sustainable building rooftop activations
How can rooftop activations contribute to a sustainable green building plan? Biofilico healthy building consultants review some of the leading example from around the world covering the USA, UK, Thailand. We look at the role of apiaries, rooftop farms and gardens, solar panels and more.how can rooftop activations contribute to a sustainable green building plan? From apiaries to gardens, solar panels and more, here are some inspiring examples
CookFox offices Bee hive apiary, NYC, usa - sustainable building rooftop apiary
CookFox is one of the world's leading sustainable architecture and biophilic design specialists working at scale. Based out of New York City, they are on the cutting edge of environmentally responsible architecture and aim to design healthier urban landscapes.
Starting with their own rooftops, they have increasingly begun to introduce apiaries - bee hives - where conditions and space allow.
Bees are an example of what’s referred to as a ‘keystone species’ as they are massive pollinators providing an essential cog in local ecosystems, even in dense urban environments.
By dispersing pollen for plant reproduction they help to maintain biodiversity and counteract the risk of habitat fragmentation - as agriculture and urban planning tend towards the destruction of species rather than their protection.
As a way to lead by example, CookFox houses two large hives on the terrace of their corporate office. They also introduce apiaries to their development locations such as the Solaire residential apartment building located in New York City.
La Pista500 rooftop garden, turin, italy - example of green building design
Fiat's former car factory located in Turin, Italy was recently crowned with a new rooftop garden designed by Camerana&Partners, completing tis transition from a historic car factory to a hub for the local community. Originally this was where Fiat cars would be tested on the rooftop track before being sent out to their customers.
Today, this 42-acre rooftop has a very different purpose as much of the asphalt track has been sowed with a meadow of 40 different local plant species. A smaller, less prominent car track still exists however, albeit for test driving electric cars only.
The space is occasionally used as an art installation space or venue for yoga classes, a perfect example of green buildings giving back to the local community through culture and wellness.
Thammasat University Urban Rooftop Farm (TURF), Thailand
Thammasat University in Thailand implemented a rooftop green building solution to improve their climate resiliency in the face of rising impacts of climate change. As urban sprawl consumes territory that previously played an active role in a complex local ecosystem, they are no longer able to absorb stormwater runoff for example.
This example (shown above) is the largest urban rooftop farm in Asia, with over 22,000 m2 of modern landscape architecture brilliantly combined with traditional agricultural knowledge. Combined, it becomes a green roof with elements of urban farming, solar panels for green energy and plenty of green public space for nature connection and an opportunity for biophilia.
Inspired by traditional rice terraces, we see a cascade of different levels to the rooftop that form a detention lawn to slow down, absorb and store rainwater while simultaneously putting it to good use as irrigation for plants that produce food.
Stormwater runoff is filtered through each layer of soil (removing harmful pollutants) and later saved up in four retention ponds, for rooftop irrigation and future use, meaning nothing goes to waste. This makes it up to 20 times more efficient than a normal concrete rooftop whilst also helping to mitigate the urban heat island effect. Finally,. solar energy is used to pump the irrigation system and additionally contribute to the building’s electricity needs.
The self-sufficient structure acts as a space for the public to enjoy nature, a food source, a water management system, an energy source, and an outdoor classroom.
Fifth & Tillery, Austin Texas - green rooftop architecture
This example by Gensler Architecture of using photovoltaic panels as a functional rooftop structure shows where green architecture can go in the future.
Owned by the CIM group, this three-story mass timber office development located on an ex-industrial estate required additional shade for the plaza below, by introducing a canopy of photovoltaic panels, the benefits were therefore two-fold - integrating a source of renewable energy and improving occupant wellbeing.
A tree-lined central courtyard "rain garden" is intended to resemble the "native ravine microhabitats of Central Texas" while louvres with integrated fans were positioned around the courtyard to improve airflow and ventilation in the outdoor spaces. Effectively, this begins to ‘turn the traditional office building inside out’.
The solar panels on stilts are a fundamental piece of the arrival experience above the entrance. This canopy combined with the additional panels on the building's rooftop can provide up to 600 kilowatt-hours (kW) of power for the sustainable building.
Culpeper restaurant, London - green rooftop garden
Responding to the largely under-used rooftop spaces that populate the centre of London’s dense urban landscape, The Culpeper pub team decided to convert their space into one for food production as a way to contribute back to the local community.
Far from trying to replace the work of farmers in the rural areas around the capital, the 500 sq ft space is more about improving the quality of urban life, just a touch. Rooftop produce may appear in the form of a garnish, something in a pickle or as part of a dish, rather than dominating the ingredient list.
Typically it is smaller, younger plants such as herbs, salad leaves and vegetables growing in mushroom compost reused from mushroom farms mixed with horse manure and top soil. Kitchen leftovers are combined with soil in a wormary to keep the soil fertility alive.
Although the produce is not certified organic, the growing methodology follows organic standards, with no chemicals on the soil or plants.
This is an example of how a hotel, restaurant or pub can use a garden area to reduce organic waste, produce on-site ingredients (with a little extra effort) and provide guests with a direct connection to nature - biophilia.
Sustainable Rooftop: A Key Element in Green Healthy Building Design — Biofilico Wellness Interiors
Biofilico healthy building consultants explain how the implementation of green roofs within a sustainable building strategy can provide benefits such as: a reduction of Urban Heat Islands; increased energy efficiency; improved rainwater management; improved biodiversity; the provision of amenity spaces
Why Green & Healthy building Rooftops?
