New York DOB Approves 90-Story Underground Earthscraper

The article reports that New York City’s Department of Buildings has approved plans for what officials call the city’s first “earthscraper.” This 90‑story structure would be built below street level to create housing while keeping skyline views intact.

The project is still mostly conceptual. No site, developer, timeline, or engineering drawings were disclosed, and a full regulatory and environmental review is still required.

Earthscraper supporters describe a dense, below‑grade form that could increase housing without changing historic street fronts. In New York City, where regulations protect views and streetscapes, digging down instead of building up is a new approach to increasing density.

The Department of Buildings framed the approval as a first step toward possible subterranean towers across the boroughs. However, it provided few details about site location, timeline, or technical plans.

The concept is similar to projects like the InterContinental Shanghai Wonderland, showing that large‑scale below‑grade construction is possible. Still, New York’s climate, soil, and urban utilities present unique challenges that go beyond typical below‑grade work.

Political momentum and high‑level approvals can move faster than engineering readiness. A fully subterranean 90‑story megastructure would be a first for New York City, even though similar projects exist elsewhere.

The proposal reflects a broader trend toward high‑density housing that reduces surface impact and protects historic areas. Practical development will require advanced engineering, strong waterproofing and ventilation systems, and careful risk management.

Engineering and design considerations

Building a deep, subterranean megastructure involves challenges in five main areas: groundwater control, waterproofing, ventilation, daylighting, and safe evacuation. These are important issues for engineers and designers, even before a site is chosen.

Groundwater management needs advanced systems to handle changing water pressures and possible leaks. Waterproofing must be reliable and long-lasting, with plans for monitoring and repair.

Ventilation is a major concern, as fresh air and climate control are harder to maintain deep underground. Daylighting requires creative solutions to bring natural or artificial light into deep spaces for livable environments.

Emergency exits and life safety systems must be redundant and able to function in emergencies. These systems are especially important in densely populated urban areas.

• Groundwater control: robust, site‑specific dewatering and water management strategies to prevent seepage and undermining of adjacent structures.
• Waterproofing and drainage: layered barriers with monitoring, capable of long‑term performance in a submerged environment.
• Ventilation and indoor air quality: advanced MEP systems to ensure fresh air delivery and climate control, with redundancy.
• Daylighting and human factors: optical design approaches to bring light into deep spaces and create habitable environments.
• Evacuation and life safety: comprehensive egress plans and backup systems for emergencies, including smoke control and refuge spaces.
• Structural integration: a foundation and overall structural system engineered to accommodate significant settlements, loads, and soil conditions.

Other challenges include excavation logistics in a crowded city, such as soil removal, rising costs, construction disruption, traffic management, and utility impacts. Careful planning of water, air, and energy systems is essential before starting any large underground project.

Regulatory pathway and community implications

Even with support from the Department of Buildings, the earthscraper proposal must go through a long regulatory process. New York City’s environmental review, under the City Environmental Quality Review (CEQR) framework and possibly an Environmental Impact Statement (EIS), will study environmental, traffic, noise, and community effects.

Land‑use reviews will involve community boards and votes from City Planning and the City Council. The DOB’s approval is just one step in a longer process managed through DOB NOW and other city procedures.

For neighborhoods, major below‑grade excavation brings concerns about soil disturbance, groundwater, and impacts on water and sewer systems. There will also be temporary disruptions to street life and traffic.

Practitioners should expect strong community engagement, detailed environmental studies for each site, and clear explanations of how underground construction will work with existing infrastructure and utilities.

What happens next and what practitioners should monitor

• Site selection and feasibility studies are the first visible steps to turn a concept into a project.
• Comprehensive environmental review includes CEQR scoping and public comment periods. This may also involve an EIS to address water, air, energy, and noise impacts.
• Coordination among agencies is needed with City Planning and the City Council. Relevant state authorities must also align zoning, financing, and permitting.
• Design readiness and risk management require clear safety, ventilation, emergency evacuation, and life-safety strategies. These strategies must be documented for review.

 
Here is the source article for this story: DOB Approves 90‑Story Underground Earthscraper For New York