Product Profile: Pine Hall Brick
The company has always claimed that StormPave® genuine clay pavers from Pine Hall Brick work well as a surface for a parking lot. But officials in Annapolis, Maryland, found that they efficiently drained rainwater from a 100-year storm, help with archaeological research, and can even help prevent pedestrians from slipping and falling.
The story starts in September 2010. Annapolis was hit by the remnants of Tropical Storm Nicole and its accompanying deluge of more than nine inches of rainfall in a 24-hour period, which a National Weather Service hydrologist ranked as between a 100-year and a 200-year rainfall. (That means that there is a chance of between 1/2 percent and 1 percent of that much rain falling in that length of time in any given year.)
The rain fell in torrents onto the parking lot of the Annapolis & Anne Arundel County Conference and Visitors Bureau Visitors Center, which was paved with StormPave® permeable clay pavers from Pine Hall Brick Company. From there, the rainwater promptly disappeared. (Take a look!)
Landscape architect Shelley Rentsch, ASLA, principal of the O’Doherty Group (www.odohertygroup.com), which oversaw the design of the installation, said the 10,000-square-foot parking lot directs rainwater underground to six rain gardens that are on the edge of the property. From there, the water goes to an outflow pipe. Rentsch said that Tropical Storm Nicole has been the only time that any drainage has come from that pipe, and then it was only a trickle.
The $795,000 project was funded mostly through a federal grant from the American Recovery and Reinvestment Act through the Maryland Department of the Environment. The Baltimore Sun reported that the city paid $64,000.
Rentsch said the project’s goal was to create a green parking lot that was welcoming to visitors to the city while at the same time complementing the surrounding historic district, which is made up of red brick buildings, some of which date from Colonial times.
“We went about it to create a people place, and it was more about that than it was about the engineering,” said Rentsch. “The aesthetics, the engineering, and the environment should come together every time.”
The pavers are a close first cousin and virtually identical in appearance to Pine Hall Brick's popular English Edge pavers, which have been chosen by landscape designers for years for their permanence and aesthetic appeal. Similarly, a sister product, RainPave, looks like Pine Hall Brick’s Rumbled line, which is intentionally distressed to look like old reclaimed brick.
But unlike conventional clay pavers, these pavers have a larger joint between them—a higher void area—that allows water to infiltrate through the pavement surface and dissipate into the soil.
And underneath the pavers, instead of a conventional paver installation that includes a bed of crushed stone and sand, with sand swept into the joints on top, there is a series of “open graded” aggregates, gravel without fine particles, used as base and joint material.
After excavation, the soil is compacted. The largest stones are used as a subbase (#2 stone), with a medium layer on top of that (#58 stone) and a finer layer (#8 or #89 stone) as a bed for the pavers as well as for joint material. The series of open aggregates allows rainwater to flow, as good bacteria build around the rocks over time and aid in diminishing some of the pollutants.
Another advantage of the permeable pavers is the potential to qualify for LEED credits in five categories: Stormwater Design, Heat Island Effect Nonroof (Red, Rose, Gray, Siesta, and Buff colors), Recycled Content (Rose and Siesta colors), Regional Materials Manufactured, and Regional Materials Extracted.
In a way, the StormPave installation in Maryland has even contributed to the area’s history. Excavations at the job site led to the discovery of two privies owned by Charles Carroll of Carrollton (1737–1832), a wealthy Maryland planter who was an early advocate of independence from Great Britain and the last surviving signer of the Declaration of Independence.
Lily Openshaw, project manager for the City of Annapolis, said that thousands of cataloged artifacts were recovered as archaeologists worked alongside paver installers.
“We came up with a monitoring plan, which identified what we considered the hot spots, and we scheduled for their field person to be out at the site when the contractor went into those areas,” said Openshaw. “When she would find something she would have them move. I think we stopped one full day (of installation), but we were able to work with them on staging and let them keep working.”
The bonus is that the engineering design kept the paver installation above the existing grade, which preserved as much of the undisturbed soil as possible.
That means that any artifacts remaining in the ground will remain as they have for the past two centuries. Additionally, it is relatively easy to remove clay pavers, set them aside, and then put them back, which means that researchers could conceivably come back and do further archaeological digs in the future.
Openshaw said the installation has had one unexpected bonus: no ice.
In the past, the parking lot was paved in asphalt. In winter, it would typically rain and the water would puddle up and then freeze. Sometimes the city would have to rope off the parking lot to keep down the possibility of fender benders and falls to the pavement.
Openshaw said that this winter when it rained, the water went into the ground and the brick pavers dried out. There was no standing water and no ice.
“It has performed better than expected,” said Openshaw. “This is fabulous, it really is, and it looks beautiful, too.”
About Pine Hall Brick: Founded in 1922, Pine Hall Brick is a family-owned company and is a leading manufacturer of face brick, pavers, and special-shaped brick. The company is the largest supplier of clay pavers in the United States. Headquartered in Winston-Salem, North Carolina, the company has three plants in Madison, North Carolina, and two plants in Fairmount, Georgia. The company has 150 distributors in 38 states. More information can be found at www.pinehallbrick.com or www.americaspremierpaver.com, and at our blog at www.pathwaycafe.com.