What's sustainable about masonry? As masonry construction competes against other building materials, architects, material suppliers, and even masons must have an answer to this question. Project owners are looking for value from every angle, including sustainability.
Clay and concrete brick have many environmentally friendly features. Brick's durability reduces the need for repair or replacement (and associated materials) over a structure's lifetime. Even after the structure outlives its original purpose, brick can be restored or reused.
Brick's thermal mass makes it energy-efficient. Its passive heat gain helps naturally regulate indoor temperatures, meaning less energy is used for interior temperature controls. Masonry helps improve indoor air quality by creating a breathable, mold-resistant building envelope. And brick is attractive enough to replace drywall, paint, and other volatile organic compounds (VOCs) as a finished interior surface.
Brick producers are increasing their manufacturing efficiency. According to the Brick Industry Association, it takes almost 70% less energy to make brick today than it did in 1970. The association reports more than 80% of brick kilns are fired with natural gas, and many facilities use alternative fuel, such as methane gas and sawdust.
Producers are finding ways to conserve raw materials. Hanson Brick, based in Charlotte, N.C., reuses un-fired waste brick and other nonhazardous waste, such as ceramic tile or pots, bottom ash from coal-fired power plants, and waste scrubber lime as raw materials for new brick. Through its Brick Back Program, the manufacturer accepts brick construction waste, which can be used for existing products or landscaping material. Or, it can be ground with bulk raw shales and clays to be used as raw material. Hanson and other brick makers are also reducing material usage by making brick with larger voids.
Concrete brick producers are using recycled materials to reduce the embodied energy, or carbon footprint, of their products. Calstar Products in Newark, Calif., produces brick with 40% fly ash from power plants. This keeps waste material from landfills, while reducing producers' reliance on new cement and its associated energy consumption.
Where credit is due
Unfortunately, brick and other masonry materials are not getting credit for all of their green benefits in sustainable construction rating systems, such as LEED (Leadership in Energy & Environmental Design). In March 2010, Shahnaz Jaffari, director of sustainability for the Rocky Mountain Masonry Institute and a LEED accredited professional, published “Concrete Masonry in Green Buildings: Award Winning Architects' Perspective.”
In the study, sponsored by the National Concrete Masonry Association, Jaffari interviewed 24 building experts who used concrete masonry in green projects. Her interviews revealed that, “design teams chose concrete masonry for its inherent green attributes, some of which have not been recognized by LEED and other rating systems.”
Architects who designed with masonry earned LEED credits for using regional materials in about 33% and recycled content in 28% of the projects covered in the study. However, LEED does not currently give credit for passive design, long service life, fire resistance, minimal maintenance, resource efficiency, mold prevention, and VOC reduction through material selection.
Jaffari urges further research into the choice of green building materials and how they function. “Concrete masonry has been a popular building material for centuries because of its inherent green qualities and needs to be justly recognized for them,” she concludes.
The International Masonry Institute provides a list of potential credits.
by Shahnaz Jaffari
By Patrick Kelly & Tiffany Ward, Hanson Brick