Concrete Masonry Designs
Concrete masonry was chosen to play several major roles in the new building.
Location: Arlington, Virgina
Architect: Bowie Gridley Architects
Wakefield High School in Arlington, VA, has earned a well-deserved reputation for academic achievement and vibrant music, theatrical and athletic programs. The building also serves as a vital community resource, providing an aquatic center and auditorium that hosts a range of
Arlington Public Schools (APS) is deeply committed to energy and environmental conservation, and has been a leader in incorporating sustainability into school building design and operation as well as instruction. When it came time for a new Wakefield, APS set a goal to reduce energy use, reduce water runoff that impacts the nearby Four Mile Run stream, generate energy on site, provide excellent indoor air quality, effectively use daylight to improve the indoor environment and reduce electrical lighting needs. Concrete masonry was chosen to play several major roles in the new building. APS was confident that masonry was appropriate for an educational environment and had the ability to fit a wide range of intersecting design and sustainability goals. In addition, the project was bid as a fixed construction cost, and both the designers and the school system appreciated masonry’s economy.
Concrete masonry for an improved acoustic environment
Wakefield’s new 635-seat auditorium will host concerts, plays and school community meetings in a state-of-the-art setting. In addition to overhead acoustical panels near the stage, the room has painted, smooth-faced concrete masonry walls on either side, and special sound-absorbing acoustical block for the rear wall. The smooth painted surface on the side walls helps reflect sound to the rear of the auditorium, providing a more even sound distribution throughout the space. At the rear of the auditorium, the goal is sound absorption: minimizing sound reflection to eliminate echoes that could interfere with the quality of the audio experience. For this reason, the back wall features acoustical concrete masonry units with an opening molded into the face shell. The opening allows sound energy to readily enter the masonry cells, where it is further dissipated via metal septa and/or fibrous fillers. Concrete masonry walls are often used for their ability to isolate and dissipate noise. In Wakefield’s cafeteria, fluted, split-faced concrete masonry is used for both aesthetics and sound control. The room incorporates units with a rough surface texture and vertical scores in both accent panels and accent bands. In addition to providing visual interest, the split ribs provide increased surface area to help dissipate sound and minimize sound reflection.
High-impact hallways
High school hallways take a beating, so concrete masonry was also used for its durability, low-maintenance requirements and aesthetics. Higher profile hallways sport ground-face concrete masonry: units were burnished after manufacture to achieve a smooth finish, which provides the rich appearance of polished natural stone. The wide range of available colors meant the designers could incorporate the Warrior’s school colors: the walls are white with accent bands in two shades of green. These ground-face surfaces are virtually maintenance free— they will never require painting and are easy-to-clean should the need arise. Using paint-free surfaces also contributes toward the school’s indoor air quality goal, since fresh paint is a major potential source of volatile organic compounds (VOCs).
Recycled content
The standard concrete block and the architectural concrete masonry units used throughout the project incorporate recycled materials. The inert nature of concrete masonry lends itself well to incorporating recycled materials as cement replacements, as aggregates and as other constituents in the concrete mix. When concrete masonry products incorporate recycled materials, the units must meet the same ASTM unit specification as those without recycled materials. These standards contain minimum requirements that assure properties necessary for quality performance.
Construction waste management Wakefield’s previous building is undergoing demolition now. The process is being tightly controlled to maximize material reuse and minimize the amount of debris delivered to landfills and incinerators. The concrete masonry in the old high school will be salvaged from demolition, and can readily be recycled into aggregate for road bases or other concrete products, pipe bedding or construction fill. In addition, during the construction process, saw-cut scraps and broken pieces of concrete masonry can be crushed and reused. Intact, unused concrete masonry units can be redirected to other projects or donated to charitable organizations such as Habitat for Humanity.
Regional materials
Using materials and products that are locally extracted and manufactured utilizes indigenous resources and reduces transportation needs and its environmental impacts. The LEED requirement is to “specify that a minimum of 10 percent of building materials be extracted, processed and manufactured within a radius of 500 miles (805 km).” Concrete masonry materials are most commonly extracted and manufactured close to the jobsite, thus helping to fulfill this LEED credit. The block for Wakefield traveled about 20 miles (32 km), well within the 500-mile (805-km) radius required to earn this LEED credit.
Photos courtesy of Bowie Gridley Architects
