Alison: This is All Of It, I'm Alison Stewart live from the WNYC Studios in SoHo. Thank you for sharing part of your day with us. Last night, a bunch of us gathered in The Greene Space, that's WNYC's performance space for a live listening party with Jon Batiste. It was fire. You'll hear some of that music and conversation on the show tomorrow. We're going to gather in The Greene Space again on Monday, October 30th for a different reason. It's our first All Of It blood drive. Yes, it is the day before Halloween, so you can do a bloody good deed. That's on Monday, October 30th, from 12:00 to 4:30 PM.

New York City's blood supplies are critically low. You can help out your fellow New Yorkers, just sign up. Go to wnyc.org/giveblood, and there may be treats. I think there will be treats. We hope to see you there. That's in the future. Let's get this hour started with everything you want to know about green roofs. A lot of us are looking for ways to reduce the impact of climate change. For those of us who live in New York City, the clock is ticking, and not just because the planet is warming. New York City's Local Law 97, which sets goals for buildings, energy efficiency, and emission limits starts going into effect soon.

One big area of focus is city rooftops. In the summer, a blacktop roof absorbs and retains a lot of heat. These roofs can reach temperatures of 190 degrees, raising energy usage inside the building, and contributing to the urban heat island effect. There are a variety of ways to attack this problem from the top down. You can install energy-saving reflective paint, but that won't help with other climate issues like stormwater capture and biodiversity. Enter the green roof.

They've been around for a few decades, but more and more, they're being seen as an important weapon in our arsenal as we fight to reduce carbon emissions and lessen the impact of catastrophic global warming. Joining me now to talk about this is Dustin Partridge, he's the Director of Conservation and Science at New York City Audubon. He's also one of the founders of the Green Roof Research Alliance. Dustin, welcome.

Dustin: Thank you.

Alison: Also, joining us is Alan Burchell, the founder of Urbanstrong, a green building company in Brooklyn. Alan, welcome to the studio.

Alan Burchell: Howdy.

Alison: Hey, listeners, want to get you in on this conversation. Do you have any questions about green roofs? Give us a call, 212-433-9692, 212-433-WNYC. You can ask your question on air, or you can text us at that number as well. If you're considering a green roof, give us a call or maybe you have one, let us know. How's it going? 212-433-9692, 212-433-WNYC, you can reach us on our social media @allofitwnyc. Dustin, what is a green roof? Let's just start with baseline.

Dustin: Yes, so I guess in the simplest form, a green roof is vegetation on top of a rooftop. It's these little patches of habitat that have a lot of benefit for humans across the city. Obviously, they're very highly engineered and there are different elements that go into a green roof, which Alan can talk about, and it's most simple form, it's vegetation, soil, and something to keep everything on top of the roof.

Alison: Not in containers or people who are thinking.

Dustin: Not in containers, no, these are expansive areas. In some cases, they can look like sprawling fields and other cases they can be these little pockets of vegetation, a tree, a shrub, that covering of a roof in New York City or anywhere.

Alison: Alan, do you have a sense of how many green roofs exist in New York City?

Alan Burchell: In New York City, there's approximately 760 green roofs covering about 60 of our 40,000 acres of available rooftop space.

Alison: What are the benefits? What are the benefits? Sell me on the benefits of a green roof.

Alan Burchell: Sure thing. People always ask me, what's my elevator pitch for a green roof? I'm like, "Well, you got to give me a hint. Who am I in the elevator with?" Whether you're a building owner or the director of a school, or if you're a city planner or an occupant in the building, they've got a range of different benefits. I like to say that green roofs are like a Swiss army knife of tools for battling climate change and benefits for city planners, building owners and whatnot. There's two different buckets that the benefits fall into. There's environmental benefits, which Dustin can talk to at length, and then there's some more financial and building operational benefits.

To get started, they will thermally insulate the top couple floors of your building because the vegetation is literally intercepting the sun's photons, and rather than heating up your roof, the plants use it for photosynthesis. They sponge up stormwater, so you may hear of the term sponge cities. Green roofs are a great way to soak up all that stormwater and keep it from overflowing or sewers. They protect your roof membrane, so every long-term building owner knows that the uppermost layer of their roof, it's a consumable. That thing, the sun's rays turn it into Swiss cheese every 12, 15, 18 years.

