Water World: On the grid

June 3, 2019 - By Danielle Pesta

Location Louisville, Ky.

The University of Louisville’s Novak Center for Children’s Health is home to a multilevel green roof. The installation on the fourth and eighth floors includes a well-thought-out irrigation system.

Alex Fransen, president at Fransen Group, says due to its height, the green roof is susceptible to higher winds and a loss of precipitation. Avoiding sprayheads prevents hard-to-reach exterior windows from needing to be cleaned, he adds.

To combat a loss of water from sprayheads due to wind, Fransen says his crews installed drip irrigation.

Built on a grid pattern, the system has a drip emitter and drip line 12 inches apart. Installing drip irrigation solves water challenges by allowing adequate moisture to reach the plants’ root zone.

In total, the green roof spans more than 3,500 square feet. Fransen’s team installed everything above the waterproofing except for plant material. A local arboretum donated and installed native wildflowers and perennials.

Fransen says he helped oversee the plant installation according to irrigation needs. “I determined the water requirements based on plant materials and light on the rooftop,” he says.

Two smart controllers with Wi-Fi and rain sensors monitor the drip irrigation on the roof. The Rain Bird controllers act like “mini weather stations,” according to Fransen.

Photo: The Fransen Group

LINED UP Before the Fransen Group could begin the project, a roofing company installed waterproofing. Because of the need to coordinate with other trades, the company completed the project over two and a half months.

Photo: The Fransen Group

GREEN CERTIFIED Alex Fransen and his company have been installing green roofs for more than 11 years. The company is certified with American Hydrotech, a green roof manufacturer. Besides drip irrigation, crews also installed American Hydrotech green roof materials for this project.

Photo: The Fransen Group

ROOFTOP VIEWS The project was completed in late summer 2018, so this will be the green roof’s first full growing season. The local arboretum is volunteering to help with the first year of maintenance at the site, after which, the Fransen Group will take over.

Photo: The Fransen Group

WEED WATCH Weed pressures begin right away. So, Fransen says early maintenance is key. He even makes sure to detail the specific maintenance requirements with the owner in the project contract.