Roofs can take up to 15-35% of the total land area of a city, making them a vital surface in urban settings (“Urban”). This often underutilized area of a building envelope can provide smart, healthy, and environmentally friendly design options that are increasingly being executed across cities.
The implementation of green roofs within a sustainable building strategy, for example, can provide benefits such as:
a reduction of Urban Heat Islands
increased energy efficiency
improved rainwater management
improved biodiversity
the provision of amenity spaces
Compared to conventional roofs, green roofs have lower burning heat load and lower temperatures. They also include materials not found on conventional roofs, which contribute to their environmental benefits. Additionally, the installation of green roofs requires experienced roofing contractors to ensure proper setup and maintenance.
Green roofs are the most holistic and multifaceted design strategy for these surfaces, but other considerations such as cool roofs, the incorporation of rooftop gyms or exercise areas, and solar panels are a few examples of smart rooftop design that contribute to a healthy building or sustainable building strategy.
Sustainable building rooftops Reduce the Urban Heat Island Effect
One of the most important influences that rooftops can have is a reduction of Urban Heat Islands (UHI). This phenomenon describes the prevalence of higher temperatures that arise in dense, urban regions, due to the presence of man-made surfaces with higher heat retaining properties than those in natural environments.
Out of the entire building envelope, roofs are subject to the highest amount of solar irradiance, making their albedo properties the most important to curb the effects of UHI (Costanzo).
With the rise of temperatures across the globe comes the rise of heat related deaths. Increased respiratory disease, heat stress, reduced productivity, discomfort, and mental health challenges can all also occur due to increased warming (Swain).
With UHI compounded with the rising temperatures, the physical health and wellness of those residing in cities becomes more dire—making it an essential problem to address.
The most common strategies to reduce UHI on roofs is to implement cool or green roof strategies. Cool roofs use highly reflective coating such as white paint to reduce heat absorption, while green roofs implement plants and other vegetation, which acts as insulation and a cooling mechanism for the building and surrounding microclimate.
Additionally, green roofs and cool roofs can reduce the energy demand for air conditioning by keeping the interior temperature cooler and lowering energy bills.
Increase Energy Efficiency via green roofs
The implementation of smart roof design has the potential to greatly increase building energy efficiency. For one, green roofs can reduce building cooling loads and therefore increase HVAC efficiency. Also, Solar panels can be implemented on roofs to grow renewable energy use.
When used in tandem, green roofs and solar panels can be implemented on the same roof and provide dual benefits. Reducing energy consumption through green roofs can also help in reducing greenhouse gas emissions.
Generally, roofs are dark, heat absorbing surfaces that have the potential to raise building temperatures and increase cooling demands. Plants and greenery naturally reduce the temperature of roofs and add an insulation layer, diminishing the amount of hot and cold air affecting the building’s temperature, further regulating it.
In addition, the cooler microclimate created by rooftop greenery can increase the efficiency of rooftop HVAC systems (“Green Roof Benefits”).
In addition, solar panels can be placed on rooftops to act as a renewable energy source for a building. Although usually thought of separately, if a green roof and solar panels are used together, known as a biosolar roof, the benefits increase.
Like rooftop HVAC systems, solar panels work more efficiently in cooler climates, making the combination of vegetative cooling and solar panel energy creation a beneficial, symbiotic relationship (“Green Roofs-Solar”).
Improve Rainwater Management on green rooftops
Rainwater management and collection is a commonly mentioned concept in many building certification and rating systems, and can be improved through the implementation of green roofs. Impervious surfaces and hardscapes cause excess water runoff, which can disrupt natural hydrology and ecosystems, as well as contaminating water bodies with pollutants.
Green roofs reduce the amount of stormwater runoff and delay the time at which runoff occurs, resulting in decreased stress on sewer systems at peak flow periods. Pervious surfaces that allow for water absorption, capture, and reuse can be implemented through green roofs and through the incorporation of surfaces such as porous pavement or grid pavers.
Green roofs can capture the water as it falls, and filter out its pollutants naturally, reducing the burden on sewer systems and avoiding flooding, as well as preventing toxins from entering water bodies. It has been found that green roofs can hold 70-90% of the rain that falls on them in the summer, and 25-40% in the winter (“About”).
Once captured, this water can be redistributed throughout the building such as in irrigation, toilets, and other non-potable uses.
The use of green roofs and pervious landscaping can greatly impact rainwater management and reduce water demand within buildings.
One study done by researchers at Pennsylvania State University found that green roofs retain around 80% of fallen water, while traditional roofs captured closer to 24% of rainfall (“Green Roof Benefits”). However, when designing roofs for rainwater capture and reuse, it is essential that loads are calculated, and proper sealing of the building envelope is executed to avoid any leaks.
Improve Biodiversity with a green rooftop
Cities are barren compared to the natural world, and therefore provide fewer habitats for flora and fauna. Implementing green roofs within urban regions is a way to use often underutilized spaces to increase the presence and diversity of species within the built environment. Green roofs contribute to creating green space in urban areas, supporting biodiversity and improving the urban environment.
Increasing biodiversity in cities can not only improve the health of those ecosystems themselves, but also the systems that function around them–such as the hydrological or nutrient cycles. In addition, from a mental health standpoint, the visual presence and interaction with a diversity of species can be positive for human well-being (“About”).
Plants, especially native species promote the livelihood of birds, insects, and butterflies and restore the ecological cycles that are often disrupted in cities. In addition to providing an immediate habitat for animals, green pockets can provide places of respite for animals and provide more closely connected habitats for migrating birds and other species that would otherwise be fragmented by cities (“About”).