When you put a green roof on top of your roof, it's like putting a case on your smartphone and you can elongate the lifespan of that roof membrane, avoid leaks, cracks, and repairs for an additional 30, 40, 50 years.

Alison: Tell us about the environmental impacts.

Dustin: Yes, so one of the reasons that we focus on green roof at New York City Audubon is because there are so many benefits of these green roof for New York City, for both humans and for wildlife, our strong focus is on birds. As Alan mentioned, and as we experienced a few weeks ago, stormwater is a huge benefit. We experienced that flooding a little while ago, and what green roof does for stormwater is it captures it and holds onto it. The plants use it for survival, it gets the water off of the roof.

Also, the pore space, basically the small area between the soil that's on the roof holds onto water and slows it down, so it doesn't enter our sewer system or flood our streets, result in sewage dumping into our local waterways. It cleans the air, they filter the air, they remove pollutants through just the plants being up there, they cool the city, then importantly, they provide habitat. Right now, we're actually in the middle of migration for birds, so we have birds moving through New York City right this week that are coming from as far away as Alaska.

They're landing on these green roofs to forage and find basically fuel to refuel their flight so they can continue down to South America or the Caribbean. Our green roofs provide that amazing element for birds, insects, and bats throughout the city.

Alison: Where calls are starting to come in. Let's talk to Alan, calling from Brooklyn. Hi, Alan. Thanks for calling in.

Alan: Thank you. I'm a member of Synagogue in Brooklyn, that is Unshaded, and it's about a half a block of elevated flat roof with great potential for solar, water retention, planting. I'm wondering if there are any programs that will assist not-for-profits in making this resource available for ourselves and possibly for the benefit of neighboring properties like solar energy, community pools, or things of that kind.

Alison: That's an interesting question. Do you know if there are any?

Alan Burchell: Yes. Absolutely, Alan. There's been no better time to develop your rooftop in New York City than right now. There are solar subsidies and finances and revenue opportunities at the city, state, and federal level that all stack together to can turn your rooftop into a very attractive, profitable revenue stream. Similarly, for green roofs, there's programs at the at the city level, two different programs at the city level, the Green Roof Property Tax Abatement, and the DEP's Green Infrastructure Grant Program.

We would have to look into the details and see if and how they could apply to a nonprofit. It's also worth mentioning that you don't have to choose between the two. Having a solar-integrated green roof and the exact same footprint, you can have your cake and eat it too. Definitely worth exploring, your open sunny rooftop, Alan, is a massive resource for you.

Dustin: To follow up on that actually off of, Alan, mentioned the green roof tax abatement. Depending, Alan, on where on where your building is you could get a pretty highly increased rate of abatement, which is a benefit that goes to priority districts in the city. Priority districts are areas that have been identified as having high-related incidents of heat-related mortality, a lack of green space and stormwater issues. Those areas get increased attention for greeners because there's so much benefit to the city from installing a greener front building.

Alison: Where would you find out if you were in that one of those zones? How could you find out?

Dustin: There are a couple of tools available, so you can go to the DOB or you could go to greenroofsnyc.com, which has a tool and a function that's been created that you could actually search your address to see if your building is within one of those priority districts.

Alison: We're discussing green roofs with Dustin Partridge, director of the Conservation and Science for New York City, Audubon, and Alan Burchell, founder of Urbanstrong. Listeners, if you have a question about green roofs, give us a call. These guys can maybe answer them, 212-433-9692, 212-433-WNYC. You can join us on air or you can text us at that number. If you're considering a green roof, or maybe you have one, we'd like to know about that too. 212-433-9692, 212-433-WNYC, that is our phone number in our text line.

Social media available as well @allofitwnyc. I have a bunch of questions, but we're getting texts in. #greenroof, is it true that AstroTurf is even worse than Blacktop in terms of environmental impact plastic slough and heat generation? Yes. No, maybe so.

