Local and national regulations related to housing in flood zones do not address the conditions of a dense urban place like New York City.<

The Post-Sandy Housing Working Group’s focus was to learn what happened during Sandy and why, and to use these lessons to:<

  • Encourage the development of new strategies to address the evacuation and temporary rehousing of those displaced by future disasters;
  • Make existing housing stock more resilient;
  • Ensure that future housing is built in a way that is safe, resilient, and beautiful.

An analysis by NYU’s Furman Center for Real Estate and Urban Policy and the NYC Department of City Planning revealed a few clear patterns about what worked and what did not work in residential construction.<

Buildings built to modern floodproofing standards fared much better structurally than older buildings. 84% of the buildings in the flood zones were built before 1983, when New York City incorporated floodproofing requirements into the Building Code. 94% of the red-tagged buildings (i.e., those requiring repair before occupants can re-enter) were built before this date. 98% of the destroyed buildings were built before this date. Retrofitting existing housing stock and rebuilding new housing to higher, more stringent standards will require changes to the multilayered regulatory climate currently governing floodproofing issues. Also needed are creative approaches to ensuring that these changes result in safer, more resilient, and beautiful buildings and communities. Multi-family buildings fared much better than one- and two-family buildings. 90% of the red-tagged buildings were one- and two-family buildings, even though they made up less than 30% of the floor area of all red-tagged buildings. Local and national regulations related to the design and construction of housing in flood zones have yet to take into account issues related to floodproofing in the country’s densest urban environments. As building owners have  moved on from immediate post-disaster recovery efforts and take the next steps to make their buildings more resilient in a post-Sandy world, the need for more attention to the future floodproofing needs of multifamily buildings has become clear.<

The work by CHPC, NYSAFAH, and AIANY after Sandy revealed several issues related to displacement and rebuilding. These include: the need for organizational structures for non-profit housing providers to work together after such disasters; the potential for alternate solutions to the trailers and other temporary housing deployed after Sandy; and the need for protections that allow design professionals to play a constructive role in addressing emergency situations (the Good Samaritan Law). CHPC has recently employed a full-time Fellow who has established Zone A New York, Inc., a non-profit organization working on the ground building capacity and charged with addressing many of the key priority items outlined by the Housing Working Group.<

Five months after Sandy, the short term has already come and gone. The Housing Working Group accordingly focused on mid- and long-term recommendations, particularly the most important needs and priorities. We identified six priority areas for the design community’s attention.<

Post-disaster measures to house people displaced from their homes NYSAFAH’s experience coordinating the use of vacant apartments for temporary housing for people displaced by Sandy showed that there are alternatives to mobile homes or other temporary housing. However, the currently low vacancy rate and issues of supply vs. demand complicated this. Learning from Sandy, they recommended the following ideas to prepare for future disasters:<

  • Develop an outreach strategy to communicate with building owners
  • on available vacant units;
  • Develop a centralized intake process for applications and referrals for displaced households;
  • Identify waivers necessary for
  • the rehousing process;
  • Identify and craft a model third-party lease agreement for households seeking temporary housing;
  • Adopt an expedited qualifying process for displaced households applying
  • for permanent affordable housing;
  • Advocate for allocation of disaster-related Section 8 vouchers for households below 30% AMI.

As for the regulatory requirements for design and construction of buildings, many of these are affected by overlapping regulations that make sense in normal times, but are not set up to deal with issues of housing after disasters such as Sandy.<

Capacity Building

The period after Sandy revealed an absence of organizational structures to support the efforts of non-profit housing providers trying to work together. Two key priority areas were identified:<

  • Establishing programs in post-disaster training for non-profit leadership;
  • Establishing a new citywide non-profit organization charged with addressing the needs of residents living in Zones A and V neighborhoods.

Changes to the Existing Patchwork Quilt of Floodproofing Regulations

The NYC Zoning Resolution, NYC Building Code, FEMA design standards, and federal accessibility guidelines all address floodproofing issues to some extent. However, as may be expected, these regulations are not fully coordinated. Through a multidisciplinary Post-Sandy Housing Charrette, the Working Group generated a series of recommendations for addressing gaps both within and between each of the set regulations pertaining to floodproofing.<

Retrofitting Existing Multi-Unit Housing Stock<

New York is a growing city with limited land. In most cases, multi-family buildings in the flood zone were heavily damaged, but by and large remain structurally sound. These buildings, particularly those owned by the New York City Housing Authority (NYCHA), represent a significant portion of the City’s low-income housing inventory and would be exceedingly costly to replace. With strategic modifications, the useful life of most of this stock can be extended well into the future.<

