This Web exclusive to FacilityBlog comes from Kelly F. Duke, vice president for pre-construction services at Calabasas, CA-based ValleyCrest Landscape Development.
Green roofs are easy and effective ways to beautify facilities while enhancing a building’s energy efficiency. These types of structures include vertical landscapes, green walls and roof-top gardens; they are currently playing a vital role in the development of LEED-certified buildings across the country.
Architects and building owners are increasingly understanding and embracing the value of sustainability in their developments, and today, roof-top level gardens are being incorporated into nearly every type of commercial structure including high-rise offices, hotels and resorts, residential, mixed-use, and retail properties.
There are really three types of roof-top gardens:
1. Intensive: An accessible, park-like roof garden with conventional trees and plants requiring irrigation, feeding and maintenance.
2. Extensive: A traditional blanket of green material, such as sedum, or select ornamental grasses or ground covers, not accessible to the general public, requiring little maintenance.
3. Semi-intensive: A combination of both types.
Some of the direct benefits of green roofs include:
- Ability to moderate roof-top storm water runoff
- Supplement a building’s insulation, reducing heating and cooling costs
- Offer new outdoor amenity space
- Moderate daily solar heat gain to reduce urban heat island effect
- Improve air and water quality by filtering and reducing pollutants
- Create aesthetic value
- Increase wildlife habitats and biodiversity in urban settings
- Lower the temperature of the water that is eventually returned to the watershed
Here’s a look at three green roofs and roof gardens recently installed by ValleyCrest Landscape Development around the nation:
Eaton Vance Green Roof, Boston, MA
Eaton Vance Corporation, a Boston-based investment firm, relocated its headquarters to the Financial District in downtown Boston. This 310,000 square-foot office building underwent a full retrofit including the addition of an outdoor entertaining space and landscaped roof deck. Included in this renovation was an intensive roof garden that affords employees and their visitor’s views of Boston Harbor and the newly constructed Rose F. Kennedy Greenway. The 13th floor green roof includes square and round pre-cast concrete planters filled with Skyline Honey Locust trees as well as 200 perennials and 350-square-foot blanket of sedum material.
Optima Biltmore Towers, Phoenix, AZ
Optima Biltmore Towers helped transform the Phoenix skyline with its environmentally friendly design. A green roof caps the towers where a trellised sky bridge links condominiums to a recreation area offering residents a natural view. The property integrates solar systems that compliment an environmentally sensitive green roof and retreat. The landscape and irrigation system include a pool and spa as well as arbors for shade. Nearly 300 boxed trees and 2,000 shrubs were planted on the 17th floor.
The Prologis Corporation, Denver, CO
Prologis, one of the largest global providers of warehouse and distribution space, expanded and added a roof-top garden bridge above an atrium that connects two buildings at a Denver-area campus. Plants and trees native to the region were planted in a 16″ deep tray, while a special drip irrigation system runs from inside the building and distributes water directly to the root of the plants. Pavers made from recycled concrete onsite line the walkways for pedestrians. The building is now registered as LEED Silver and is awaiting certification.
These green solutions are prime examples of how green roofs can help bring nature closer to urban settings, improve insulation and air quality, and work to deliver both economic and social benefits to their communities.