In addition to greenery, when solar panels are implemented as well on biosolar roofs, they can provide additional landscape diversity. The panels provide shade and protection, as well as a place for water runoff, creating a wetter side and a drier side. The implementation of PV can therefore cause a “habitat mosaic”, attracting a wider variety of flora and fauna and further increasing biodiversity (“Green Roofs-Solar”).
nike rooftop activation barcelona
Provide Amenity Spaces with a healthy building rooftop
In addition to the ecological benefits of green rooftops, they can also provide social and mental health benefits for building users. Strategies such as rooftop gyms and community gathering spaces can provide further benefits. Green walls can also contribute to urban greening by providing additional green infrastructure and improving air quality.
Outdoor exercise has been proven to have additional benefits when compared with traditional exercise, such as greater mood improvements, decreases in anxiety and increases in the desire to be active. Due to the mental and physical health benefits from both nature exposure and exercise, the combination of the two provides even greater gains (Loureiro).
Implementing exercise spaces and gyms on rooftops is an impactful way to improve the health and wellness of building users, while avoiding building footprint increases. Rooftop gardens can provide amenity spaces and enhance the sustainability of urban areas.
In addition, publicly accessible rooftops can provide places of respite and locations to gather as a community. Community gardens can be placed to encourage building users to spend time outside in nature, provide educational opportunities, improve nutrition and food awareness, and reduce the local community’s food footprint (“About”).
Finally, aesthetic roofs with various amenities can encourage occupants to utilize the space for events and social gatherings, further promoting community, connection to the outdoors, and overall wellness.
Sources
“About Green Roofs.” Green Roofs for Healthy Cities, https://greenroofs.org/about-green-roofs
Costanzo, V., et al. “Energy Savings in Buildings or UHI Mitigation? Comparison between Green Roofs and Cool Roofs.” Energy and Buildings, Elsevier, 12 May 2015, www.sciencedirect.com/science/article/pii/S0378778815003527.
“Green Roof Benefits.” National Parks Service, U.S. Department of the Interior, https://www.nps.gov/tps/sustainability/new-technology/green-roofs/benefits.htm.
“Green Roofs and Solar Power – Biosolar Roofs Are Smart Green Infrastructure.” Livingroofs, 29 Oct. 2019, https://livingroofs.org/green-roofs-solar-power/.
Loureiro, Ana, and Susana Veloso. “Green Exercise, Health and Well-Being.” ResearchGate, Springer, Aug. 2017, https://www.researchgate.net/publication/308099577_Green_Exercise_Health_and_Well-Being
Swain, Sunanda SwainSunanda. “Urban Heat Island Effect: Causes, Impacts and Mitigation.” Blogging Hub, 4 June 2019, www.cleantechloops.com/urban-heat- island-effect/.
“Urban Roofscapes: Using ‘Wasted’ Rooftop Real Estate to an Ecological Advantage.” Scientific American, Scientific American, 25 July 2008, https://www.scientificamerican.com/article/urban-roofscapes-ecofriendly-rooftops/.
Sustainable Urban Rooftops with UrbanStrong
In this episode of Green & Healthy Places podcast, we discuss trends in rooftop gardens in New York in the wake of Covid lockdowns, the wellbeing benefits of connecting with nature on a rooftop, as well as the economic and environmental benefits of a green roof from a range of different stakeholder perspectives - occupants, developers and city government. We look at green roofs and stormwater management, new legislation pushing for green and solar rooftops on new build projects in NY, the opportunities in rooftop food production.
Green Roofs for green buildings
Welcome to episode 041 of the Green & Healthy Places podcast in which we discuss wellbeing and sustainability in real estate and interiors. This week I'm back in Brooklyn, New York talking to the Principal of UrbanStrong Alan Burchell.
Alan trained as a mechanical engineer, with a background in HVAC and plumbing systems then slowly migrated across into renewable energy and eventually to vegetative rooftops so he has a very technical, hands-on take on the practicalities of urban greenery solutions.
Green Rooftop for wellbeing
We discuss trends in rooftop gardens in New York in the wake of Covid lockdowns, the wellbeing benefits of connecting with nature on a rooftop, as well as the economic and environmental benefits of a green roof from a range of different stakeholder perspectives - occupants, developers and city government.
We look at green roofs and stormwater management, new legislation pushing for green and solar rooftops on new build projects in NY, the opportunities in rooftop food production and green roofs in the context of the healthy buildings concept.
Vegetative Roof Benefits
Arguably my main takeaway from this convo is the interconnectedness of benefits once one brings nature back into the city via the rooftops, they deliver multiple functions at once, even if the building owner is not actually interested in half of them! It’s a valuable insight and Alan has a positive message to spread, so enjoy the episode and hit subscribe to receive next week’s download too.
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Conversation highlights
It doesn’t feel right that with we have so little opportunity to connect with nature here given the huge percentage of our lives we spend in dense urban centers.
Green roofs clean and cool the air, sequester carbon and provide rooftop habitats for birds, bees, bats, butterflies, and much more.
Farm-to-table is great but roof-to-table is even better
Green roofs perform multiple functions with societal, environmental, building operations, and mental health benefits, all simultaneously.
Building owners should be thinking of their rooftops as buckets instead of lids, because there's money falling out of the sky.
