Green Roofs - Living Architecture Monitor - Summer 2011 - (Page 35)

ON SPEC SEVEN-YEAR PITCH LESSONS LEARNED FROM MY GREEN-ROOF GARAGE By Lois Vitt Sale eave to eave. The roof is about 525-square-feet. The mantra in the early days of green roofs was minimal maintenance, minimal watering. The landscape would sustain itself. This leads me to lesson three: with a sloped roof, I now recommend installing drip-irrigation on the high side of the slope. The lack of irrigation was not a disaster, but more species of plants might have remained in place if they had access to water. In seven years, I've had no leaks, no failures, and have learned to stay off the roof. But each year, at least once or twice I've had the original landscape contractor, Intrinsic, come back to the roof to do a spring clean-up and fertilize the roof. Lesson four, therefore, is that there is no such thing as a maintenance-free green roof. Seven years later and I still miss those early cheddar pinks and daisies. I'm not sure if this means I have not yet fully embraced the experience of being the owner of a green roof, or whether it is just the seven-year itch. Either way, it has been both a challenging and fascinating journey. T he intersection of building and nature on my green roof has challenged my architectural sensibilities. "What?" you may ask. "Don't you like your green roof?" Yes, of course, I like my green roof, but as an architect, I'm used to things staying put! The lines of a building, the way the light strikes a detail at a certain time of day. The way a color changes depending on its source of illumination: these are all changes that I expect in the visual experience of a realized design. But a living roof goes way beyond those fleeting changes. Seven years ago, in the course of building a second-storey addition to my home, I added a green roof to my one-storey attached garage. With a slope in excess of 30 percent it was, at the time, the steepest green roof in the Chicagoland area. Its depth varies from two to five inches of growing media over a Styrofoam layer that looks like an over-sized egg crate and is designed specifically for sloped applications (Zinco Floratech). Access to the roof is either from ladders below or through a window in my master bedroom. But, with its fairly steep roof and thin layer of growing media, lesson one was to learn to walk on it as little as possible to keep the system from migrating down-slope. Originally the roof was planted with dianthus that bloomed hot pink early in June, Heuchra, Allium, trailing strawberries, thyme, yarrow, bluegrass, several varieties of Sedum and more. Each year, a different variety would reign supreme and the plants moved themselves to where they would receive the nutrients, micro-climate and rainfall they needed. I have had the year of the cheddar pinks, the year of the daisy (seeded themselves), the year of Sedum blooming brilliant gold (Weinstepner Gold) and this year was the year of the Allium with its round purple blooms. What has happened over time is that certain varieties have outcompeted others. The Dianthus (cheddar pinks) have all but disappeared and the Sedum and Allium have ascended to a position of dominance on the rooftop. Therein lay lesson two: if your building a green roof, you need to build in the expectation for change. (And as I said, this doesn't come natural to an architect.) There was no irrigation installed on the roof. During its first, full growing season, there was a drought. Seriously, that year the amount of precipitation was 30 percent below normal or, put another way, 12-inches of rain that never fell. I placed an oscillating sprinkler on the ridge that was able to water the roof from Lois Vitt Sale, AIA, LEED Faculty is senior vice president and chief sustainability officer for Wight & Company based in Darien, Illinois. LIVING ARCHITECTURE MONITOR SUMMER 2011 35

Table of Contents for the Digital Edition of Green Roofs - Living Architecture Monitor - Summer 2011

Green Roofs - Living Architecture Monitor - Summer 2011
Water Worries
Cities Re-Imagined
Design Strategies for Wild Bees
Special Section: Cities Alive 2011 Conference Guide
Thin Flats
Sky Island at the Visionaire
Welcome New Members
New Corporate Members
Professional Calendar
Seven-Year Pitch

Green Roofs - Living Architecture Monitor - Summer 2011