By Christian Bergland, Projects Associate, BE-Ex
To combat the climate change-amplified threats of rising seas and supercharged storms, the New York City Council recently approved a $1.45 billion plan to build a sea wall along the East River. This plan is the latest in a decade of climate action by New York City aimed at reducing New Yorkers’ vulnerability to climate change. This process is known as enhancing resiliency.
Many of the City’s resiliency projects were born out of Hurricane Sandy recovery efforts, limiting damage from the next storm while cleaning up after the last one. Destroyed by Sandy, the Rockaway Boardwalk was rebuilt above the 100-year floodplain and includes resiliency features to reduce coastal erosion, both protecting area residents and enhancing’s the beach’s ability to withstand future storms. The US Army Corps of Engineers will take a similar approach when it breaks ground on the Staten Island Coastal Storm Risk Management Project in 2020.
The City’s resiliency efforts are not limited to the waterfront. Partnering with local utilities and the MTA, the City is working to simultaneously modernize and harden critical infrastructure. One of these projects recently went viral when the MTA filled a subway entrance with water to test newly installed flood gates.
In the South Bronx, the Hunts Point Energy Resiliency Project aims to provide a reliable supply of electricity to the City’s primary food distribution hub using solar, energy storage, and backup generators. These are just a few examples of the City’s broad application of resiliency strategy, aiming to protect New Yorkers in the face of increasingly frequent, destructive, and costly weather events.
While the projects highlighted above focus on New York City’s large-scale resiliency efforts, enhancing resiliency can – and should – happen at a smaller scale as well. Buildings – our focus here at BE-Ex – represent one major opportunity area for increasing resiliency across the city. With climate change increasing the frequency of extreme weather events in the form of storms, heat waves, and cold snaps, the New York City Mayor’s Office of Resiliency has issued design guidelines to help ensure that buildings and infrastructure are prepared to withstand the impacts of climate change over the coming decades.
Designing for Future Storms
The best way to prevent flood damage is to avoid building in flood zones. Unfortunately, much of New York City’s building stock was constructed during an era of lower seas and fewer, less powerful storms. With space at a premium in the five boroughs, wholesale relocation of vulnerable buildings is not an option.
Accordingly, many homeowners have elevated their homes to mitigate future flood risk in the wake of Hurricane Sandy. While this approach can be effective, it is also expensive – costing between $10,000 and $100,000 per structure and an estimated $10 billion for all at-risk residential structures. Elevating mechanical equipment to the first floor and installing flood vents or backwater valves represent more affordable alternatives.
Others have gone above and beyond in future-proofing vulnerable structures, adopting a variety of innovative, climate-resilient architectural approaches. Architect Illya Azaroff’s Hurricane Strong Home in Breezy Point, Queens is just one such example. Blending seamlessly into its surroundings, Hurricane Strong rises 15 feet above sea level – three feet above projected flooding – while incorporating a number of measures to help protect it from future storms.
Photo credit: +LAB Architect
The building’s frame, foundation, and siding are all constructed from concrete, ensuring the building can withstand high winds and floodwaters. In addition, the home features windows rated to sustain impact and backup power generators in case of power outages. This model is difficult to replicate at scale, as it requires rebuilding from the ground up, but employing its design philosophies could strengthen both new and existing homes throughout the five boroughs.
Designing for Temperature Extremes
Flooding is not the only climate change-induced threat facing NYC. Extreme heat endangers neighborhoods across all five boroughs, with low-income communities bearing the brunt of this risk. Income tracks closely with heat vulnerability, as low-income New Yorkers often lack adequate air conditioning (New York City’s multifamily buildings usually feature centrally supplied heat, but rarely feature centrally supplied air conditioning). For those who do have air conditioning, operating it for a long period of time – as during an extended heat wave – can be financially prohibitive.
Extended heat waves also strain our aging electric infrastructure, resulting in blackouts. New York City typically experiences peak electricity demand during heat waves as New Yorkers desperately try to cool down their homes and offices. When demand overwhelms our electric grid, the power goes out. We saw this firsthand in the summer of 2019, when more than 50,000 Con Ed customers were left without power for days during an extended mid-July heatwave, putting already vulnerable communities at even greater risk of harm.