Solar panels lose operating efficiency when the ambient air around them gets too hot but Plants cool the air around them through through evapotranspiration so when you install solar panels directly on top of green roofing, the plants cool the air underneath the solar panels and help them to produce more electricity
GUEST / ALAN BURCHELL / PRINCIPAL, URBANSTRONG
HOST / MATT MORLEY / WELLBEING CHAMPION
FULL TRANSCRIPT FOLLOWS COURTESY OF OTTER.AI (excuse typos)
MM
Alan tell us about your background in sustainability and how you came to be the principal at UrbanStrong
AB
Sure thing. First of all, Matt, thanks for having me. It's a real honor to be on the show. So formally, I trained in undergrad as a mechanical engineer, and a lot of mechanical engineers who don't know what they want to do coming out of school University wind up getting sucked into working for consulting firms, specifically engineering consulting firms.
So I worked at a mechanical electrical consulting firm who did all kinds of work for different building types. And I specifically was designing HVAC systems, plumbing and piping and fire suppression systems for banks, condos, restaurants, you name it, that was a little bit dry. I was a little bit young, that was kind of living for the weekends. And I realized I needed a change. And I didn't know this term at the time. But what I was looking for was a career path with a vein of some sort of social responsibility going through it.
So I went back to school, I did a business degree and found the world of renewable energies. And within the world of renewable energies, wind energy was most appealing to me. It had the dynamic nature of wind turbines that appealed to the mechanical engineer in me, but then the renewable green energy component that appealed to the the outdoorsman and the environmentalist
I worked in that industry for a Spanish wind turbine manufacturer at their North American corporate headquarters just outside of Philadelphia.
Eventually, then, I wanted to get further entrenched in the world of sustainability. I started studying up on the space and I found the world of green vegetated rooftops and that really checked a lot of boxes for me because I'm a big city as much as I love the outdoors. I really like big cities, I've had the blessed opportunity to live in several around the world. Toronto, Barcelona, London, Shanghai, Philadelphia, now New York, and it never sat well with me the idea that in order to connect with nature, someone had to get out of the city, like go up to a cabin or cottage lake house go to the beach.
It doesn’t feel right that with we have so little opportunity to connect with nature here given the huge percentage of our lives we spend in dense urban centers.
I had a side interest in architecture, interior design, and every cubicle or office I've ever had has always been chock full of plants.
I realized that green roof systems are multifaceted in their benefits, and that they offer to building owners, people battling climate change, municipalities looking to mitigate issues that plague modern day dense urban centers… they checked all these boxes.
So I went into the world of green rooftops, I first naively thought, Great, I'll start my own Green Roof Company. And then I realized very quickly that there are already several people doing this design build firms in New York City doing exactly this. So I couldn't really go from never having heard of green roofs to being competitive in the New York City Market in a short span of time.
Instead, I decided to insert myself in the market in with the only tools that I had with me, other than enthusiasm for green roofs, and that was engineering system sales. And so from my previous career, I started basically offering third party, freelance business development or a really dirty word for it would be brokerage of green roof sale.
I would go out and beat the streets and look for clients and building owners, sell them on the idea of green roofs, and then connect them with green roof design, build firms, collect a bit of a commission, and then move on from there.
That evolved very quickly into offering the same for rooftop solar, living walled gardens. And then over the years, it's grown and grown in line with the sustainable buildings concept!
I offer them a range of sustainable green roof and green building consulting services from design, build or long term maintenance for green roofs, living walls, rooftop solar, advanced stormwater systems for rooftops, and all of the above.
MM
In the end you are offering a kind of vertically integrated service / product offer which makes complete sense because once someone jumps into bed with you, it's natural that they should want a complete service from one trusted sustainable green roofs supplier.
You mentioned New York, we can hear background noise from New York, which sounds brilliant, but like tell me what's happening at the moment there. What's the scene looking like? How have you seen a change over the last few years? And where do you see it going? Like what's what's happening there specifically in your location, your city, your hometown?
AB
Look, COVID cannot be ignored. It probably finds its way into every episode of your podcast in one way or another right?
How I've seen it specifically impact our industry, our multifamily residential, Co Op, condo buildings and whatnot. Those folks who perhaps had declined to move forward with a rooftop amenity space or green rooftop amenity space in the past, found themselves calling us back up during COVID saying, ‘Okay, we get it now, we really see the value in having a private rooftop garden space exclusive for residents in the building where they can access without having to go out into public.’
And we used to sell it as ‘Hey, wouldn't it be nice to take a mug of tea up to your own green roof rather than having to go out to a city park and people really understood that during COVID.
So, demand for outdoor terrace spaces and for green space has really increased from that perspective. Similarly with everyone quarantining and working from home more so than ever, people are critically evaluating their indoor surroundings and asking whether how this space contributes or maybe negatively affects their mental health.
And so people are now starting to click into realizing that plants are a great prescription for the quarantined and so people were looking for ways to bring greenery into their home, whether that's on a terrace in the form of a little green roof on the rooftop, a lush green roof or indoors as living walls.
Because you can only fit so many potted plants on your windowsill or on your bookshelf and then you run out of space and if you want to go heavy with the greenery you've only got so much floor space but a lot of people have excess wall space so you could build a living garden wall really lush out green out your indoor space but not consumed that valuable footprint real estate.
MM
That talks to the ‘mental wellbeing’ and healthy buildings side, the human aspect to it, I think we can all connect with that at a very primal level but there are economic and environmental benefits, too. How do you see those two factors playing into a decision making process around installing one of these green roofs in a sustainable building, whether or not they are pursuing a green building certification?