Create a body of literature to guide the future floodproofing needs of multi-family buildings, available in various languages
Local and national regulations related to the design and construction of housing in flood zones have not fully taken into account what is required for floodproofing in dense urban environments.<

Study the Broader Planning Implications <

The specific focus of the Housing Working Group was the scale of the individual residential building. During the course of our work, however, many questions regarding larger planning and policy decisions were raised:<

Given the likelihood of rising sea levels, for instance, should building codes require that buildings in the City’s coastal zones be designed for higher flood levels than currently projected?<

Should recent downzonings in coastal areas be reexamined to understand whether allowing exceptions for multifamily housing could increase the resiliency of these communities?<

How can other equally threatening factors that may emerge from the next storm, including flooding resulting from intense rainfall and wind, be addressed?<

It is the hope of the Housing Working Group that its work and recommendations will be considered and used by the responsible agencies. It should be stressed that the conclusions and recommendations in this report do not represent the policies or recommendations of any one of these individual groups or agencies.<

Local and national regulations governing the design and construction of housing in flood zones have not fully taken into account what is required for floodproofing in the densest urban environment in the country. The New York City Zoning Resolution, the New York City Building Code, FEMA design standards, and federal ADA guidelines all address flooding issues to some degree. However, these regulations are not fully coordinated, so a requirement stated in one may be in conflict with another. As a result of the multidisciplinary charrette held in February 2013, the Working Group generated several recommendations, which will need to be verified and modified based on specific neighborhood characters, building types, and site conditions.<

NYC Building Code<

  • Permit handicapped lifts in flood zones;
  • Wet floodproofed buildings should have an emergency exit at the first floor above flood elevation;
  • As an alternative to floodproofing individual buildings, allow block-wide or neighborhood-wide floodproofing.

NYC Zoning Resolution<

  • Once a Design Flood Elevation of three feet is reached in a residential building, its first residential floor should be allowed to be raised to ten feet, without maximum building height penalty, so as to create a full-height floor at grade. This would allow a full-height lobby and elevator, providing an accessible common entrance
  • at grade for all residents, and use for storage or parking or community space.
  • In an existing building, if the ground floor cannot be used, expansion should be permitted horizontally or vertically, where possible, to make up for lost habitable space.
  • Make alignment provisions in contextual districts more flexible. In some cases they currently prevent setting a building far enough from the property line to have a ramp composed of a flood-dampening landscape or permeable paving in front of the building.
  • Where a building may have to be set back from the street line to accommodate flood zone-related steps and ramps, rear yard requirements should be reduced.
  • Study of more flexible zoning envelopes should be undertaken so that moving more of the mechanical spaces above the flood zone is encouraged.
  • Allow electric rooms to be floor-area deductible.
  • Permit mechanical equipment in rear yards above flood elevation.
  • Rezoning should allow for greater density in return for greater landscape buffer zones in the flood zone.
  • Stairs with natural light should be deductible, as is already encouraged in quality housing zoning for corridors in buildings in contextual districts.


  • Dry floodproofing of lobbies, currently permitted for mixed-use residential only, should be allowed for all multi-family buildings.
  • Evacuation in place—FEMA’s objective is to evacuate flood areas before floods occur, and to minimize the risks, especially to first responders. This may not always be possible in a dense urban environment such as New York. It is important in a flood event that those who do not follow government orders, for whatever reason, have a way to get out of their buildings and to safety during a flood.

Accessibility Regulations<

  • Entrances and ramps that lead to the interior of the primary lobby should be permitted.

Changes in National Flood Insurance Policies

The National Flood Insurance Program (NFIP) was recently changed so that rates for buildings that meet floodproofing requirements will be significantly lower than rates for buildings that do not. This will mean that many building owners who cannot afford to meet the requirements will not be able to afford flood insurance. This is particularly true of one- and two-family and attached row houses within the flood zones, where modifying the buildings may be as costly as building new. Therefore, many buildings will not get insurance and cannot be upgraded to current floodproofing standards. This creates potential risks and costs for the City and other levels of government when the next catastrophic storm hits.<

For existing buildings in the new or expanded flood zones, particularly one- and two-family detached and attached homes, renewing insurance will require much more robust floodproofing measures. These measures are likely to be costly. Efforts should be made to develop more affordable floodproofing options such as active barrier installations. Techniques to collectively fund and maintain such systems, which would decrease costs to individual homeowners, are used successfully in places like Prague in the Czech Republic and should be studied.<

Other Issues<

  • Illegal basement apartments in buildings in the flood zone. While there is no definitive count of how many exist, there are vast numbers of such units that cannot be re-inhabited. This will be a hardship for displaced renters and owners who are dependent on this income.
  • Dealing with the regulatory impediments to short-term rental of vacant housing units (see Appendix).
  • A Good Samaritan law for design professionals.