Dustin: It's interesting. I haven't heard that before, but I wouldn't be surprised if you weigh the costs and benefits of the whole system and the creation of plastic versus blacktop. What it has been shown to be true is that with the installation of real vegetation, even at a small scale that can have benefits that are for the building or for the whole city.

Alison: Someone wants to know, will I see bees, hummingbirds, ponds?

Dustin: Oh, absolutely. Yes. One of the things that we do with New York City Audubon is we monitor greeners around the city. Some of my own research for years. We are seeing biodiversity thrive on top of our roofs. We have actually all of those. We actually just recorded a ruby-throated hummingbird on the Javits Center the other day. They're pretty frequent visitors of green roofs and actually at the Javits Center, where they have an extensive roof which is a large sedum field as well as an apple orchard and a farm. They're now have 62 bird species there.

On most of the roofs in the city, we've also recorded five species of bat, most commonly the eastern red bat, and hundreds of species of insects, including dozens of native bees. If you go out into a green space in the city, you can look around depending on the time of year that you're out there, you can see all sorts of wildlife that you maybe wouldn't expect to see in New York City.

Alison: Alan, let's get some nuts and bolts. How do you install a green roof? How do you start? Let's start there.

Alan Burchell: Yes, I would call a professional. We, at Urbanstrong, will happily walk you through your options. First and foremost, you need to figure out if your roof is a good candidate for it because the reality of it as much as I'd love to ding my wand and have green roofs cover every single rooftop in the city, there are certain constraints because they sponge up water as Dustin was explaining. They have a certain weight to them and not all rooftops can handle the additional capacity, the weight of a green roof. That's regardless of whether you want to use it as an amenity space.

If you want to use it as an accessible amenity space for certain sizes, certain numbers of people then the weight requirement, the structural requirement is that much higher. One of the first things we're going to recommend is that you have a licensed structural professional engineer survey your rooftop to identify what are you working with here, what really are your options now? Even if you don't have the capacity there, you can still, there are ways that we can get creative with the engineering, bridge between the parapets or build little decks above the columns and the joists and whatnot to create space there.

Yes, you need to figure out if it's possible. Then we walk you through a whole design development process and ask you what your goals are because there's a spectrum of green roofs from the simple, shallow, extensive green roofs that are lightweight and not necessarily award-winning for their aesthetics all the way to the other end of the spectrum where they're quite lush, they're quite beautiful and depending on the building's type and its programming and its goals, different people are going to want different green roofs.

Yes, like a sprawling warehouse in Greenpoint that just wants to protect their memory and slash their air cooling bills in the summer, they're going to build a different green roof than say a co-operative condo that wants to build a nice accessible amenity space. We need to understand their goals and walk them through that process.

Alison: I would think if I were in the top floor of a co-op and someone brought this to me, I'd be like, "Oh no, not on top of my apartment."

Alan Burchell: Why?

Alison: Just in terms of, you said, the weight, that idea. How would you assuage somebody's concerns like, "Hey, you're going to put this above my apartment."

Alan Burchell: Sure. Usually, the concerns for those people on the top floor are noise, weight, and leaks. We have an answer for all three as you might imagine. First off, the structural engineers, the city, the department of buildings, is not going to let anything get built up on your rooftop that would in any way pose any risk or danger. As Dustin said earlier, these are highly engineered systems, they're very predictable. We know exactly how much they weigh when they're dry, how much they weigh when they're wet. That's a non-issue that's taken care of.

Secondly, as far as leaks, people say, "Oh, a green roof up on my roof, the sponging up stormwater sounds like it might cause a leak." My answer to them is, "Well, would you not put a case on your smartphone because you're worried the case is going to scratch your smartphone?" It's quite actually the opposite. The best way to protect your roof membrane from either people walking around on it and causing a rip or the sun turning it into Swiss cheese is to bury it under several inches of growing media vegetation, and all the different layers in a green roof.

Then secondly, noise. If there are going to be people walking around up there, it's on top of several inches of green roof or over pavers. We have ways of spreading out and deadening that low-frequency muffled footstep noises.

Alison: Maintenance level from 0 to 10, what do you think of maintenance of a green roof?

