Green-Buildings.com sat down with Amy Norquist, founder and President of Greensulate to get some answers on return on investment, building benefits and why commercial building owners should consider a Greensulate green roof:

Green-Buildings.com: What is a green roof?
Amy: Simply put, a green roof is a living and growing system placed on top of a building's roof. A green roof mimics nature and is more similar to a yard than to a roof top terrace garden. There are several protective layers that separate the growing medium (soil) and plants from the roof's membrane, these layers include (from membrane up): a root barrier, moisture retention, drainage layer, filter fabric. These essential layers ensure that there will be NO chance of protrusion into the membrane by the roots of the plants. The plants used most often are called sedum, a high altitude plant that can withstand harsh weather conditions and does not need to be watered as much as most other vegetation. The growing medium is a manufactured “soil” with a mix of organic and inorganic materials making it extremely durable while able to absorb a lot of moisture A green roof is a beautiful transformation to an otherwise unsightly roof and helps save money, energy, and the environment.

How does a green roof help make a building more energy efficient? How do they work?
Put your hand on asphalt on a hot day then put your hand on a plant in the middle of a hot day. The difference that you feel is the basis of how green roofs make a building more energy efficient. A rooftop garden is an incredibly efficient layer of insulation.

During peak summer temperatures, rooftops can reach an excess of 190 degree Fahrenheit. During this same time, a green roof will maintain a constant temperature of closer to 80 degrees! It’s simple, when a roof is extremely hot, the heat permeates the entire building creating greater need for AC. This especially true in urban areas, where the increased percentage of concrete and tar roofs makes the overall city temperature greater by more than 10 degrees. Thus, when a building’s roof temperature is cut in half, the overall building (and city’s) energy needs decrease. In winter months the green roof acts as an insulating layer, holding more heat in than a standard roof.

How much does a Greensulate green roof cost?
Price varies from project to project depending on plant choice, accessibility to the roof and design choices. The average extensive green roof (less than 6 inches of growing medium) will cost between $15-$35 per square foot.

How long does a Greensulate roof take to install? Is there a long lead time?
Once the roof is fully waterproofed and a structural engineer has approved the weight load capacity for the roof (NOTE: these two steps must be done before any green roof installation occurs), an installation can take as little as one day for small projects. The lead time for a green roof is generally around 3-4 months (including the engineering and roofing). This can be made shorter under ideal circumstances.

What makes Greensulate different than other green roof and/or wall products? Why should a building owner choose Greensulate over another green roof provider?
Greensulate is an extremely friendly and professional expert on green roofs and green walls and we take pride in making sure every project lives up to our client’s expectations. We are a one-stop-shop green roof company that handles everything from getting the roof ready for the installation, designing the green roof, installing the green roof and also maintaining the system once completed. As part of our service, we partner with an extremely competent roofing contractor to ensure the roof is waterproofed correctly and receives all available warranty protection.

We also have the ability to choose any green roof system available. Many other companies are bound to their specific product. Greensulate finds the best system for the best price that fits with the client’s budgetary needs.

Where are Greensulate products available?
Our offices are located in New York City, Shelter Island and San Francisco. We are able to do installations anywhere across the country.

In terms of payback/ROI, what are the ideal installation conditions for a green roof?
Green roofs can double (and there are examples of it even tripling) the life of a roof by reducing the expansion and contraction of the membrane. It also protects from foreign objects and from UV degradation. Energy saving benefits are most significant in a single or two story unit or in buildings that are touching (such as commonly found in NYC brownstones and apartments).

Could you provide a return on investment (ROI) calculation for a Greensulate green roof installation?
With every project we provide the client with the estimated ROI and environmental benefits (such as tons of carbon and particulate matter absorbed)

Which Greensulate installation are you most proud of? Why?
We recently completed a stunning green roof on a six-story penthouse in Tribeca where we were able to incorporate a wide variety of native plants and sedum of varying sizes, shapes and colors. The space is viewable from all rooms of the apartment. It truly was amazing to see how much the penthouse was transformed after the green roof was installed. Butterflies and bees found the newly planted vegetation almost immediately. This installation is the epitome of how dramatically green roofs can enhance a building’s aesthetic, not to mention greatly increase its resale value. We also installed rain barrels to capture the water from the roof that the client will use to irrigate the rooftop.