NYC Apartment Combination: Who Handles the Board, DOB, Architect, and Renovation?

An NYC apartment combination is not just opening a wall between two adjacent units. It is a full planning and renovation process that can involve building approval, an outside architect, DOB filings where required, and a construction plan that makes two separate apartments work as one home.

At a glance

• Start with the combined-home plan — The connecting wall matters, but so do layout, building rules, drawings, permits, and construction logistics.
• Review your building’s process early — Co-op and condo requirements can shape the submission package, work rules, protection plan, and sequence.
• Keep architect and renovation work connected — MyHome coordinates the outside architect who prepares drawings and pulls city permits where required.
• Separate construction from legal ownership questions — A condo renovation may involve different considerations from a legal unit or tax-lot merger.
• Choose one team to coordinate the process — MyHome handles building approvals and city/DOB dealings while guiding the renovation from planning through construction.

For homeowners in Manhattan and Brooklyn, the practical question is usually not, “Can someone remove this wall?” It is, “Who handles the board, the architect, DOB filings, and the renovation so I am not coordinating everyone myself?”

That question should be answered before demolition is discussed.

An NYC Apartment Combination Has Four Separate Workstreams

Short answer: An apartment combination usually involves physical feasibility, building approval, city filings where required, and—when you own condos—separate legal or tax-lot questions. The workstreams connect, but they are not the same process.

The connecting wall gets most of the attention. But a well-planned combination starts with the bigger picture: how the units are laid out today, how you want to use the finished home, what the building allows, and which approvals or filings may be needed before work starts.

Physical feasibility: Can the units work as one home?

The first question is not simply, “Can this wall come out?” It is, “Can these apartments become one practical home?”

That means looking at the intended opening, the route between the units, and how the existing rooms will work after the combination. Two kitchens, separate entry areas, mismatched flooring, awkward hallways, and disconnected electrical or plumbing layouts can all affect the renovation scope.

Whether a particular wall is structural, and what professional review it requires, depends on the building and existing conditions. The NYC Department of Buildings’ alteration-project guidance explains that alteration requirements vary by the type and scope of proposed work.

For many owners, the goal is not just more square footage. It is one home with a clear living area, bedrooms where they make sense, useful storage, and finishes that do not make the former unit line feel obvious.

Building approval: What the co-op or condo needs to review

Your co-op or condo has its own renovation process. Before work begins, the building may require an alteration agreement, drawings, insurance documents, contractor information, work schedules, deposits, and other project materials based on its policies. MyHome’s guide to NYC co-op and condo alteration agreements explains why these requirements need to be reviewed before work is scheduled.

This is not paperwork to deal with after plans are set. Your building’s requirements can shape access, elevator use, site protection, approved work hours, and construction sequencing.

MyHome takes responsibility for building approvals and city/DOB dealings so clients do not have to act as the go-between among the building, architect, and renovation team. MyHome has never been turned down by a residential co-op or condo building. That is a 25-year track record—not a guarantee that any individual board will approve a future renovation.

City filings and permits: What the outside architect handles

MyHome does not employ architects in-house. When a combination requires architectural drawings and city permit filings, MyHome coordinates an outside architect who prepares the required work and pulls city permits. MyHome remains involved throughout so the drawings, building package, and construction scope stay aligned.

Building approval and DOB approval are separate processes. A building may have its own alteration requirements, while the city may require filings or permits based on the work proposed. The NYC DOB alteration-project guidance covers city approval and permit requirements; your managing agent can explain the building’s separate submission process.

The right filing path is not something to assume based on another apartment’s project. It depends on the work, the existing conditions, and the professionals reviewing it.

Condo tax-lot questions: A separate issue from construction

For condo owners, physically connecting two units can raise a separate question: will the units remain separately owned and taxed, or is a legal ownership or tax-lot change under consideration?

[CITATION-NEEDED-VERIFY: A physical combination of adjacent NYC condo units may be distinct from a legal unit merger or tax-lot merger.]

Questions involving ownership records, taxes, common charges, financing, declaration amendments, and resale should be reviewed with your attorney, tax adviser, lender, and other appropriate professionals. [CITATION-NEEDED-VERIFY: NYC condo unit combinations can involve legal, tax, financing, declaration, common-charge, and resale considerations.]

MyHome coordinates the renovation side. Legal and tax decisions remain with you and your advisers.

Who Handles What During an NYC Apartment Combination?

Short answer: MyHome coordinates the renovation, building approvals, and outside-architect relationship. The outside architect prepares drawings and pulls city permits where required. The building reviews its own package. The homeowner makes the ownership, legal, financial, and design decisions that only an owner can make.

A combined-unit renovation has several parties. That should not mean you become the project manager.

What MyHome coordinates

MyHome starts by helping you define the renovation goal and the scope of combining the apartments. That includes the new layout, finish continuity, construction logistics, and the building’s renovation process.

MyHome then coordinates the outside architect when drawings or city permits are required, stays involved in the approval process, and takes responsibility for building and city/DOB dealings connected to the renovation.

The MyHome handoff is straightforward:

1. You start with a Renovation Expert.
2. You work with a Designer on the project’s layout, selections, and design direction.
3. A Project Manager joins at the confirmation/kickoff meeting and leads the project from that point.

That structure matters on a combination project. Someone needs to keep the whole renovation in view—not just the connecting opening.

What the outside architect handles

The outside architect prepares architectural drawings and pulls city permits when required. Their role is to translate the renovation plan into the documents and filings needed for the project.

MyHome coordinates with the architect throughout the process. That keeps the design and filing work connected to the approved construction scope, without suggesting that MyHome is an architectural practice.

What the building, managing agent, and board handle

The building administers its own alteration process. That may include submission review, work rules, approved construction hours, access procedures, insurance standards, and site-protection expectations. These are building-specific requirements, which is why reviewing the co-op and condo approval process early is important.

A board or managing agent is not simply reviewing a drawing. The submission has to fit the building’s process. It is better to understand those requirements early than to rework plans after the fact.

What remains the homeowner’s responsibility

Even when MyHome coordinates the renovation, some responsibilities remain with the owner. You may need to sign building documents, provide requested ownership or financial information, make design decisions, and work with your attorney or tax adviser on condo legal and tax matters.

You also make the biggest decisions: whether to buy the second apartment, what matters most in the combined home, and what level of renovation supports that goal.

The Right Sequence for an NYC Apartment Combination

Short answer: Start with feasibility and building requirements, coordinate the outside architect before required filings, secure approvals, confirm the renovation scope, then move into kickoff and construction. Starting with demolition creates avoidable risk.

The order matters. A combination project is easier to manage when approvals and scope come first—not when construction is rushed because the second unit is already next door.

Step 1: Start before finalizing plans—or before buying the second unit

If you are still considering the purchase, this is the time to discuss what the combined home needs to become. You do not need every finish selected. But you should understand the renovation implications before assuming the apartments can be joined exactly as imagined.

Bring forward the questions that affect the project most: where the connection would go, how the two layouts would work together, whether one kitchen may be removed or redesigned, and whether bathrooms, bedrooms, or living areas need to change.

Step 2: Review the building’s alteration-agreement path

The building’s requirements should be part of planning from the start. An alteration agreement can affect the documents you need and how the work will be performed.

For more on this stage, read what an NYC alteration agreement includes. It is also helpful to understand how co-op and condo board approvals work before plans are submitted.

Step 3: Coordinate the outside architect and required review

Once the scope is taking shape, MyHome coordinates the outside architect needed for the project. The architect prepares drawings and handles city permit filings where required.

Not every combination follows the same technical path. The proposed work, the building, and existing conditions all matter. The NYC DOB’s alteration-project guidance reflects that approvals and permits are tied to the nature and scope of the work.

Step 4: Submit for building review and complete DOB filings where required

The building submission and DOB filing process should stay connected to the renovation plan. Questions from the managing agent, board, or city process need to be addressed without losing sight of what is actually being built.