Alan Burchell: Yes. Maybe people could budget for roughly, roughly a dollar per square foot per year. If you've got a 4,000-square-foot roof, it's going to be about $4,000 a year. People spend money on their landscaping down at the grade level. This is rooftop landscaping. Now, if someone comes to us and says, "We're not building it for aesthetics reasons, we're not building it as an amended area, we don't frankly care what it looks like," then we can let it grow wild because it's still going to perform all of the various environmental and building operational efficiency benefits that we were discussing.

But if it's going to be regularly accessed like on a hotel amenity space or a restaurant, or you want it to look nice then sure, you're going to invest a little bit more per year in the maintenance of it.

Alison: Before I get to one more call, let's say someone is thinking about installing a green roof. If I were to think of installing a green roof, I'd think, "Oh, this is great, but what if something goes wrong?" Is there infrastructure to help when things go south?

Alan Burchell: Sure. Regular maintenance can check on this but it is important to understand that you know these are thousands and thousands of green roofs have been built all over the world, particularly in Europe. These are tried and tested. They're approved by the Department of Buildings. These are highly engineered systems that you know for the most part things don't go wrong. We've been designed against it. All of the various things that could potentially go wrong, the design of green roofs has been iterated over decades to design against those things from growing wrong.

We can install a leak detection system, for example, that if there did happen to be a fluke leak, we can pinpoint it into something in the area of like a laptop and then open up that, surgically open up that bit of green roof, perform the repair on the membrane, and close it right back up. That's just one example.

Dustin: When we say that they're highly engineered, this is even down to the soil. We talked about soil and substrate on green roofs, but that soil is specifically designed to be lightweight and be able to retain moisture and grow the plants that are necessary in that depth, whatever depth that might be. Because that weight that Alan has been talking about, that basically, the weight that a building can hold dictates how much substrate you can put onto a roof and then how much vegetation, what types of plants you can put in. Then that has effects on what sort of wildlife can use it and the benefits that come out of it.

Alison: Let's talk to Mary Ann calling in from the East Village. Hi, Mary Ann. Thanks for calling All Of It.

Mary Ann: Hi, Alison, how are you?

Alison: I'm doing great. Speak up so we can hear you.

Mary Ann: Oh, can you hear me?

Alison: That's great, yes.

Mary Ann: This is such a great idea, I'm so excited. I have a couple of questions. First of all, are there any tours you give to show people the green roofs in New York?

Dustin: Yes. At New York City Audubon, we do have occasional events where you can go out into some of the green spaces that we monitor and where we partner. There is also a system in place at the Javits Center, which I think it ends around now in October, but for a fee of about $5, you can get a tour of their incredible space. There are other sites such as our partners, the Newtown Creek Alliance on Kingsland Wildflowers at Broadway Stages, which is a roof that New York City Audubon helped to develop, that they have open events that you can get out there and visit.

It's an incredible, that one in particular is an amazing site because it has native wildflowers growing amongst a very industrial neighborhood and it's quite the sight to see.

Alan Burchell: I also absolutely have to plug Cities Alive. The industry advocacy group for North America for both green roofs and living garden walls is called Green Roofs for Healthy Cities. They have an annual conference called Cities Alive. It moves between cities and this year, it's in New York City. It's next week and part of the programming are several different farm tour options. Go to greenroofs.org or Google Cities Alive and look for that tour information. You can buy tickets on a piecemeal or come for a whole week of trade show, conference floor.

We're actually having an event at Urbanstrong at our office in the Brooklyn Navy Yard. There's tours of the Brooklyn Grange Farm, our neighbor's next door, one of the biggest rooftop farms in the world. You can tour that. Yes, check out Cities Alive.

Alison: We're talking about green roofs. If you have any questions, give us a call. 212-433-9692, 212-433-WNYC. You can also text us at that number. If you're considering a green roof, give us a call or maybe you have one. Let us know about the experience. 212-433-9692. You can reach us on our socials @allofitwnyc. We'll have more after a really quick break. This is All Of It. You're listening to All Of It on WNYC. I'm Alison Stewart. I did want to let you know that voting is underway for a new house speaker. WNYC and NPR are covering it. We'll have more during the news headlines at 2:00 PM.