Improving a building’s envelope – the barrier between the inside and outside of a building, including its walls, windows, and doors – is one of the best ways to minimize strain on the electric grid, lower energy bills for tenants, and enhance comfort for building occupants year-round. Envelopes play a crucial role in keeping heat outside of a building during the summer and keeping it inside during the winter.
Poorly performing envelopes are all too common in New York City’s aging building stock. Many of New York City’s buildings were constructed in an era of cheap fuel and with a poor understanding of thermal bridging. Due to these factors, many buildings were constructed without adequate insulation, wasteful by design. Wasted energy leads to increased energy use and higher energy bills, with low-income communities often the most burdened by energy costs.
Envelope upgrades can mitigate these issues. Even marginal improvements to underperforming envelopes can offer major energy savings and comfort benefits. Improvements like air sealing windows, doors, and air conditioners, adding insulation to targeted problem areas, and installing cool roofs, can all be relatively inexpensive and straightforward while significantly improving a building’s energy performance and resiliency.
Building operators aiming to truly future-proof their buildings in the face of temperature extremes can look to the Passive House design standard. Passive House and its associated standard for existing buildings, EnerPHit, utilize high performance envelopes to dramatically reduce energy demand. Passive House designs integrate high performance windows and doors and airtight envelopes while minimizing thermal bridging. High performance envelopes designed to Passive House standards offer passive survivability benefits, maintaining internal comfort and allowing occupants to shelter in place if utilities are cut during periods of extreme heat or cold.
BE-Ex’s Pursuing Passive case study examines a hypothetical EnerPHit retrofit on an existing building. With a system-by-system breakdown of high performance upgrade options, Pursuing Passive illustrates the benefits and challenges of designing to the EnerPHit standard. Even in scenarios where meeting the EnerPHit standard is not feasible due to cost, complexity, or occupant disruption, building operators can select certain elements to include in their buildings, whether they are constructing a new building or retrofitting an existing one. Doing so enhances resiliency, limiting strain on the electric grid, lowering energy bills, and making for healthier, more comfortable interior spaces.
Rooftops for Resiliency
Outside of high-performance design, New York City’s rooftops represent another opportunity for building decision makers to enhance resiliency citywide. Per the Climate Mobilization Act, passed in April 2019, New York City building owners conducting major roof work must install sustainable roof systems, either solar photovoltaic (PV) panels or green roofs. Each approach has its own set of resiliency benefits.
Solar PV panels have an obvious resiliency benefit: they provide energy. Energy from solar is particularly beneficial when the city’s electric grid is strained during times of peak demand, though they generally cannot provide energy during a blackout. For added resiliency benefits, solar PV panels can be linked in a localized microgrid, allowing them to operate autonomously when blackouts impact the electric grid at large. The five boroughs currently play host to several pilot microgrid projects, one of the more notable of which is located at Marcus Garvey Village in Brownsville. As more solar panels are installed across the city, particularly when their impact is amplified as part of a microgrid, solar energy serves to further enhance resiliency in the face of extreme weather events.
Green roof systems provide less obvious but no less substantial benefits. Temperatures in urban areas can be as much as 20 degrees warmer than their non-urban surroundings due to the urban heat island (UHI) effect. UHI is in large part driven by dark surfaces with substantial thermal bulk – like asphalt and concrete – absorbing heat that would be reflected back into the atmosphere in less urban locales.
According to the EPA, green roofs can be as much as 40 degrees cooler than their surroundings, as they provide shade and cool the air through evapotranspiration. As green roof systems become increasingly common throughout the five boroughs under the Climate Mobilization Act’s green roof mandate, they promise to have a cooling effect on both individual buildings and communities.
Green roofs are also beneficial for flood mitigation. The same asphalt and concrete surfaces that contribute to UHI also prevent water from penetrating the ground. With nowhere to go, heavy rains – now more frequent, thanks to climate change – lead to flooding. Just this past summer, New York City experienced multiple bouts of significant flooding following heavy rains. Green roofs can help prevent flooding, as stormwater penetrates soil rather than flowing to the street as runoff. Installed at scale across the five boroughs, these systems have a crucial role to play in mitigating rain-induced flooding.
Strengthening Our Communities
Enhancing New York City’s resiliency in an unpredictable 21st century climate must be a community effort. Protecting New Yorkers from the worst impacts of climate change requires large-scale, capital-intensive projects alongside small-scale, building-level resiliency upgrades. While individual building operators cannot singlehandedly stop climate change, they can design their buildings to withstand it.