Office Renovation Contractor
NYC, Westchester & Nassau County
Licensed general contractor for offices, medical suites and commercial buildouts — including work phased around a business that stays open.
We are a licensed general contractor building out offices across New York City, Westchester, and Nassau County. Most of our office work happens in buildings that never close — a medical practice seeing patients down the hall, a retail floor that has to reopen on a fixed date, apartments occupied above the ceiling we are opening up. The scheduling and the filings are usually harder than the construction.
Below is how the work actually goes: what it costs, what gets filed, what holds permits up, and how we keep a business running through it.
What does an office renovation cost in NYC?
For a white box build-out — an empty shell taken to a finished, occupiable office — we quote $75 to $250 per square foot on most commercial jobs. Cosmetic refreshes on an existing office run well below that. Heavy MEP work, medical or lab requirements, or high-end finishes run well above it. The spread is driven by mechanical scope more than by anything you can see.
Three things move the number more than finish selections do:
| Cost driver | What it actually means |
|---|---|
| Existing conditions | What is behind the wall. On one recent office we had to cut every door down at the bottom to clear new flooring, and repair hinges and locks throughout — none of which appears on a drawing. |
| Mechanical scope | Whether you are reusing the building’s HVAC or bringing in new equipment. Rooftop units currently carry long lead times; on a recent commercial job Carrier quoted 13 to 15 weeks, which set the entire schedule. |
| Building rules | Freight elevator windows, insurance requirements, approved work hours, and whether the building will let you work while occupied. These change the labor cost, not the material cost. |
Do I need a permit to renovate an office in NYC?
Almost always, yes. Any alteration beyond cosmetic work — moving walls, changing egress, touching plumbing, mechanical, or electrical — requires a filing with the NYC Department of Buildings. Painting, carpet, and furniture do not. The distinction is whether you are altering the building, not how much you are spending.
The filing categories changed, and most contractor websites have not caught up. The old BIS classifications people still quote — Alt-1, Alt-2, Alt-3 — no longer describe what you file. In DOB NOW: Build, the current system, there are two:
| What you file now | Former BIS name | When it applies |
|---|---|---|
| Alteration-CO | Alt-1 | Work that changes use, egress, or occupancy — and therefore changes the Certificate of Occupancy |
| Alteration | Alt-2 and Alt-3 | Everything else — interior office work that does not alter the CO |
DOB states this directly in its DOB NOW: Build FAQ: “Alt-2 and Alt-3 in BIS are Alteration in DOB NOW and Alt-1 in BIS is Alteration-CO in DOB NOW.” Most standard office fit-outs are an Alteration. Convert a retail space to offices, or offices to medical, and you are filing an Alteration-CO.
One thing worth knowing before you hire anyone: a contractor cannot file your plans. A New York State Registered Design Professional — a licensed architect or professional engineer — has to. We work off their filed set and pull the contractor permits against it, and we coordinate the expeditor, but the drawings are theirs.
How long does a DOB permit take, and what actually delays it?
Plan approval to permit typically runs several weeks once drawings are approved. But in our experience the plan examiner is rarely the bottleneck. The delays that cost real time are administrative, and they are almost always avoidable.
The most common one is insurance. On a recent Manhattan job our architectural plans were approved on a Monday, and the permit still could not be pulled — our general liability, workers’ compensation, and disability certificates had not been updated with DOB since 2024. We had new certificates filed the next day and the permit issued the following week. Nothing about the project was at fault. The paperwork was stale.
The second is that NYC alteration permits expire fast. That same permit was issued on April 1 and expired May 25 — under eight weeks. It had to be renewed to keep working, and the renewal was itself held up by a workers’ compensation certificate about to lapse. On any job longer than two months, permit renewal is a scheduled task, not an afterthought. We track expiration dates against the construction schedule from day one.
If your contractor cannot tell you the current status of their DOB insurance filings, that is the question to ask before signing.
Can we stay open while the office is renovated?
Usually, yes — and most of our office work is done exactly this way. It requires sequencing the job around your operations rather than around ours, which means phasing the space, containing dust properly, and accepting that the schedule will be longer than an empty-space build.
What that looks like in practice:
- Temporary partitions with zipper doors sealing the work area from occupied space, with negative-air dust control behind them
- Phased hand-backs — on a recent retail and clinic fit-out we contracted two distinct phases with a hard substantial-completion date on the first, so the business could reopen on a known day rather than a hoped-for one
- A punch and testing window built into the schedule between phases, not tacked onto the end
- Coordination with building management on freight access, protection of common areas, and certificates of insurance naming the right parties
One contractual note that saves arguments later: if you change the phasing mid-job, that is a change order. We write it that way up front so the conversation happens before the work does, not after.
What are legal working hours, and when do we need an after-hours variance?
Standard construction hours in New York City are 7:00 a.m. to 6:00 p.m. on weekdays. Any work before 7:00 a.m., after 6:00 p.m., or on a Saturday or Sunday requires an After Hours Variance from DOB. Applications go in at least three business days ahead, and a single permit can cover up to 14 consecutive days.
Full details are on DOB’s After Hours Variances page. Two things to budget for: after-hours labor carries a premium, and buildings often have their own quiet-hours rules that are stricter than the city’s. Check the building’s alteration rules before you assume nights are available.
What if there are apartments above the office?
Mixed-use buildings add a layer. If residential units stay occupied during construction, DOB requires a filed Tenant Protection Plan describing how you will protect them — dust, noise, egress, fire safety, structural work. On a recent ground-floor commercial fit-out, 19 apartments remained occupied above us throughout the job.
A TPP is not paperwork you produce and file away. It comes with an independent inspector and, where structural or mechanical work is involved, special inspections against the filed drawings. Budget for both. They are line items, not overhead.
Does an office renovation trigger ADA or energy code work?
Often, yes, and it surprises people. Altering an existing commercial space can trigger accessibility requirements under the 2010 ADA Standards for Accessible Design — accessible routes, door clearances, restroom configuration, signage, and alarms. NYC layers its own requirements on top, and applies them regardless of building age or landmark status.
Separately, work that touches the building envelope, lighting, or HVAC generally has to demonstrate compliance with the NYC Energy Conservation Code, with progress inspections signed off during construction. Your architect or engineer determines what is triggered. Our job is to build to it and get it inspected without a second trip.
What we handle on an office renovation
We self-perform supervision and run procurement in house, and we coordinate the trades directly rather than through a layer of subcontracted management. On a typical office project that covers:
- Demolition, framing, drywall, and ceilings — hung, ACT, or exposed
- Electrical, lighting, and low-voltage rough-in coordination
- Plumbing and HVAC coordination, including long-lead equipment tracking
- Custom millwork — reception desks, workstations, pantries, storage walls
- Flooring, wall finishes, glazing, and partition systems
- ADA-triggered upgrades and restroom reconfiguration
- Permit coordination with your architect, engineer, and expeditor
- Punch list, closeout documentation, and sign-offs
We work with your architect and designer, or we can recommend one. A significant share of our work comes through the design professionals we have built with before, and we are set up to protect design intent rather than value-engineer it away quietly. More on how we work with designers and architects, and the rest of our construction services.
Where we work
Manhattan, Brooklyn, