New York City has built up and built out, but it has never purposefully built small.

Recent zoning changes created an opportunity for homeowners to build accessory dwelling units, small homes within existing properties that can provide additional living space, rental income, or housing for family members. Yet the regulatory landscape surrounding ADUs is complex. Zoning rules, building codes, fire separation, ceiling heights, flood zones, and financing requirements form a tangle of information that is difficult for most homeowners to understand.

WXY led an effort with the Office of the Mayor, the New York Department of Buildings, and the New York Department of Housing Preservation and Development to make this new housing opportunity accessible. The result was a coordinated platform and website that brings together design guidance, regulatory clarity, and digital tools.

Across New York City, ADUs can now take several forms depending on a property’s conditions. Backyard cottages, basement apartments, attic conversions, and small additions respond to different lot configurations and housing needs. Introducing these typologies early helps homeowners understand the possibilities within their own property before confronting the complexities of regulation and construction.

WXY approached the program by putting homeowners first.

Appendix U of the NYC Building Code introduced the regulatory framework for ADUs, but the language of code can be difficult for non-specialists to interpret. Our work translated these requirements into clear explanations while preserving their technical accuracy.

To make the path forward understandable, the platform organizes the journey into steps that guide homeowners from conception to construction. Each step introduces tools and resources designed to help homeowners make informed decisions.

At the same time, the platform was shaped through user testing and community engagement. Representative homeowners tested the tools and navigation to ensure the platform responded to real questions and concerns. This process reflects WXY’s broader commitment to human-centered design, where the real needs of the people impacted shape the information, digital tools, and architecture we create.

The first step we developed was a way for homeowners to understand whether an ADU is possible on a particular property. The Eligibility Lookup Tool allows homeowners to search their address and see what type of ADU may be permitted. By translating zoning rules and building code requirements into an intuitive interface, the tool offers an immediate sense of feasibility before homeowners commit time or resources.

Once homeowners understand their eligibility, the platform allows them to explore how an ADU might fit their property. An interactive map displays the layout of a homeowner’s parcel and allows users to test-fit designs from the pre-approved plan library within the constraints of their lot. This tool helps translate setback rules, access requirements, and building envelopes into a spatial understanding of what is possible.

For some homeowners, an ADU provides housing for family members. For others, it offers a path to supplemental income or long-term property value. The platform encourages users to clarify their goals early, since each objective shapes design choices, financing strategies, and construction timelines.

The Pre-Approved Plan Library offers a running start for detached ADU projects. It hosts DOB-approved designs complete with floor plans, square footage, materials, and estimated costs. These plans demonstrate how thoughtful architecture and regulatory compliance can reinforce one another.

Alongside design guidance, the Budgeting Tool provides a grounded understanding of construction costs, financing options, and potential rental income. By presenting financial realities clearly, the tool helps homeowners evaluate whether a project aligns with their goals and resources.

The Guidebook provides a deeper context that ties the platform together. Written in clear language and designed with accessibility and clarity top of mind, it explains zoning rules, building code requirements, permitting processes, and construction considerations across New York City.

Construction is often the most intimidating stage for homeowners. The guidebook prepares users for this phase by outlining the steps required to assemble a project team, coordinate permitting, and oversee construction from foundation to completion. It also explains the requirements that must be met before occupancy, including final approvals, inspections, and documentation needed to ensure that the unit is safe and legally habitable.

Throughout the web platform and guidebook, we introduce environmentally responsible approaches to ADU construction. Efficient building systems, durable materials, and climate-conscious design strategies help ensure that these small homes contribute to a more sustainable housing stock for the city.

The NYC ADU for You program reframes housing reform as a challenge that can be partially solved by thoughtful design and engagement.

By combining policy translation, architecture, digital tools, and community engagement, the platform WXY developed reduces uncertainty and shortens the distance between intention and action. For homeowners, the process becomes navigable. For the City, the policy goals of Appendix U become measurable for housing production.

At a time when cities are searching for scalable housing solutions, this work demonstrates that architecture does not only produce buildings. It can also design the systems that make them possible.