AB
Sure, it really depends on which stakeholder we're talking about Because the New York City government are motivated for people to build green roofs for a host of reasons. Private property owners and building owners are motivated to build green roofs for a very different set of reasons.
The thing I like before we get into those reasons about that situation, though, is with green roofs, regardless of which set of benefits you're most interested in, and what's motivating you to buy the green roof, you get the other benefits as part of the package.
It's like if you and I buy the same swiss army knife, you may be buying it for the Phillips screwdriver and maybe I want it for the tweezers and the scissors. But we get each other's tools when we because we're buying the same swiss army knife.
most green roofs being built in New York City, if we're being perfectly honest, are by wealthy people who are building these lush green oases, you know, terraces or rooftops because they want a calm, green natural space on top of the city where they can drink rose wine spritzes with their friends and relax.
As the environmentalist I like green roofs because they're managing stormwater, sequestering carbon, providing habitat and food for migratory and local species and whatnot.
But whether the clients care about that stuff or are aware of that stuff or not. Either way they are providing the city or the general public all of those benefits when they build their swanky rooftop garden oasis, as far as direct benefits, and this is how I've definitely seen things change in New York dramatically.
speaking from the city perspective, many of the older, larger North American cities are battling a stormwater management crisis. And that's because our sewer systems were designed 150 years ago, when there was only a fraction of the pavement space and everything was, you know, the island of Manhattan was mostly farmer's fields above the absolute downtown.
So rain didn't really go into the sewer, it all landed on the open green space. And 150 years ago, there was only a fraction of the toilets now, you know, population a 9 million that's a lot more toilets in the world 150 years ago, so there's nowhere for the rainwater to go except hitting pavement going into storm drains or hitting rooftops and going down the scuppers into the sewer drain. And there's way more wastewater being generated, and then going being sent through indoor plumbing directly down into the sewer.
We in in several North American larger cities on the east coast, the older ones at least like Toronto, New York, DC, Philly Chicago, we have what's called a combined sewer system. That basically means there's it's a single pipe system, so rainwater and toilet water all goes down into the same pipe on a dry day where you can still manage to process all of it at the wastewater treatment facility.
But in New York City, for example, it only takes 1/20 of an inch of rain that's about between one and two millimeters of rain is all that's required to max out the city's wastewater pipe going down to the wastewater treatment facility. And so the excess rather than having it pushed back up and through people's toilets, and flood their homes, or push back up through the roof through the storm drains in the streets and flood the streets, the excess is just allowed to flow over through what are called combined sewer overflow points. And there's 460 of these combined sewer overflow points lining the New York City Harbor. And people put really, really gnarly stuff down the toilet, way worse for our health than feces and urine.
We're talking like, you know, illicit drugs, expired birth control medication, cancer medication, broken glass batteries, I mean, people are animals, and they put awful stuff down the toilet in the privacy of their own home. And all of that is flushing out into our local waterways here in New York and the local waterways of all the other cities I just mentioned to you, whenever there's more than two millimeters of rain in the city or you know, 1/20 of an inch.
So, that is a major problem that cities are being fined at the federal level to clean jp. And so now the options are, you know, tear up the sewer system and put a new one in which is preposterous that could never possibly happen to New York, or you know, put down more parkland. But you know, every inch of New York City's developed you can't tear up a city block and put a new park but nothing says these Park parks have to be at grade level and nothing says these parks have to be continuous they can be distributed parks cut up into tiny places and put up on top of the rooftops where the rainwater lands. And so basically green roofs, these many little rooftop parks act as sponges, they absorb the rainwater right where it lands on the roof.
Half the water never makes it off the roof because it's just used for photosynthesis and Evapo transpired by the plants up into the atmosphere. And the rest of the water takes its time to percolate through the system.
Green roofs clean and cool the air, sequester carbon and provide rooftop habitats for birds, bees, bats, butterflies, and much more.
So there's a whole host of environmental reasons why cities like green roofs, they also like rooftop solar here in New York City for reasons that should be obvious by now.
So a big change that I've seen recently was as part of New York City's Green New Deal or the climate mobilization act, I and a few other people testified at City Hall back in January 2019. In support of a few key pieces of legislation, they were all unanimously passed, but a big one that's going to have a major impact on the skyline of New York City, specifically, its rooftops is something called local law 9294. And this basically mandates that all new construction and certain retrofit projects must install either a green roof or a rooftop solar, there are certain exclusions if it's too sloped, or if you don't have the structural capacity or if it's too shady, or whatnot. But nonetheless, this is going to have a massive impact in in driving change to the greening of New York City's rooftop.
So this is a big change, it only really came into effect about a year ago. And so this is for all new building permits. And as buildings start to go up, you're going to see the number of green roofs and solar installations in New York City, honestly skyrocket. So that's an exciting, exciting change here.
MM
That's the city in a way laying out his vision for the future in terms of how roofs need to play a functional role in protecting the city itself and the urban landscape from from climate change from the negative impact that we're bringing, just by building cities of this.
AB
Absolutely. I mean rooftops are the front line, whether you're talking about the photons from sunlight or the raindrops from clouds, one of the first things they're both hitting is the rooftops in the city. So that's a frontline defense to capture these photons and use them to generate electricity.
I may also add that as you capture these photons on solar panels, that means they're not hitting the roof membrane and not heating up the membrane and not sending all that latent heat baking down And driving up air conditioning bills in the summertime.
