Rooftop dreams

Over the past 10 years, Tim Elam has converted his driveway into an idyllic space of meandering brick paths, shade-loving plants, relaxing sitting areas, garden sheds and a “cabin” retreat, with nearly everything built from reclaimed materials. His next project: turning his roof green. And by “green,” he means “alive.”

A green roof is basically a roof covered in vegetation, rather than shingles, tile or what the industry calls bare membrane.

“There’re so many dead traditional roofs—millions and millions of acres of roofs with no redeeming qualities,” said Elam during a recent Sierra Green Building Association greenUP! mixer. He was standing beside a prototype of the green roof water harvesting system he developed. It features a layer of sedum growing in about four inches of soil and gripping an open-weave mat, through which water runs and empties out through a hidden gutter. From there, it’s collected in a cistern. That water could be rerouted through the roof or used as graywater for other plants on the ground. Elam said wild grasses, succulents, sedum, strawberries or nearly any shallow-rooted plant can be grown on a green roof.

Why would anyone do such a thing? The benefits of green roofs include lower heating and cooling costs and controlling stormwater runoff. They’re nearly noncombustible depending on the plants chosen, they’re estimated to double the lifespan of the roof membrane on which they’re built, and they can add about six to 16 LEED points to your building, if you’re into that.

There are drawbacks, too. They require a bit more maintenance—like any garden, except weeded a few feet in the air. And installing one may need to involve a horticulturist, architect and structural engineer. At $15-$25 per square foot, they’re also more expensive than conventional roofs.

Green roofs are popular in places like the Pacific Northwest, a region of mild temperatures and lots of rain. But what about areas that receive high winds and harsh winters, such as Northern Nevada? Paul Laudenschlager, CEO of Alpen Engineering, said he worked on a living roof at Lake Tahoe’s Homewood Mountain Resort, and it’s survived two winters. Examples of green roofs stretch from Seattle to Chicago to Boston Harbor. In fact, the history of green roofs date back hundreds of years, from sod houses in Scandinavia to Vikingsholm in Tahoe.

“It goes back to the Hanging Gardens of Babylon, which likely leaked because they didn’t have the technology we do today,” said Elam. He’s talking about waterproofing membranes, which are also part of conventional roofs and help prevent leaks. And specially engineered soils reduce the weight load imposed on the roof’s structure. The weight is now comparable to putting Spanish tile on a roof, said Elam.

Though he’s trademarked the name GoGreenRoof water harvesting system, Elam doesn’t yet have a company, clients or even a set price for the system. He describes himself as just a guy with a product and a desire to see plants take over the rooftops of Northern Nevada and beyond. Everywhere he looks he sees green roof potential—on kiosks, on garden sheds, on high profile roofs in Reno.

“Fleischmann Planetarium is crying out to be a green roof,” said Elam. “It’d be killer.”