The Broader Context

Although the charge of the Working Group was to focus on individual residential buildings, many questions regarding larger planning and policy decisions were raised. Should the building code require that buildings in the City’s coastal zones be designed for higher flood levels than currently projected? Or, if possible, should we find ways to return vacant or irrevocably damaged sites to soft-edge conditions (a program initiated by New York State on Staten Island)? Newly published projections on sea-level rise should be closely studied in conjunction with the now updated FEMA flood maps. Regulations could, for instance, permit or encourage floodproofing in the 500-year flood zone.<

Over the last twenty years, many low-density areas of the City have been downzoned. For a variety of reasons described elsewhere in this chapter, multifamily buildings are more resilient and easier to retrofit to incorporate floodproof features. In addition, efficiencies of scale allow emergency systems that facilitate faster reoccupations of multifamily buildings in flood areas. In coastal areas, these downzoned areas should be reexamined.<


FEMA Multifamily Manual<

Existing FEMA literature had tremendous value in getting the Working Group up to speed. However, regarding residential construction, the current FEMA and National Flood Insurance Program (NFIP) literature are largely focused on one- and two-family housing and fail to cover many issues related to multifamily housing. The Housing Working Group has identified several areas where we believe that we can be of help to FEMA in outlining, and perhaps helping to author, a FEMA multifamily design guide.<

Design of Areas Below Base Flood Elevations<

Careful design of spaces below the base flood elevation (BFE) is important for all types of housing. It would be expected that only water- and mold-resistant materials be used below the BFE no matter the housing type. Multifamily housing structures, however, often differ from one- and two-family buildings. Based on height, longevity, and combustibility concerns, multifamily housing typically incorporates robust materials such as masonry and concrete. During Sandy, it became clear that these structures performed better than the wood framing typical of one- and two-family homes.<

When flood elevations rise, minimum required elevations for residential spaces rise, and with these increased elevations come the vertical conveyances needed to get people to those elevations. In one- and two- family housing, where accessibility rules do not apply or are often less stringent, stairs can be used for elevations too high for ramps. Because of a multitude of accessibility regulations, multifamily housing typically must incorporate ramps, elevators, and lifts. Zoning regulations should be adjusted to recognize the amount of space these features occupy. For instance, as BFEs exceed three feet above grade, we recommend that first-floor residential be permitted to be raised to ten feet without maximum building height penalty, so that a full-height lobby can be accessed at grade and dry- or wet-floodproofed as required for common access to an elevator.<

On-Site Evacuation and Areas of Refuge

When it comes to occupants’ life safety at the time of an impending storm, evacuation is the best policy, regardless of housing type. Yet several external factors combine to make evacuation from multifamily housing more difficult, placing rapid post-storm re-occupation of homes more critical. Multifamily housing often occurs in dense, urban communities that are transit-dependent, like New York City. But as Sandy has shown, mass transportation may be affected by or limited during an emergency, and mass evacuations can lead to congestion and a reduction in mobility.<

Two types of specialized multifamily housing present particular challenges to evacuation, and underscore the need to address the issue of those who may not be able to leave their homes. First, low-income rental buildings, where residents may not possess cars, or the resources to move to temporary housing. Secondly, supportive and senior housing where residents may be attached to their permanent homes because of medical or disability concerns and cannot easily transport themselves elsewhere. To address these situations, the Working Group recommends identifying a safe room (most likely, a community room) that can be used for congregating, roll call, and rescue during emergency conditions.<

Building Systems <

Multifamily housing should be engineered with building systems that protect against building shutdowns during emergencies and ensure a quick return to normal or standby functions post-event. One example is reliance in municipal utility-provided electricity. One- and two-family home operators may opt to partially power their homes with oil-fueled generators. This is not an option for multifamily housing.<

Mid-rise multifamily housing is, however, a good candidate for the use of emergency generators wired to a transfer switch with emergency power circuits. In high-rise construction, in fact, the Building Code requires this. In New York City, more and more buildings are installing city-piped natural gas-fueled generators; this trend may have broader policy implications given the fact that the City gas supply has not been interrupted during major storms.<