Right now, though, we're talking green roofs with Dustin Partridge, Director of Conservation and Science at the NYC Audubon, and Alan Burchell, founder of Urbanstrong. We are talking about green roofs. We've gotten texts about vegetables. Is a vegetable garden possible as part of a green roof?

Alan Burchell: It's very possible. A green roof is a stack of many different layers, a drainage layer, filter fabric, the engineered media, and on top of all those layers whether the plants are ornamental in nature or food crops, it doesn't matter. It's still a green roof. It's still eligible for all of the same financial incentives, performs all the same building efficiency, improvement benefits and environmental benefits. Yes, rooftop open-air soil-based farms are a big thing. Our friends at the Brooklyn Grange and the Navy Yard have a large farm.

The Javits Center has a very large, Justin can talk about this, but an open-air rooftop farm and a food forest on top of the roof. Yes, they're everywhere. Definitely extremely possible and something we really encourage building owners to consider.

Dustin: Yes, that Javits roof, the farm that Alan mentioned, it's so far this year, last I checked, it had over 500 pounds of apples come off of it. I think it's approaching 16,000 pounds of produce coming off the farm portion. There's a lot of potential. Obviously, not everything will be able to be at that scale, but you can certainly grow vegetables and crops on roofs.

Alison: Let's talk to Benton in Crown Heights. Hi, Benton. Thanks for calling All Of It.

Benton: Hi, how are you?

Alison: Doing great. I'm glad you're calling in. Tell us about your green roof.

Benton: Let's see. We have three green roofs on a couple of buildings at Crown Heights that we installed in 2002, two different green roofs. One on a 25-degree slope and one, just a flat roof. Then in 2005, we did another 3,000-square-foot green roof. All of our roofs are, I guess we'd call it extensor, which is 4 inches of volcanic rock and compost mixed. I don't know. We're very happy with these. One of the roofs have had a little bit of a leak, and it was tricky to locate that. Technology lets you see water with little cameras and things, infrared stuff. You can locate areas and dig up areas.

I would say something important is that flood test on the beginning of any of that to really, really make sure you have a good roof membrane and do the layers that is recommended. We've had really zero maintenance. It's just all rooftop, like mountain plants that just resilient. We don't water it. We don't do anything. It's really incredible.

Alison: Benton, what impact has it had on energy bills?

Benton: We haven't been looking at that. We've had some passive house design consultants look at some of the different areas. I wouldn't say it's a huge benefit. Your proper insulation is going to do the best but in terms of sound and really stormwater management was our reasoning. It wasn't for insulation. That's like a little extra you get the insulation. Stormwater management and still these crazy rains we've had in the last six months, two real big ones, they've managed. I can only hope that it's helped a little bit on the runoff that happens right at the beginning.

It'll store that water for a little bit and then it gets rolling. If everybody did it, we would help with what's coming down the pipeline.

Alison: Yes. I have one more question before I let you go. What is something you wish someone had told you or you knew before you installed the green roof?

Benton: Nowadays, they have soil-blowing machines, and that can get the soil up to the roof easy and quickly. When we were doing it in 2002, they didn't really have that. It was a lot of mixing on the ground and hoisting-up [crosstalk]

Alison: These guys are smiling and laughing in here as you're describing it. Why are you guys--?

Benton: In 2005, I think when we did our second one, there was an 18-wheeler that blows mulch at malls and stuff. It could go up four stories and blow it all around. It was done incredibly quickly compared to the hoisting situation. My main thing would be really test your roof and have a good membrane because you're basically saying goodbye to that membrane forever because it's under that soil and you want it to be tight.

Alison: Interesting.

Alan Burchell: I mean you'll never replace that membrane again for potentially in your lifetime, but depending on how old you are. Rather than replacing that membrane every 15, 18, 20 years, it could last for another 60 years. You might as well invest in a really good, sturdy membrane. Now, green roofs can go on top of a wide array of membranes. Some of them let you green right to the edge, like right to the parapet wall. Yes, I'm just laughing because I know how easy it is now to reverse vacuum below that engineered soil, up the side of the building.