Green roofs do the same thing. The leaves of plants are actually the plant solar panels because that's their food energy, if you will, from the photons and use it to photosynthesize, and grow plant more plant matter. But again, they're intercepting those photons or preventing them from hitting the roof membrane - plants can act as the first line of defense yet in New York City, less than 0.01% of rooftops are greened in any way and it's a very much out of sight is out of mind situation.
New York City is like a lot of other really expensive urban centers around the globe. It's absolutely obsessed with real estate, the cost of real estate, the cost per square foot to buy or own or rent or whatnot. And yet no one does anything with the rooftops they max out every square centimeter of their apartment yet building rooftops are completely undeveloped - I find that odd but that's changing as the city realizes it's a massive wasted opportunity to solve many problems that plague urban centers around the world.
MM
I sometimes see a rooftop used for an element of food production, whether that food is then consumed by those living in the building or whether it's distributed or handed out to those in need in the local area, whatever it may be.
Do you see that as an exception rather than The rule when it comes to how to utilize a rooftop, or are there real benefits in terms of making a more resilient city so that there's more local kilometer zero production happening on site around NYC around Manhattan?
AB
It's a bit of everything - all of the reasons that I've mentioned above that why city municipalities, city governments like green roofs, it doesn't matter whether the plants, at the very top layer of the green roof are ornamental amenity space plants that are there just for aesthetics, or if they're there as food crops, they're still performing all of the critical functions and offering the same benefits as every type of green roof does in terms of stormwater management, sequestering carbon, insulating buildings, providing habitat for species and whatnot.
I think urban food production on rooftops is a massive opportunity for cities around the world - we encourage all of our green roof clients to dedicate at least some portion of their green roof to a little urban agriculture culture plot
As I'm looking out the window right now, my neighbors are Brooklyn Grange - one of the largest rooftop farms in the world, here in New York. So that's a fully commercial operating farm on top of a commercial building. But there's plenty of green roofs in a city where maybe it's an amenity space on a multi a private, you know, residential building, and maybe the residents will ask us to dedicate, you know, a few square meters off to one corner, for like a little tomato plant growing a little plot there or something like that.
Yeah, there's plenty of opportunities to create sustainable green local jobs, and then produce food that's either used if it's in a commercial entity, like for the the building tenants themselves, or can be sold or distributed or donated to the local community. And it definitely speaks to improving the resiliency of the city.
Most cities are importing their food from other cities or other countries. And the more that you can grow locally, the less reliant you are on other cities for your food production. So you're certainly becoming more self sufficient in that regard even before considering the transmission emissions, I mean, if we're trucking, you know, fresh fruit in from California, it's got to come all the way across, it's not quite as fresh by the time it gets here, it's also expensive to truck it in, and there's certain carbon emissions related to all that transportation to ship it over. So all of that is eliminated, when you can be growing right off the roof.
farm to table is great but roof to table is even better
Matt Morley
So the key point I'm picking up there is that it's not one or the other, the way these natural roofs work is that they can do multiple things at the same time. So you're not neglecting for example, improved biodiversity by adding an agricultural component to your green roof. In fact, it's multiple layers of benefits rather than one to the exclusion of anything else.
AB
green roofs perform multiple functions with societal, environmental, building operations, and mental health benefits, all simultaneously.
And, and passively, you know, whether we like it to or not, again, the people who are if a wealthy couple just wants to build a fancy rooftop garden amenity space just for their own family, let's say those plants are still sequestering carbon cleaning and cooling the air you know, thermally insulating the space which reduce improves their energy efficiency and probably reduces their reliance on fossil fuel power plants.
And again, maybe they don't care about all of that maybe they're not aware of it, maybe they don't care for a lot of our clients, we will if in in lieu of any input from them around plant species selection, we are going to lean heavily towards favoring native and adaptive plant species so as to you know, improve conditions for local and migratory species
If anyone wants to deeper dive on this topic, there's a book called nature's best hope. And it's by Douglas Tallamy, he speaks extensively on the topic of the urgent need for people when they're doing landscaping, in their homes, around their buildings, whether it's on the rooftop or at grade, using native plants that are native to the area or adaptive rather than bringing in these plants that are not native to the region and maybe are going to require quite a lot of resources in order to keep them alive and whatever your respective microclimate is.
And then also they could be potentially, you know, we, the concrete jungles are creating these like these, these these blot out of blue down at a loss for words here, these these scorched earth kind of patches all around the globe where nature can't really thrive, or birds, who maybe after, you know, hundreds of generations are of programming are used to flying that migratory path when they're used to touching down there to rest, or seek food or, or, or or procreate, they can't do that now, because it's all some urban sprawl is created a concrete spread.
And so anything that we can do to recreate what they're used to having there as far as greenery that houses the bugs that they want to eat, or provides habitat for them to build nests, or rest, anything we can do to help with that will reduce the impact that our urban centers and urban sprawl are having on the local ecology.
Matt Morley
So when you zero in on solar panels, for example, where you're really integrating a technical component, perhaps more of an engineering angle, there, the benefits presumably reduce and focus more on the environmental impact the economic play rather than nature. So when you're proposing those, what are the conditions under which you would typically propose solar panels to be in the mix or to be the dominant force on any given rooftop?
