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Challenging Irrigation on Two Levels

By Gabriel Lefrancois, regional editor

Schedule 80 PVC lines the rooftop plaza, which shows multiple levels of sodded lawn areas, planter beds and random-patterned blue stone with sod joints. Lipinski Landscape Irrigation Contractors worked with the masonry contractor to map out the spray head locations.

Lipinski Landscape Irrigation Contractors of New Jersey took the challenge of irrigating the new Wharton School of Business at the University of Pennsylvania. What began as a challenging job, turned in to an extremely complex and laborious endeavor. In order to complete the landscape and irrigation work, Lipinski had to coordinate with numerous building trade contractors, while maintaining the strict time restraints of an accelerated completion schedule.

Located in an urban, public environment, the site was broken into two primary areas: one at street level and the other on a rooftop terrace.

On the Ground

At ground level, the Lipinski team mainly used a drip irrigation system, which encompassed raised planters, vine plantings and trellises along with some four-inch popup spray heads that covered turf areas. Adding to the hardscape surface, eight Bloodgood London plane trees planted in tree pits enhance the outdoor cafe and provide a sense of scale to the surrounding buildings. Although the ground area had a typical drip irrigation system, scheduling problems proved this job far more complex.

David Migill, who sold the job with Debbie Comyn as a product manager, but whom now works as a sales manager, says that coordinating with the different types of contractors was tough. And because the architectural level of the project was so high, everything was extremely detailed. Through daily communication, onsite and daily overall meetings every week, Lipinski and the other contractors were able to put the job together.

“We were dealing with no less than five or six different trades, and the project had an extremely compressed schedule,” says Magill. “Getting the masonry contractor, the concrete contractor and the other trades to finish what they were doing was tough for us to complete the job we had to do. A lot of times, we were working under the lights.”

A raised planter on the roof plaza where honey locust and Pachysandra are planted into the structural soil mixture. Drip irrigation was installed throughout the planter. The workers are installing valve boxes.

Of major concern during the project was a large public seating area with numerous tree pits and vine plantings. With that, construction called for all the sleeving to be installed in advance. As a result, the layout of these areas had to be completed. What followed was a painstaking and laborious process requiring several feet of compacted rubble to be excavated in order for the irrigation sleeving to be placed.

“There was an extensive amount of sleeving – interior and exterior, that ran through the concrete,” affirms Magill. “There was an enormous amount of raised planters and small isolated planting areas mixed in to large areas of concrete and pavers. We had to run the sleeve before all the other hard finish work was done. We really had to engineer out where those open areas were going to be, making sure the sleeve started and stopped in those open areas.”

Since everything was done under final hardscape product pavers and through walls, the Lipinski company found it necessary to use schedule 80 PVC on all main and lateral lines for the entire site in order to prevent brakeage on the heavily traveled areas. And because the grade of piping was less flexible, fishing it through the sleeves made for a very slow process.

As for the other ground level areas, Many of the other ground level areas, drip lines, which had holes spaced eight inches apart, served planting beds and raised planters.

To the Roof

Another challenging part of the project was to irrigate the rooftop garden that stood one and a half stories high. It quickly became the main focus for the Lipinski team and their most challenging task. Confined to a small workspace along with a variety of contracting teams on the roof, the project required extreme planning and attention to detail.

After a concrete protection slab was poured, the Lipinski team put several hundred yards of aggregate material (a lightweight planting mix) on the roof via a 72-foot roofing conveyor. In that mix, a maze of irrigation lines were placed under the free laid bluestone with sod joints. This took careful planning because each head had to be precisely placed to coordinate with the masonry contractor.

Four-inch popup spray heads were employed to irrigate the rooftop plaza lawn area.

“The vast majority of the patio was the bluestone,” says Magill. “It made that part of the job the toughest and probably the most difficult all around project we worked on because we had to plan ahead of where the bluestone was going to be.”

Adding to the projects complexity was a pressure test. Magill says that because so much of the project was under finished product, Lipinski was required to do an air pressure test, and in order to pass, the system of pipes had to hold 120 lbs. of pressure for 24 hours.

“We took an air compressor and put a guage on the system,” says Magill. “Without heads, you put your core piping in the ground and you glue it all together. Then, with a pressure gauge attached, you fill the system with air. If it’s done correctly, the system will hold that pressure for 24 hours. Those were some nervous moments.

After the pipes were laid, water was run through the entire infrastructure of the building to reach the one and a half story rooftop, which encompassed drip and normal spray type irrigation. And since the water source and irrigation controller were located in a mechanical room on the opposite side of the building, the Lipinski team had to weave the water feed and control wires through the structure of the building as well.

Times of utter anxiety would soon be moments of complete satisfaction. The Lipinski team had passed their most challenging task with flying colors. Soon, six honey locust, 11 Columnar Siberian crabapples and 4,500 square feet of sod would all be craned onto the rooftop and installed.


If irrigating the rooftop garden wasn’t complex enough, the drainage system was an elaborate system in itself. American Hydrotech, a company specializing in rooftop gardens and drainage systems, manufactured the products Lipinski used to drain their elaborate irrigation system. The design allowed water to drain between planters and hard surfaces.

Plastic sheets of Root Stop, roughly 4-by-6, were laid on top of the newly pored concrete slab. Described by Magill as a “giant egg carton,” the Floradrain is a three-dimensional panel that has retention cups on the topside, drainage channels on the top and bottom and holes in the tops of the domes for ventilation and evaporation. A clay type brick is put into the depressions for further water absorbent capabilities. Finally, a fabric made of non-woven, non-rotting polypropylene fibers is laid down on top to keep the clay brick clean from the soil.

“The water moistens and percolates through the expanded shell product,” says Magill. “Then it filters down through the clay, which then retains the moisture and creates a wick effect through the expanded shell product. Any other water will percolate through the egg carton type material, cascade along the concrete base and drain to the appropriate places.”

Pete Haran, Lipinski’s vice president, was satisfied with the project, but says the school could of saved on their budget had they not over speculated many of the materials.

“On a rooftop garden, with a sophisticated drainage system, the need to make sure the system is not going to have a break in it that would add additional water to the drainage system is a concern,” says Haran. “Sure, that is important, but it was probably over spec’d to a point where it could have saved them money.”

Back Down to the Ground

Through hard work and vigorous planning and scheduling, the Wharton School of Business now has a beautifully landscaped environment and surroundings for the students, faculty and alumni. When asked what other trades could learn from a project like this, Magill says, “You can’t over emphasize the importance of pre-construction coordination and pre-installation coordination. Our lives a lot easier if we would have know things in advance.”

Project Name:
Wharton School of Business

University of Pennsylvania

Irrigation Company:
Lipinski Landscape Irrigation, Inc.

Type of Irrigation:
Drip line spaced across planting beds or over raised planters. Rotors, spray and drip irrigation for lawns and planters


  • Schedule 80 PVC
  • 450 cubic yards of lightweight soil medium (rooftop)
  • 104 tons of clay brick chips (rooftop)
  • 6 Honeylocust, 4-4.5" caliper (rooftop)
  • 11 Columnar Siberian crabapples, 3-3.5" (rooftop)
  • 4500 square feet of sod (rooftop)


  • American Hydrotech
  • Root Stop WSF 40
  • Moisture Retention Mat SSM45
  • Floradrain FD60
  • Systemfilter SF

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December 9, 2019, 11:23 am PDT

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