Green roof installation calls for training on using ropes and harnesses, and learning how to scale up and down a building.
Photos courtesy of Jensen Landscape

The green roof business didn’t exactly sprout overnight at Jensen Landscape in San Jose, California. It started with a single project in 1995 for The Gap in San Bruno. The company had never taken on anything like this before, but a general contractor on the job planted the seed and John Vlay, CEO, pulled together a budget.

“A designer came up with the plant palette – mostly native California varieties – and we overseeded the 70,000 square foot roof,” he says.

The project didn’t scare off Jensen Landscape, Vlay says, “We have always liked to get into different things – things that might scare other people to us is just landscaping. We were familiar with planting concrete pots, which basically have a drainage layer at the bottom, soil mix, plants and irrigation. So I figured we’d do the same thing for the green roof.”

Of course, it wasn’t that easy. But with careful planning and a skilled team, Jensen Landscape successfully pulled off that first project. After that, green roof projects trickled in. “We did start to see more of this work,” Vlay says. Then in 2007, the firm wash hired to install a 100,000 square-foot green roof on the California Academy of Sciences, which includes a surface of domes that called for planting at a 45-degree angle.

Now that was a different project. But by then, Jensen had traded wheelbarrows for conveyers for moving soil when possible, and the team had a good decade of experience with green roofs by then. Here’s what Jensen Landscape has learned after a couple dozen green roof projects – a piece of the business that represents an annual revenue anywhere from $200,000 to millions of dollars.

Budget ‘high.’

Because green roof projects literally elevate a typical landscaping job (and the sheer height drives up risk), Jensen Landscape is careful to figure in the extra time and safety considerations required when working on top of a building’s structure. For that first project, Vlay figured the cost of using a crane to move plant material from the ground up. Then, they added plant material and labor.

Every green roof job is different. “It’s a matter of figuring out on the job site how you want to get it done,” Vlay says. “Foremen help us come up with new ideas for getting jobs done as efficiently as possible.”

Get creative.

The crane that Jensen Landscape rented for the first green roof project had a large bucket to move soil from the ground level up to The Gap’s roof. “We custom built the bucket so it would hold a lot of soil, and then we could just open it and the soil would, for the most part, fall into four wheelbarrows that were positioned beneath it,” Vlay says.

All soil was loaded near the edge of the roof, then hand-moved to the center until the space was filled. Actually, production was moving faster than anticipated. The superintendent on the job called for three more wheelbarrows to keep up with the soil spreading. “That cut down the time even further,” Vlay says.

The safe way.

Green roof installation does not require special insurance coverage for the business. But it does demand training for using ropes and harnesses, and learning how to scale up and down a building. The team meets regularly to share experiences and swap ideas. “We are always looking to learn and we’ll take any advice or suggestion from anyone, whether it’s a laborer or superintendent,” Vlay says.

The after-care.

After The Gap installation was complete, Jensen Landscape maintained the green roof for one year. Then, the firm was price gouged out of the contract – and the roof essentially failed under the care of two different contractors. Vlay got a call. “They came back to us to replant it and maintain it,” he says.

Jensen Landscape figures in the extra time and safety considerations required when working on top of a building’s structure. Foremen help come up with ideas to be more efficient.

“We always give clients a permanent maintenance proposal when we are finished with installation because you can’t just let anyone maintain (the roof),” he says. “It has to be constantly monitored, fertilized, irrigated.”

Projects generally have a post-installation maintenance period of 90 days to a year included. And Vlay says that after hearing The Gap story, most clients choose Jensen Landscape to care for their roofs long-term.

The best part.

There is growth opportunity in the green roof business, with more landscape architects specifying this type of work, Vlay says. Because Jensen has a track record in this department, “we have a pretty good opportunity to bid and get jobs.”

What Vlay and his team like about this work is the variety and challenge. “It’s more complex, which is to me, what’s fun,” Vlay says. “You’re always reinventing the way you do things.”