Happy 4th of July everyone! We hope you all had fun kicking back for a mid-week holiday to celebrate the birth of these great United States of America.
If you reside in an urban environment, one of the best spots to chill out and watch 4th of July fireworks is a rooftop. Whether a rooftop bar or restaurant, rooftop amenity space that your office building kept open for the holiday, or a residential rooftop deck of any kind – roofs offer a view above the hustle and bustle of city life and a chance to see the show.
Rooftops of all kinds are on the rise, but green roofing in particular– those on terraces, roof decks, setbacks, or any other flat building surface – is a market quickly expanding.
In an Energy Manager Today article by Carl Weinschenk, March 2016, Erik Vickstrom, the lead consultant for Acceleration Advisors and author of “Energy Retrofits for Commercial and Public Buildings: Global Markets,” found that, in 2015 the value of the North American green roof market was $130.1 million. It was $946.4 million in Asia Pacific (covering Japan, India, China, South Korea and Australia) and $3.6 billion in the U.K, Germany – the world leader in green roofs — and France. The growth will be significant. A compound annual growth rate (CAGR) through 2020 of 34.9 percent will bring the value of the North American market to $582.1 million. The CAGR in Asia Pacific will be 25.4 percent to bring the market value of $2.9 billion. The three European nations will have a CAGR of 16 percent to reach $7.5 billion. The United States is growing faster than Canada.”
The benefits of green roofing are plentiful – they can provide stormwater management, energy savings, increased biodiversity and habitat, reduce urban heat islands, extend roof longevity, and add beauty (and therefore, value) to an otherwise blank aesthetic, according to GSA’s green roof report. We encourage you to check out the GSA green roof report – while it’s dated to May 2011, it continues to be a valuable resource for implementing green roofs.
For additional resources, check out the following:
>Green Roof Performance Data report by the American Society of Landscape Architects
>Green Building Alliance’s green roofing resources.
>Green Roofs for Healthy Cities. This organization provides a Green Roof Energy Calculator tool, and also conducts an annual survey of its “corporate members to collect data on the growth and composition of the green roof industry across North America.”
With regard to cost-benefit analyses, the GSA report asserts that:
>”GSA’s green roof report estimated that green roofs on commercial and public buildings provide a payback, based on 50 year average annual savings, of about 6.2 years nationally, internal rate of return of 5.2%, and an ROI of 224%, based on a net present value of $2.7/square foot.”
>”Primary green roof costs are related to installation and maintenance.”
>”Primary economic benefits of installing green roofs are lower energy costs, less frequent roof replacement due to greater durability, reduced stormwater management costs, and creation of job opportunities.”
To learn more about the current affairs of green roofing, we spoke to Andrew Franz, founder and head of the New York City based architecture and design studio, Andrew Franz Architect. We were interested in speaking with Mr. Franz because of his work in New England; he asserts that in Manhattan alone, there are 40,000 total acres of rooftops still unplanted. According to the Nature Conservancy, at least 1,200 buildings in New York City alone now have green roofs, totaling about 60 acres.
OI: You told us that you also spoke about a NYC Council bill passed in April, that will require “all new and significantly renovated residential and commercial buildings in the city to top roofs with either plants, solar panels, mini wind turbines – or a combination of all three.” Can you tell us a little bit more about how policy is shaping the green roofing market, and what we can expect in the years to come?
AF: New York City is not the leader in green roofing or in policy measures like this – cities like Vancouver, Singapore, and stateside, cities out west are really leading the market. But, New England is a really harsh climate to work in; it battles a lot of elements that many other regions don’t. Its taller buildings provide extra challenges; the taller the building, the higher the wind load, and more limited types of vegetation you can use. In New York right now probably less than 10% of roofs are green roofs. Taller structures will opt for doing wind turbines, but green roofs are ideal for the 6-8-10 story buildings. The bill passed in April is very ambitious.
OI: Where is the industry headed with regard to innovation?