It can go up five, six stories compared to craning it up or carrying bags of this stuff on your shoulder, up the hatch, onto the roof. It just could be awful, but instead, it's so easy these days.

Alison: Let's talk to Marcia, who's calling in from Brooklyn. Hi, Marcia. You're on the air.

Marcia: Hi, how are you?

Alison: Doing great. What's your question?

Marcia: I'm really excited about this topic. I reside in the Brooklyn, Crown Heights, Bed-Stuy area. Of course, there are a lot more Brownstones there. As a Block President for one of the blocks there, I was just wondering, how do I convince homeowners to actually look at what this can actually do for their homes? Because, of course, these homes are a lot older. You have answered a lot of the questions I had as far as vegetation and whatnot. As we look forward, we look to what actually what is coming ahead, where food insecurity is of the concern.

How do I basically format the conversation piece to be able to actually to even taking a look at this?

Alison: Yes, I'm going to dive in. We had people who are renters calling us saying, "Oh, I would love to have them. A long-time renter, I'd love to have this, but I don't own the building." When you're thinking about that, when you're somebody who's a block association where there are a lot of renters, what would you suggest?

Dustin: Yes. We often help out at New York City. We connect with different residents around the city. One of the first conversations is like Alan was saying, is figure out the goals of the project, so you can get a feel for the different residents in the building and figure out what might work. From there, you could look and design the green roof and design the approach to it that may most benefit the property. We're also always helping you to come out and help and explain what those are and having somebody that's very familiar with green roofs, it's always good to help guide those retrofits.

Alison: All right, I'll throw the skunk on the table. Who's against green roofs and why?

Alan Burchell: There's Local Law 92, 94 that got passed as part of the Climate Mobilization Act, started mandating that most new construction and certain retrofits install on the rooftop what is called a sustainable roofing zone. This basically means they either need to fill the roof with solar panels or fill the roof with a green roof, and they, for a number of reasons, some of these building owners are resisting. A lot of people don't like being told what they have to do, full stop.

If someone comes along and says you must, like if you have a shady rooftop and solar doesn't make sense, then you have build a green roof, and if they don't know about the benefits of a green roof and they don't feel like investing in it or doing their homework, sometimes the first urge is to resist. What we've seen is a number of buildings reluctantly ended up vegetating the rooftop because of this rule, and then fast forward a couple of months or years, and they say, "Oh, actually, we really are benefiting from it. We're glad that the parents made us cedar broccoli." It turns out it's actually good for you.

Dustin: I think a lot of that comes from the initial sticker shock. It's hard to quantify how much benefit comes from a green roof because it's not always as easy as if you install and spend this much, what is my payout at the end? What's the ROI? Often that's an issue at first, but over time, there's benefit to the building, as we've talked about, as well as the larger public good that comes from having green roofs.

Alison: Are there any organizations? I mean, this is going to take money out of someone's pocket in some way.

Alan Burchell: It depends where you live. As Dustin mentioned, the green roof property tax abatement, that woman who called in was from Crown Heights. I mean, in Brooklyn Community District 8, that's a priority area where the city will give you back $15 per square foot that you build. It's a one-time abatement that comes off your property taxes. If it's a large enough building that we can get your design and install cost down to like $20, $25 a square foot, then taking 15 off of that means you're getting a pretty heavily discounted green roof.

Then, as Dustin said, in the way that there's many tools on the Swiss Army knife, there's many benefits to a green roof, and each one will have its own little return on investment that ticks up and up and up and can help you get a fairly attractive return on investment net.

Alison: Lisa in Queens has a green roof, and they're having a little bit of an issue and they'd like to ask your opinion on it. Hi, Lisa. Thanks for calling in.

Lisa: Hi, thank you. Good afternoon. I live on the second floor of the building, which is above the parking garage. The building was built in 2010. The developer put green spaces at the back of each apartment on the second floor of some of the apartments. Every time it rains, there are puddles in the yard. Basically, we have half lawn and half pavers. I was wondering what the problem might be or if the developer might have maybe cut corners and not put proper drainage in.