For more context, see MyHome’s guide to DOB NOW filings for NYC renovations.

Step 5: Confirm the scope before construction begins

Before construction, you should receive a written proposal outlining the recommended scope of work and pricing. On a combination renovation, known work may include permits, riser or pipe work, and subflooring, depending on the apartment and scope.

MyHome’s approach is transparent upfront. If an unforeseen condition appears, work stops. The client sees the issue, receives the reason and exact price, and approves it in writing before work proceeds. The process is not replace first, bill later.

Step 6: Move into kickoff, building logistics, and construction

At the confirmation/kickoff meeting, the Project Manager enters and leads the project from there. The team coordinates building access, protection, deliveries, sequencing, and the renovation work itself.

What Combining the Apartments Means Beyond the Connecting Wall

Short answer: The opening between units is usually only one part of the work. Most owners also need to resolve circulation, duplicate spaces, systems, finishes, and building logistics so the final home feels cohesive.

A new opening can make the two apartments accessible to each other. It does not automatically make them feel like one residence.

You may decide to keep both kitchens, convert one kitchen area to another use, relocate living functions, create a larger primary suite, improve storage, or redesign an entry sequence that no longer works. Lighting, flooring, cabinetry, plumbing, electrical planning, and paint all need to be considered across both units.

Construction logistics matter too. Buildings may have specific work-hour restrictions, elevator reservation rules, access procedures, and site-protection requirements. Those details should be confirmed through the building’s alteration process before construction begins.

That is why an NYC apartment combination often becomes a full renovation rather than a limited wall-removal project. If you are planning a Manhattan project, explore MyHome’s full apartment renovation services in Manhattan. Brooklyn owners can learn more about full home renovation services in Brooklyn.

Co-op vs. Condo Apartment Combinations: What Changes?

Short answer: Both co-ops and condos have renovation approval processes. Condo owners may also need separate advice about legal ownership and tax-lot questions. Construction approval is not necessarily the same as a legal merger.

Co-op owners should expect a building-specific alteration review process. The exact documents, requirements, and review path depend on the building.

Condo owners also need to follow their building’s renovation procedures. But if the long-term plan includes legally consolidating the units rather than simply renovating them to work together, there may be separate legal, tax, ownership, or lender issues to address. [CITATION-NEEDED-VERIFY: NYC condo owners considering unit consolidation may need to review separate legal, tax, ownership, and lender requirements.]

The practical takeaway is simple: keep the renovation conversation and the legal/tax conversation connected, but do not assume they are handled by the same professional.

Questions to Ask Before Hiring an Apartment Combination Contractor

Short answer: Ask who owns coordination, who handles the architect relationship and building submission, who leads after approval, and how unexpected conditions are priced. Clear answers now prevent confusion once work is underway.

Ask these questions before you commit:

• Who coordinates the outside architect and required permit process?
• Who gathers and follows up on the building’s alteration requirements?
• Who is my main point of contact after the project is approved?
• When does the Project Manager enter the process?
• How do you handle unexpected conditions behind walls or under floors?
• How will the two apartments be planned as one finished home?
• What will I still need to sign, decide, or provide?

You should be able to see the path from the first conversation to construction—not just hear that a company “handles everything.”

Start With a Feasibility Conversation, Not a Demolition Plan

Short answer: Before planning a wall opening, clarify the full combination scope, your building’s approval path, and the roles of MyHome, the outside architect, and your own legal advisers.

MyHome has spent 25 years helping Manhattan and Brooklyn homeowners plan and deliver apartment renovations. For apartment combinations, MyHome coordinates the outside architect who pulls city permits where required, takes responsibility for building approvals and city/DOB dealings, and stays involved through the renovation.

The goal is not to make a complex project sound simple. It is to give you a renovation team that knows who needs to do what—and when. A 10-year written warranty also provides clear, written protection after the renovation is complete.

If you are considering combining two adjacent apartments, book a free renovation consultation with MyHome Renovation Experts NYC.