AB
I'll give you the highlight reel, but it's actually such an involved answer sometimes. And it's, it really needs to be determined on a case by case basis that, you know, years ago, we actually, we realized we were giving away so much upfront free consulting for buildings, because they would call up and say, Hey, we've got a roof Should we go green roof for solar, we see that you offer both. And there would just be such an involved process to determine which is best for them and their goals and their budget - we now offer it as a branched off consulting service, in advance of either building them a green roof or a solar, you know, we're sort of It's a discovery process, if you will, or a service.
On a really high level, there's a few things you know, we can either go process of elimination, like a lot of time, people will call up saying they want a green roof and I started asking them questions, and one decision or another or one element or another could kill the green roof project and green roofs, they get killed, they die on the vine all the time. And then that leaves them with what they feel is a useless rooftop.
I say, well hang on, there's always solar, you know, when it comes to solar money is falling out of the sky and solar panels are buckets. So your your roof is far from useless, it can be a great source of passive income for your building, especially now that it turns out that you can't build the green roof that you wanted for whatever reason.
So for example, solar panels are quite are quite lightweight, they're really only about five pounds per square foot. I'll let you translate that into kilos and put that on the show notes compared to say solar sorry, compared to say green roofs, which at their lightest are going to be say 15 pounds per square foot and but they get heavy very quickly.
As a little rule of thumb green roofs tend to weigh six and a half pounds per inch of depth per square foot. And a minimum at the minimum, you're the average green roof is three to four inches. So we're talking at least 18 to 25 pounds per square foot compared to solar that's five or six.
Now that to be clear, that's when the green roof is fully saturated or holding the most amount of stormwater that it's it's designed to from an engineering perspective. But that's not including. If it's meant to be a public amenity space and or just amended in official amenity space listed on the building certificate of occupancy basically, are you officially decreeing to the city that this is an amenity area for the building?
Because the moment you do that, in New York City, for example, you have to show that you have structural capacity at 100 pounds per square foot if people are going to be walking around up there.
So if you have a deck, and people are going to be congregating there with any regularity, and then you have greenery around it, and that's your green roof, you're going to need at least 100 pounds per square foot in the areas where the people congregate. And so a lot of buildings don't have that.
And so that's an a lot of building owners will say, well hang on, if we can't use it as an amenity space, we don't we don't want it as a green roof. And then that that's that's frequently what kills a lot of greener projects in New York City. So then you're left with solar?
MM
I'm sure it's a question you're asked often by clients, no doubt far earlier in the process than you might like. But inevitably, the economics of all this has to come into play at some point. There are some big numbers involved. I know. But why don't we just have a quick overview if we can have the financial side, and what we're looking at in terms of these green roofs, and how perhaps different sizes, if it's shapes or densities or planting strategies can all affect exactly how much the overall budget equates to.
AB
So that really ranges. I mean, it just depends on so many different factors. It's hard to speak absolutely about this, because it changes even within New York City, the exact same green roof technology, because beneath the plants was a wide array of technologies, the exact same green roof technology, in the exact same neighborhood of New York City on two very different buildings could cost $17 A square foot or it could cost $60 per square foot.
I'd say the two big the two biggest factors are economies of scale is massive for green roofs, because what a lot of construction projects make mobilization is a big one.
So to make an extreme example, if you're mobilizing a crew, maybe you're getting a crane permit, you put design hours and just to make an extreme absurd example, if you're doing all of that for one square meter or a one square foot green roof now just to make an example, right, the all those costs per square meter per square foot would be outrageous.
But if the exact same designer, same crane permit, same crew mobilization same design, ours is allocated over 500 square meters or 100 square meters or 500 square feet 1000 square feet, you can obviously see that that cost per square foot is going to drop like a stone.
Similarly with solar panels, oh that so but sticking with green roofs, the other thing that can really drive it would be access. So I mentioned there a second cranes, I mean, if we can crane the material up that's one efficient way to get a lot of material up to the roof very quickly.
However, depending on what part of New York City that you're in, that crane can cost anywhere from $5,000 a day to $40,000 a day. Depending on the permitting do you have to block off the road you have to build these protective sidewalk sheds so that people can still walk along the sidewalk underneath. So the crane costs cranes can either save you a lot of money with efficiency or kill the project with additional costs.
But at the other extreme, you know, sometimes for like a brownstone, like the classic brownstone roof. Sometimes the only way to get material there is for the installers to carry it on their back up a ladder through a hatch in the ceiling. And that's obviously that's not as efficient as a crane.
A good in between would be they have these things called blower trucks. And so basically a big almost like a dump truck but full of growing media or let's call it soil for now for the green roof that pulls up out front of the building. And there's a giant hose that can go up like six storeys tall, and it blows the dirt like a reverse vacuum from the truck up six storeys, and they just spray it like a garden hose, but it's dirt.
So that's a great way to convey materials up. And yeah, I'm kind of going all over the place here. But access and economy of scale as far as the square area of the project can greatly affect the cost per square foot of a green roof.
I'd say similarly, there's there's different types of green roofs, right? I mean, we have there's very gorgeous like alarmingly beautiful English Garden meadow looking things that you may see if a five star hotel is building a rooftop amenity space, they're going to want the highest end landscaping green roof up there possible and they're going to want it to look that nice and green and well kept for as many months of the year before the winter kicks in.
Contrast that so that's going to be very expensive on a per square foot basis. You know, you'd have like top of the top of the line automated irrigation to act as an insurance policy. In case there's not enough precipitation, you're going to want to have nice lighting and benches, paver stones, walkways a wide range of herbaceous and woody species and you know blue different you know, you're going to want to sink a lot of time and energy and money into the design of that, you know, you're going to want a Professionally licensed landscape architect attacking that problem to really make sure that it's looking absolutely banging for as many months of the year.
