Four newly constructed warehouses at the Maryland Science Center in Baltimore are almost move-in ready, and two more are in progress. Built by St. John Properties, the buildings provide the center with a distinct advantage, both in construction method and in time, labor, and materials.

The project, started in March, called for six new warehouse buildings to be constructed 300 yards from existing buildings. The warehouses were to be rented out for storage to a high-profile tenant with a strict timeline. The buildings had to go up quickly.

Knowing that constructing such a large project so quickly would come with its share of budget concerns, the contractor turned to Ernest Maier Inc., a local block, masonry, and hardscaping supply company, for a solution. As a manufacturer of normal-weight masonry units, Ernest Maier had already worked with Big River Industries Inc., a large producer of expanded clay lightweight aggregate, to develop a lightweight masonry unit called ELite (or extra-light), for other time-sensitive projects.

Brendan Quinn, CEO and president of Ernest Maier, knew that lightweight masonry block would fill the need for a fast turnaround, while staying within budget. The units contain Big River Industries' expanded clay lightweight aggregate, which makes them lighter and ultimately reduces labor and construction time. “Lightweight block increases productivity even at the same labor pace, and workers are typically more efficient because the lighter block is less work intensive,” Quinn says.

Get in, get out

As a result, the contractor used E-Lite 24-inch-long lightweight CMUs supplied from Ernest Maier in place of the standard weight, 16-inch gray units. In doing so, he reduced construction time and labor on this part of the project by 50%. In all, 6600 24-inch-long lightweight units were used for the straight walls and corridors of each of the four 75,000-square-foot buildings. The mason, Mike Campitelli of Mid Atlantic Masonry in Reisterstown, Md., also used several 12-inch lightweight units and a variety of normal weight material for other applications on the job.

The mason benefited from using this alternative in several ways. In addition to getting paid by the square foot, he made money by completing the job faster. The crew also avoided common injuries associated with heavier block.

These are the key benefits of using lightweight masonry units, especially in large jobs like warehouse construction. “The lightweight factor helps contractors complete projects sooner so they can generate revenue from the projects earlier, which is better for the property owners as well,” says Jeff Speck, vice president of sales and marketing at Big River Industries. “If property owners can reduce the number of days it takes to construct a building, it helps them project when it can be rented and begin earning revenue.”

Making lightweight units lighter

The E-Lite units used for the buildings contain 60% Livlite and 28% natural aggregates; the remainder is cement and water. The finest gradation of expanded clay lightweight aggregate (LWA), Livlite qualifies as a reclaimed material, which benefits contractors applying for LEED (Leadership in Energy and Environmental Design) credits.

Together with its sister companies, Parker Block in Delaware and Skyline Brick in Virginia, Bladensburg, Md.-based Ernest Maier produces 9.5 million units annually, ranging from standard weight to extra light. Most of its products contain Livlite, produced at Big River's Livingston, Ala. location.

The quality of expanded clay LWA results from a carefully controlled manufacturing process. In a rotary kiln, selectively mined clay is fired in excess of 2000° F. The clay expands, cools, and is then processed to specified grading. The result is a high-quality, lightweight aggregate that is inert, durable, tough, stable, highly insulating, and free-draining.

Familiar with the process by studying Big River's Q-Lite units, Ernest Maier developed its E-Lite block to provide customers with a unique approach to time-, labor-, and cost-savings. “The lightweight units have better thermal properties, saving property owners money on heating and cooling,” Speck says. “Also, they have superior fire resistance, providing more structural stability, which is an improvement over regular weight material. And they're safer to handle.”