Alan Burchell: Right. To be clear, this lawn that's puddling water, you're saying it's above a parking garage and is therefore technically a green roof?

Lisa: Correct.

Alan Burchell: Yes, it sounds like you're having a drainage issue. I would, as part of a regular maintenance checklist item for green roof maintenance is we check to make sure that the roof drains. I mean, it's important to understand you don't bury a roof drain when you put a green roof on top of a roof. You defend it like Fort Knox. I definitely want to make sure that the drains are clear and free of any debris leaves or anything like that. Also, it is entirely possible that the contractor or whoever installed it did cut some corners or didn't install a proper growing media, like Dustin was saying.

I mean, you definitely don't use potting soil on green roofs. It's too heavy. It turns mucky. We've all overwatered a plant. This is a very porous, inorganic material that should promote effective rapid drainage so that the green roof is only holding the exact amount of water that it's engineered and designed to do so and that the excess, that when it crosses that point of full saturation. The excess water needs to be able to effectively drain across that roof. We could take a look at it from a maintenance standpoint. I don't know what your current maintenance plan or operations is, but it sounds like it could use some tweaking.

Alison: Before we let you go, Dustin, you are quoted in an article in the New York Times, "The New York City building is in the bird killing hall of shame, it wants out." Tell us a little bit more about this.

Dustin: We look at green infrastructure, green roofs as habitat for birds so all these migratory birds that are passing through the city, they need habitat to fuel their flights. Another major part of our work is focused on making the city safer for birds to migrate through when they get here. It's a city of glass and concrete. What we do is we work with buildings and on city legislation to make glass visible to birds and reduce collisions. The way that connects with green roofs is it's always important to have green roofs. If you have a nice view of a green roof, make it bird-friendly so put up a film, there are stickers.

Basically, these dot matrixes that you can put up on glass overlooking a green roof to ensure that it's safe because they're a very valuable conservation tool. Green roofs can help protect biodiversity throughout really North America and as long as they're done right, if they're bird-safe, they can have incredible value.

Alison: Alan, someone wanted the Cities Alive website again.

Alan Burchell: Greenroofs.org and then go to events.

Alison: Events.

Alan Burchell: Or just Google Cities Alive NYC.

Alison: Can you have a green roof/solar panel combination in suburban residential New York area? How does a green roof work if you have a copper roof installed?

Alan Burchell: Those are two very different questions.

Alison: Let's just take the first half.

Alan Burchell: Don't take the first half.

Alison: Let's take the first half the other half is very specific.

Alan Burchell: Effectively, the racking system that supports the solar penetrates down through several layers of the green roof and then fans out and so you have the weight of the green roof is acting as a ballast and it can weigh down the solar panels. Then interestingly, despite what you would think, solar panels actually operate at a higher electricity production efficiency when the air around them is kept cooler. Dustin mentioned earlier, one of the benefits of green roofs is they keep the air around them cooler through a process called evapotranspiration.

When you vegetate underneath a solar panel, you end up boosting the electricity production efficiency of the panel. Not only can you have your cake and eat it too but you can have more cake than, well, that metaphor goes off the rails really quick but you know what I'm getting at?

Alison: How long does it take to install an average-sized green roof? Think about the average size New York City building.

Alan Burchell: It's the permitting is the issue. The design and permitting that all takes months. People love to call us up the weekend before Memorial Day and be like, "Oh, I've decided to put a green roof for our party next weekend," and I'm like, "Geez, you should have called this in November." There's a lot of permitting design, but the actual construction can be on the scale of days or a week.

It really depends on the size but there's a lot of design permitting, engineering as the design development process that we take people through because a green roof is not a green roof is not a green roof, so we need to figure out what you want, what your budget is, what can the roof support, et cetera.

Alison: We've been talking about green roofs with Dustin Partridge, Director of Conservation and Science at New York City, Audubon; and Alan Burchell, founder of Urbanstrong. Thanks for taking all of our listeners' calls and for coming to the studio.

Alan Burchell: Thank you.

Dustin: Thanks for having us.

Alan Burchell: It's been amazing.

 

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