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Award, which honors the excellence of a project team in bringing a de-signer’s vision to life. The same year, Sunset magazine chose one of the Bel-gard’s permeable paver systems for a 2,800-square-foot pedestrian deck as part of the construction of its annual “Idea House.” The Sierra Paciﬁ c building is in a very densely populated commercial and urban area, a block from the busy 101 freeway in Los Angeles. It may not rain often in southern California, but when it does, the daily rainfall can be more than 4 inches. Most of the stormwater on the building’s site comes from onsite. Stormwater runoff from the park-ing lot contains the pollutants that are typically found on parking lots, including hydrocarbons, sediment, and heavy metals. All the runoff used to ﬂ ow into the municipal storm sew-er system and from there to nearby beaches, which often were closed be-cause of water pollution. The entire parking lot is 14,000 square feet. “The portion we did was the actual parking spaces,” says Gerber. “There are 39 of them in the outdoor parking lot. We laid 5,000 square feet of Belgard’s Aqua Roc Pavers.” All Construction of Simi Valley, CA, demolished the old parking lot, crushed and recycled the concrete, and installed a drainage system that ties into the municipal stormwater system. Crews poured the concrete driveway and curbs to provide solid borders for the pavers. “All the concrete work had to be done before the paving stones because the exterior borders of the pavers have to be set up against concrete borders or wet-set in concrete,” explains Gerber. “That prevents any lateral movement of the stones.” About 75% of Gerber’s work is laying paving stones, but this was the company’s ﬁ rst time laying permeable pavers. “The fact that we hadn’t done it before meant a little bit of a learning curve,” he says. “We had a trial run on one parking stall to see how much the stone would settle when it was compact-ed. That way we could ﬁ gure out exactly how high to set our ﬁ nal grade.” Gerber excavated twice as deep as required for the concrete driveway, ap-proximately 14 inches, to create a ba-sin for the stormwater to sit and slowly seep into the soil. Crews created a layer approximately 6 inches deep of 3-to 4-inch crushed rock, a middle layer ap-proximately 3 inches deep of 1 1/2-to 2-inch rock, and a top layer approxi-mately 2 inches deep of 3/8-inch rock. They graded the surface to direct any runoff to storm drains. “It has to be crushed rock so the jag-ged edges lock together,” he says. “You want to end up with about 11 inches so the paving stones can take up the last 3 inches or so.” These stones are 3 1/4 inches, or 80 millimeters, thick and have spacers on them that set them approximately 3/8 inches apart to be ADA compliant. Ger-ber set them as level as possible on the top layer and then went over them with a compacting plate. “When you go over the stones with a compacting plate they’re really smooth,” he says. “Then you put sand between them and vibrate it in. You can drive on them that night.” Because concrete is porous, the pav-ing stones will absorb oil leaking from cars, he says. “There’s a sealer that can be applied on the stones that keeps oil from sitting on them. One kind doesn’t change the color and the other makes them look wet. If oil sits on anything for a week or two it will permeate, but the sealer will help.” The entire project took about eight weeks. It was completed in the end of December 2011. “It was a great project,” says Ger-ber. “We did 5,000 square feet times 14 inches. That will hold a lot of water. We’re so dry all the time in southern California; we need to put as much water into the ground as we can.” Janet Aird is a California writer specializ-ing in agricultural and landscaping topics. Scan here to share this article or read later. Get the app at http://gettag.mobi 32 June 2012 www.stormh2o.com

Stormwater June 2012 : Page 32

Pine Hall Brick

Pine Hall Brick