Rooftop prairie: Nokomis family doesn't have to go far to relax

"Water quality and stormwater management are really big values for us," observed Nokomis resident Steffanie Musich as she drinks a glass of water on her rooftop garden. (Photo by Tesha M. Christensen)

When Steffanie Musich sits on her green roof looking out over the rooftop prairie and the tree canopy, it’s hard to remember that she’s in the city.

That sense of peace and relaxation without having to get in the car is exactly what she was aiming for.

The 11-year Nokomis resident, her husband Matt and son live within blocks of Highway 62 and Cedar, surrounded by the constant hum of traffic and roar of airplanes. They’re also close to Lake Nokomis, and have dedicated years to the intricacies of water quality and sustainability issues.

The green roof is an extension of those values, and a way to demonstrate how it can work in a neighborhood.

When Musich read about the green roofs being installed by Omni Ecosystems of Chicago, Ill. they resonated with her. She didn’t want the type of living roof that merely had a sedum tray of close-to-the-ground plants. Instead, she envisioned a prairie.

The problem is that a roof with 1.5 to 2 feet of soil material is heavy – and gets even more so with a load of snow on it. Plus, the costs of a roof like that are typically beyond what a homeowner can pay.

But Omni Ecosystems offered an innovative system using a new lightweight growing medium with a higher capacity for stormwater management, which allows them to build lighter green roof systems that require less structural capacity. Omni’s projects include the O’Hare Terminal 2 Concourse, Harvard Business School, Chicago’s Wild Mile, and McDonald’s corporate headquarters.

The 300-square-foot green roof at the Musich residence cost about $17,000. That doesn’t include the cost of replacing the garage or the flat roof that is underneath.

While the initial cost is higher than a regular roof, the Musich family believes the positive impacts on their mental health, the extended life of the flat roof beneath it, and the environmental impacts are worth it.

It was 2015 when they began envisioning the project. The couple hired Craft Design and Build from Uptown Minneapolis as the general contractor, and Jody McGuire of SALA Design as architect. Steffanie and Matt saved on costs by doing much of the construction themselves, including all the painting, stucco, and finishing work, putting in time in the evenings and weekends. For the rest, they refinanced and rolled the cost in.

It is important to them that the living roof will last 50-100 years, 3-5 times longer than a traditional roof.

The green roof doesn’t heat up as much in the summer, and it provides insulation in the winter. “Green roofs help with urban heat island effects,” observed Musich.

Bonus: brewery space and sauna

The two-car garage on the property was rotting and didn’t have footings under the cement slab. So they tore it down and started from scratch. The new three-car garage uses three sets of three tri-lam beams made of manufactured wood to distribute the weight. A room in the center helps support the load of the roof. As an added bonus, they moved their longtime home brew operation into the new space and got it out of the house.

The garage is connected to the house via a main floor breezeway and a second story deck. An upstairs door offers the only way to access the green roof. Near the plants is a beehive decorated by local artist Jamie Anderson.

Nestled in the prairie is a sauna that’s been a great way to pull the neighborhood together in the winter months.

Green roof part of system of rain gardens and more

When the house needed a new roof eight years ago, Steffanie and Matt opted for a “cool roof.” The steel roof reflects sunlight and heat away from the building, reducing roof temperatures by 50–60°F over a typical shingle roof and helps the house stay cooler inside. The material is also a lifetime product.

“Water quality and stormwater management are really big values for us,” observed Musich. She started Friends of Lake Nokomis, and has served on the Minneapolis Parks and Recreation Board since 2014.

Given their proximity to Lake Nokomis, Musich wanted to replace an impermeable surface with one that would hold water in place and not flood the city’s stormwater system. “Part of what we’re trying to do is keep stormwater on our property for a longer period of time to reduce the volume of water the city infrastructure needs to manage during a storm event,” she explained.

Their green roof can hold a one-inch rainfall. More than that runs off the backside where they’ve done some regrading. They added a raingarden for Steffanie’s birthday last year that holds more water and keeps it from flowing immediately into the street. They plan to add another in the front in an effort to hold as much water as they can on site.

Over the years, they had also overseeded the backyard grass in favor of plants (such as clover) that help capture water and provide habitat for pollinators. They mow at 4 inches to allow for a deeper root system, which in turns means the plants are able to take more water into the ground than if the lawn was mowed shorter – a tip she learned through her master gardener training.

The best practices guidelines have been to hold a one-inch rainfall, although Musich foresees that may change as the state has been experiencing more and more high rainfall events. “One inch was unusual and on the high end, but now we’re seeing 2-3-4-6-inch rainfall events,” she said.

Musich pointed out it’s important to keep raingardens 10 feet from a building foundation to avoid basement flooding. Using a French drain between homes helps the water move and protects both homes.

Due to the way their home sits on their corner lot, their backyard is essentially their neighbor’s front yard. The new garage and green roof helped them carve out a private space.

“Plus we’re up in the canopy,” said Musich. “We get to see the birds and the squirrels in their element.”

‘Cathartic to care for natural space’

Initially, they planted 24 plugs with six different sedges, forbes, and grasses that were overseeded with a mix of annuals and perennials. Not everything was native.

White asters, white yarrow, black-eyes susan, mountain mint, purple coneflower, bachelor buttons, baby’s breath, columbine and more grow on the roof. The rooftop prairie starts blooming in April and continues through fall.

“The first thing that starts to bloom is the baby’s breath, which is self seeding. We’ll get a field of white which is beautiful at night,” said Musich. The first year, many poppies bloomed but they haven’t seen any since, and the wild indigo bloomed just the first two years. Meanwhile, the purple coneflower was elusive until the summer of 2019.

“It’s been very interesting to watch the evolution of the plants and the way they cluster and change,” said Musich.

The maintenance of the roof each year is minimal. “I’ll come out here and weed a couple times a month,” remarked Musich. “If I’m having a particularly stressful week, I’ll be out here more frequently. It’s very cathartic to care for a natural space.”

Benefits of green roofs

>>CLEAN WATER

Ordinarily, rainwater picks up contaminants and heat as it rushes across roofing and other hard surfaces on its way to lakes and rivers. Green roofs hold onto much of the rain, reducing the runoff that would otherwise cause water pollution and decreasing the need for additional (and expensive) stormwater treatment infrastructure.

>>LONGER-LASTING ROOFS

Because the waterproofing membrane is underneath the other layers of the green roof, it is protected from factors that can cause roofs to fail: extreme heat, UV radiation, and thermal swings. In general, green roofs last longer than conventional roofs, reducing both consumption and waste.

>>COOLER BUILDINGS AND CITIES

The plants on a green roof shade the building, and further cool it through the natural process of evapotranspiration. If enough roofs in a city are greened, they can combat the urban heat island and help mitigate the effects of global warming.

>>HABITAT CREATION

Green roofs create green spaces in the built environment that birds and beneficial insects can use as habitat. Green roofs also beautify cities, creating better habitat for humans as well.

>>CLEAN AIR

Green roofs improve air quality by taking up carbon dioxide and releasing oxygen, and by filtering airborne particulates.

~ Information from mngreenroofs.org