AF: Innovation is really happening in ease of installation and in knowledge. First, there are many more providers of lightweight materials and already prepared trays. The solutions are more modular, so you can easily build and adjust them. We also have a far more educated base of installers that we’re now working with, so projects are able to run much faster and more smoothly.”
OI: What are commercial building and workplace clients looking for in green roofing?
AF: There are two things. First, commercial clients are calling for roofs to be an amenity marketing tool. They want to be able to tell their tenants or employees, “We are a green building, we care about the environment and space around us, and we know that’s important to you.” Second is a more authentic point in that people genuinely want to be outside. Tenants want to have an outdoor space to go to, for both social and health reasons.
OI: How educated are clients about green roofing right now?
AF: While clients are very excited and educated about the benefits green roofs provide to both the environment and us as humans, they’re still not educated about roof membrane structural issues that can impact a green roof project, and the general costs associated with a green roof project.
OI: Urban life, where noise pollution is greatest, is growing. We checked out studies on noise and sound insulation and found some interesting elementary research from livingroofs.org. Do you believe in the ability of green roofing to help reduce noise pollution?
AF: “Measuring how green roofs could help reduce noise pollution in urban areas is a fascinating topic to explore. It seems to me that while the horizontal roof space above could have an impact, the more impactful move would be to activate the sides of buildings. It’s a very interesting space to look into. There’s no reason not to include green roofing in as many projects as you can. There are so few drawbacks, and so many benefits.”
An Architects’ Guidance on Green Roofing
Andrew Franz offers his top of mind on the current green roofing landscape
>Make green roofs an architectural experience.
“We encourage clients to open up floor plans and provide view corridors to planted roofs and garden terraces. Studies in biophilia have long established what we all knew instinctively, that extending views to the exterior, connecting people to nature adds enjoyment (and efficiency) year ‘round to living, working and playing. On one roof, we created a sunken courtyard with a large retractable glass roof to connect entertainment areas to the new green roof and deck above, both visually and physically. This interior court brings views, natural light, better air circulation, and accessible outdoor space into the primary living areas.”
“Planted roofs and terraces must be evaluated in terms of structural capacity, roofing materials, drainage, irrigation needs and overall maintenance. For example, durable and modern liquid membranes or tough singe-ply roof systems are ideal for a green roof installation, says Franz. Watering may be essential for some ‘intensive’ decorative gardens and turf roofscapes, while ‘extensive’ roofs planted mostly with sedums and drought-tolerant species will not need irrigation and will actually manage storm water which is one of the reasons why many municipalities now have programs to encourage or even mandate green roofs. The controlled run off saves the municipalities money and also protects the adjacent rivers or waterways. Green roofs are as good for the environment as they are for homo sapiens.
>Protecting the roof end adds even greater R value.
“Except for those roofs planted with sedums, roof gardens of most kinds need water, and protecting the house or building below is critical. Adding a few inches of rigid insulation, topped by a properly installed drainage membrane, can support the lightweight soils for almost any type of plantings while protecting the roof membrane and adding greater R value than the soil alone. Every 1” of rigid insulation significantly increases the R value of the roof.”
“In fact, we are often asked to design green roofs because of these cost saving and environmental benefits. With the new insulation below and the lightweight soil above, energy demanded for heating or cooling the spaces below can be dramatically reduced, saving money on utility bills. Plus, on a large scale they reduce the urban heat island effect by absorbing light that would otherwise become heat energy.”
>Compare initial costs vs. long-term costs for green roofs.
“Based on data from thousands of green roofs from San Diego to Boston, Franz estimates the total costs at about $20-30 per square foot for ‘extensive’ roof installation in major cities. He cautions, however, that budgets can vary greatly based on building type, roof surface, elevators, and the like – so he encourages all of his clients to request early budgetary estimates. Sometimes craning materials up can provide substantial savings. However, over the long term the investment pays off, extending the life of the existing roof and providing substantial energy savings, as mentioned above.”