reflective shingles, metal roofs are highly reflective and can reduce heat transfer by reflecting solar energy back into the atmosphere. Metal roofs have an initial solar reflectivity of 0.68, and an emittance of 0.86. The solar reflectivity of asphalt shingles is usually lower than metal roofs. However, some shingles may have comparable or higher ratings in their emittance.
Question: Why is a roof-over a bad idea?
By allowing the original layer of shingle to remain, the most obvious advantage of a roof-over is its reduced cost. However, a growing number of roofing contractors do not recommend this method as they can lead to poor results and further problems in the future.
When performing a roof-over the condition of the roof deck cannot be observed. Rotted roof decks may not be detected and some affected areas may not provide good anchorage for nails. Our experience has told us that roof-over jobs may increase workmanship errors, especially when the conditions of the roof system components (such as flashings) are uncertain. At Safe Roofing, we believe the best practice is to perform tear-offs before installing new shingles.