We believe there are additional opportunities for emergency generators to be used for cogeneration. Cogeneration, in which heat entropy generated in the process of creating electric power is captured for heating and domestic hot water, is most efficient in multifamily housing, particularly in projects of 100 or more units. With cogeneration’s transfer switch and emergency circuitry also comes the opportunity to wire renewable power sources, such as photovoltaic panels and wind turbines, into the building for safe use during power outages. This would allow fire pumps, elevators, emergency lighting, refrigerators, and even a convenience outlet in each apartment to remain operational. It would also provide for heat and hot water to remain available via cogeneration. Finally, high-performance building envelopes, which are increasingly required and more likely to be financed for multifamily housing projects, could contribute to the efficiency of backup systems.<

Best Practices

The Housing Working Group contacted AIA, ASLA, and APA chapters around the country, asking for best practices in floodproof design. We developed a form to collect information in an organized and comparative format listing project location, housing type, flood elevation data, design strategies, flood-based regulatory actions, lessons learned/recommendations, and project graphics. All of these documents are catalogued and appear in the online appendix. These materials include methods for installing removable dry-flood barriers to existing buildings as used in Coney Island, and the Pontilly Neighborhoods Association’s work in New Orleans, where landscape architects used flood mitigation techniques to absorb and re-channel floodwaters. Future research will collect examples from overseas as well as other cities in the United States.<

Below are additional reports and appendices by individual working groups, individuals and organizations who are part of the Post-Sandy team.  They are posted as submitted by the authors and have not undergone review or rewriting by the editorial team.<

Housing Charrette<

NYUs Furman Center SandyFactBrief_Feb28<

NYSAFAH Disaster Rehousing Recommendations<

CHPC Sandy Memo<

Best Practice Survey Pontilly Flood Design<

Best Practice Photos Pontilly<

Wids DeLaCour, AIA
Mark Ginsberg, FAIA, LEED AP
Adam Watson, AIA, LEED AP<

Anthony G. Piscopia, RA
Alex Alaimo, AIAS
Ralph P. Albanese, AIA
Venesa Alicea, AIA, LEED AP BD+C
Domenico Antonelli, PE
Illya Azaroff, AIA
Alison Badgett
Charlotte Barrows
Cynthia Barton
Christina Battiston, Assoc. AIA
Carmi Bee, FAIA
Vicki Been
Ed Bosco, PE, LEED AP
Timothy Boyland AIA
Clark Brewer
Gary Brown
Lance Jay Brown, FAIA
David Businelli, AIA
Sylvia Cardozo
Andres Carter
Margaret Castillo, AIA, LEED AP
Taewook Cha, RLA, ASLA, LEED AP BD+C
Susan Chin, FAIA, 2013–2014 AIA Vice President-Elect
James Colgate, RA, Esq.
Harold Colon
Gonzalo V. Cruz, ASLA
Larry Dennedy
Eugenia Digirolamo
Gene Eng, PE
Eric Fang, AIA, AICP, LEED
John Ferrante, PE, LSRP
Donald Friedman, PE
Deborah Gans, AIA
Alexandra Hanson
Dakota Hendon
Christopher S. Holme, AICP
Ernest Hutton, Jr., Assoc. AIA, FAICP
Matt Jackson
Marcie Kesner, AICP
Andrew Knox, AIA
Marcelo Kohan, AIA
Cory Kohut
Alan Krischanovich
Dikshat Kumar
John Lee
Nick Lembo
Trent Lethco
David Levine, AIA, LEED AP BD+C
Mark Levine, AIA, LEED AP
Theodore Liebman, FAIA
Michael Lohr, Assoc. AIA
Jonathan Marvel, FAIA
James McCullar, FAIA
Andrew McNamara, CEM, LEED AP
Timothy Moore, PE, LEED AP
Fred Mosher, Jr., AIA
Leigh Overland, AIA, NCARB
Thaddeus Pawlowski
Sophie Pennetier
Jerilyn Perine
Jeffrey Poor, RLA, ASLA, LEED AP
Daniel Powell
Tom Raihl, PE
Anushree Raina
Sean Rasmussen, Assoc. AIA
James Rausse, AICP
Adam Reeder, PE, CFM
Lyn Rice, AIA, LEED AP
William Rockwell
Nicolas Ronderos
Mary Elizabeth Rusz, AIA
Frank Schimenti
Fred Schwartz, FAIA
Franz Seborga, PE
Martha Sickles, LEED AP, AICP
Varanesh Singh
William Stein, FAIA
Abdul Tabbara, PE
Kyle Twitchell, PE
Florin Vasilescu, AIA
Gary Vegliante
Cristian Vimer, PE
Donna Walcavage, FASLA, LEED AP
Jessica Wang
Tom Wargo
Sarah Watson
Lee Weintraub, FASLA
Mary Weselcouch
Tom Wright
Steven Zirinsky, AIA<