Every day, it seems, a new building appears in our skyline, whether in Iowa City’s downtown or Riverfront Crossings districts, Coralville’s Iowa River Landing, or in Tiffin or North Liberty. Sometimes the new building is LEED certified — Leadership in Energy and Environmental Design, the rating system used by the U.S. Green Building Council to measure a building’s sustainability and resource-efficiency. A few are even beautiful. But almost all of them have dead, black tar and asphalt roofs. Empty, heat-sink roofs. Wasted space.
Imagine seeing a magnolia tree in full bloom on top of an apartment building or prairie grass swaying in the breeze out your bedroom window. Imagine tending a vegetable garden on the roof of a school or strolling through a meadow on the roof of a hotel.
Despite our county’s recent environmental strides — e.g., Iowa City Council’s endorsing federal carbon fee-and-dividend legislation and mandating that multifamily units provide recycling — only a handful of buildings in our area have green roofs.
Green or “living” roofs — those partially or completely covered with soil and vegetation over a waterproof membrane — provide multiple benefits to individuals and communities. By absorbing rainwater, they reduce erosion, prevent flooding, and filter pollutants. They prolong roofing membranes by protecting them from ultraviolet rays. They conserve energy and lower air-conditioning costs by absorbing and reflecting heat. They reduce noise and air pollution, provide wildlife habitat and sequester carbon dioxide. Plus, research continues to show that visual and physical access to nature improves our health. (In one notable study, hospital patients with views of green space recovered faster.)
Green roofs can function as parks, urban farms, playgrounds, outdoor classrooms and peaceful retreats, even in winter. They can be public or private. They can be installed on most roofs (up to a 45-degree pitch), at various levels of cost, access, and maintenance — from shallow, lightweight, perennial grass plantings requiring little to no maintenance to deeper beds with trees and shrubs. According to the Environmental Protection Agency, simple green roofs cost about $10 per square foot to install and provide a 220 to 247 percent return on investment.
Given that green roofs improve our vistas, our air, our water, our soil, our moods, our health and our roofs; provide food; reduce community resistance to infill; create jobs; increase buildings’ marketability; pay for themselves; and, I would argue, make an area significantly more attractive to young professionals — why don’t we have more of them?
Two reasons, as I see it: lack of understanding and funding.
The U.S. as a whole lags behind the rest of the world in supporting green roofs. Germany has encouraged the industry since the 1970s via incentives and requirements at multiple levels of government, resulting in 10 million square feet of new green roofs every year. The U.S. installs 7 million.
That said, Chicago, Seattle and Washington, D.C., have robust green-roof industries, thanks to green infrastructure mandates, and San Francisco and Denver recently approved initiatives requiring all new and existing buildings meeting certain thresholds to incorporate green roofs.
I urge every jurisdiction in Iowa to develop green roof policies for all new developments. Cities and counties could also advocate for green-roof tax incentives at the state level, plus more funding for cities’ Stormwater Best Management Practices Grants, which financially assist residents who install stormwater features, including green roofs, on their properties. (Coralville, Iowa City and North Liberty currently provide these grants.)
If you’re a homeowner interested in installing a green roof on an existing building, first contact a structural engineer (most architectural firms have one on staff) to ensure that your roof can withstand the weight. While you can do the installation yourself, I recommend finding a certified contractor like West Branch Roofing, T&K Roofing or Country Landscapes, which work with Roof Top Sedums in Davenport. Visit jcgreenroofs.wordpress.com for a list of local financial resources and certified installers.
In this era of climate change, only cities that invest in green infrastructure will thrive. Iowa has embraced renewable energy. Now let’s take the next step and green up our rooftops.
Jenna Hammerich / Iowa City Press-Citizen