Contrast that with, say, a sprawling, single storey warehouse in an industrial park, who may be they never plan on going up there, they never plan on seeing it, they only want it because it's going to protect the roof membrane from UV degradation.
So they don't need to replace the roof membrane every 20 years. Instead, they replace it every 50 or 60 years. And all that green matter up there, as I mentioned earlier, is going to intercept the sun's energy, the photons and soak up that otherwise, he energy that's going to hit the roof membrane and beatdown for a lot of these single storey warehouses, their air conditioning bills are absolutely astronomical in the summertime.
And it's just to keep the plants sorry, the warehouse warehouse plants are operating at a comfortable condition either for the goods that are being stored inside, or for the workers that are in there. And if you just have a black tar bitumen roof, and the sun is baking down on that, and you're a single storey building, your AC bills can be astronomical, but a thin, basic crummy looking, you know, low hanging fruit bargain basement, green roof, that's only one or two inches deep.
And you have systems which are sort of in the cactus family, they're like drought tolerant, they're not the best looking, but they're the workhorse plant species and green roofs, if you just build the most basic green roof possible, and you could do that for you know, depending on the size of the roof, maybe, you know, 15 or $18 per square foot, that's before any tax breaks that are available, you could slash your air conditioning bills in that building by anywhere from 60 to 80%.
So that just from the air conditioning bills alone, you pay off that green roof in no time. And, and then again, you could just frankly, let it go to help you don't care what it looks like, you know, because it's not an amenity space, you don't really need to spend a lot of money upfront on expensive looking plant species. And you don't need to spend a lot of time maintaining it, you can just kind of let nature take it over and let it turn into a real nature roof so to speak.
MM
Okay, so then the flip side of that, surely is is the benefits and the return on the investment or just the outgoings at the front end. But what the owner developer landlord is getting back over the medium to long term.
AB
Yeah, from an accounting perspective, building owners see the rooftop as a cost center. No one thinks about their building rooftop making money from they just think, Oh, God, this damn thing is going to leak again. And the only think about is how much money they're going to need to reinvest to put another layer of patchwork and new waterproofing on top. And they don't realize and instead of being a source of headache and stress and a cost center, it can be a revenue generator and a source of joy.
You can catch money falling out of the sky, whether that's photons from sunlight or stormwater if you're in DC, it can be your piggy bank on top of your roof.
Building owners should be thinking of their rooftops as buckets instead of lids, because there's money falling out of the sky.
Matt Morley
I love that! You mentioned stormwater there.
I wanted to pick up on that topic because it's a big one in terms of sustainability and environmental impact. And there's clearly a lot of potential there.
So how do you typically talk about the stormwater angle on a green roof when you are discussing options with a client? And what are the overall benefits and opportunities there from your perspective?
AB
Okay, so they have a program in Washington DC, where they're basically stormwater. It's such a major issue in Washington DC, that they're basically those buildings who manage more than what building code requires them to in terms of the amount of rainwater that they can hold on the rooftop are awarded credits.
And those buildings who cannot manage enough rainwater on their property on their rooftop are fined exorbitant amounts of money. And then they basically then need to buy their way out of these fines by buying the credits from those people who have them for doing a better than basic building code level of managing stormwater.
And there's a there's a stormwater credit trading program in Washington DC around this topic. And I expect this as because the cities are falling like dominoes here in North America who aren't mandating green roofs for any number of the reasons I mentioned earlier.
And as you're going to see that stormwater becomes a bigger and bigger problem and as fresh quality water and cleaner waterways are becoming more prioritized, you're going to see stormwater credit trading programs like that implemented, and I and so what's happening is people are then realizing that they're, they are then motivated, especially at the beginning of design to turn their buildings into bathtubs that can hold as much water up on On the rooftop as possible, because the more that they can go about building code, that's just free money for that they basically get awarded these credits, which have real value.
And so green roofs can do that we have these called Blue roofs and blue green roof, you could basically have a system that looks like a milk crate, these plastic cells that can be, you know, anywhere from 10 to 60 centimeters deep, filling the rooftop and then on top of that, you put paver stones so that people can walk around and they just think it's a regular amenity space, but really below them could be half a meter of empty void space where rainwater is stored instead of cisterns in the parking lots are underneath the building.
And they are awarded annually, not an insignificant sum of money for doing so. Then the other thing we didn't talk about was green roofs when integrated with solar panels.
Solar panels lose operating efficiency when the ambient air around them gets too hot but Plants cool the air around them through through evapo transpiration So when you install solar panels directly on top of green roofing, the plants cool the air underneath the solar panels and help them to produce more electricity.
So even if you can squeak out half a percent improvement in the efficiency of a solar power plant a CFO of that company loves it. But if you can actually tell him, Hey, I'm going to reduce your efficiency loss by six to 8%. I mean, that's in the summer months, that is a massive amount of money. And so plus you didn't get so basically you have you have all the benefits of the green roof on the system, you have all the benefits sorry, the greener system, you have all the benefits of the solar system, and you get more electricity from the solar. So solar integrated, green roofs are big.
And then if you want to combine all of them that below that you could have the 40-60cm of rainwater retention and the blue roof hidden beneath immediately beneath that green solar green roof area. So there's so much going on and rooftops and so much is going to happen in the next five years that people are going to realize rooftops are a vastly underutilized resource to either make bank or or solve climate change issues or improve mental health. You know, you name it.