Research | Healthy Urban Environments

Summary

Over 75% of North America’s housing has roof shingles, and 90% of those roofs are made with asphalt fiberglass material. Asphalt is one of the least energy-efficient roofing materials because it absorbs and conducts heat from the sun to attics. As a result, consumer demand for energy-efficient roofs is greatly rising. Furthermore, asphalt shingles’ durability is affected by weathering and moisture. They typically age/dry out from the heat, which makes them brittle. With a lifespan of just 15 to 20 years, asphalt shingles annually produce an estimated 11 million tons of waste in the US.

There is a need to better tackle energy storage and extend the durability of asphalt roofing shingles. This project developed a modification of asphalt shingles with an encapsulated aerogel product, called Aerogel Modified Bituminous material (aMBx), recently developed at Arizona State University. HUE expected that (1) aMBx would act as an insulator and make roofing shingles less temperature susceptible and that (2) the modified shingles would in turn offer an improved thermal resistance by reducing cooling and heating loads in homes and buildings—thus potentially reducing the urban heat island effect.

As part of this project, HUE researchers developed a method for incorporating aMBx in roofing shingles and worked with GAF, one of the leading companies in roofing shingles manufacturing, to develop the best approach to fabricate the modified shingles. The team also conducted thermal properties testing; thermal properties of aMBx have shown excellent thermal resistance in asphalt materials. Some data of interest include those particles ranged from 0.1 to 3mm, density ranged from 0.32 to 0.38 g/cm3, and thermal conductivity ranged from 0.15 to 0.20 W/mo K. The modified shingles proved effective in providing thermal insulation and increased durability for asphalt binders and mixtures. HUE conducted modeling simulations as well, using models such as Cool Roof Calculator and Energy Wise to engineer the best possible and most feasible roofing shingle modified with aMBx. These modified roofing shingles offer unique thermal resistance properties, thus potentially providing added value to the end user and society by saving energy, reducing cooling and heating loads during summer and winters, and reducing CO2 emissions. The EPA initiated the use of sustainable practices for mitigating the urban heat island effect with cool roofs and pavements. The market size for roofing material was about $120 billion in 2019 and projected to reach $152 billion by 2027.