Landscape Contractor / Design Build Maintain

SEP 2017

LC/DBM provides landscape contractors with Educational, Imaginative and Practical information about their business, their employees, their machines and their projects.

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Page 9 of 71

The new apartment building took up all allowed impervious space, so no additional impervious surface areas were permitted within the garden. Finding the right permeable material for the pathways and patio, and meeting requirements to retain storm - water on site, presented difficult problems. "The average age of Samuel A. Green residents is 80. To get out and enjoy the garden, they need a solid, stable, non-slip surface that is easy to navigate with walkers and wheelchairs. That ruled out gravel," said Sykes. "The paving material also had to have more porosity than permeable pavers. Otherwise, we would have been forced to install additional stormwater retention features at grade, adding costs and detracting from the landscape." Sykes considered Porous Pave XL, a highly porous and durable pour-in-place paving material made from 50 percent recycled rubber chips and 50 percent kiln-dried aggregate mixed with a liquid binder, as a possible solution. He had completed training at Aquarius Supply, Norristown, Penn., to become a certified installer but had not yet had the opportunity to use it. "With 27 percent void space, the material infiltrates more stormwater than permeable pavers," said Sykes. "It forms one continuous, consistent, solid rock-rubber permeable surface, and the rubber content gives it good traction while making it freeze- and frost-heave resistant to eliminate the risks of heaving and cracking." Sykes and a five-man crew installed a total of 1,650 square feet of permeable walkways and patio. As the first step, they put down and compacted a four-inch base of crushed aggregate. Then they batch mixed the granite rock and rubber chips with the binder in a portable mortar mixer. Every 50-lb bag of rock plus a 50-lb. bag of rubber, mixed with five quarts of binder, yielded 16 square feet of material for installation at a 1-1/2-inch depth. Sykes advises careful measurement of the binder so the exact same amount is used in each batch. "It was easy to install and finish with bullfloats and trowels," said Sykes. "I already specified it for another job." "The garden is a place of beauty and peace, and the pavement makes it accessible and safe," said Jane Lahage, NAHP-e, direc - tor of operations, Federation Housing, Inc. "The color and tex- ture of the material complements the building and blends with the landscape created by Garrett Churchill." LC DBM 10 LC DBM Above The site where the garden is located had an old mansion that Federation Housing, the property managers, had hoped to keep and renovate. But it was too costly. To get permission from the town of Elkins Park to demolish it, they had to agree to maintain it in perpetuity as green space for the use of everyone in the town, not just residents of the new senior apartments. Garrett Churchill, Inc., saved and used some materials from the old house in the garden, including this column. Left & Inset Due to permeable surfacing regulations, and because many elderly residents of the Samuel A. Green House use walkers or wheelchairs, a permeable surface that is also ADA-compliant was required for the garden paths and patio. The Garrett Churchill team used Porous Pave XL batch mixed on site and poured in place at a depth of 1.5 inches atop a four-inch base of compacted crushed ag- gregate. Once installed, the surface cured within 24 hours. Hardscapes continued from page 8

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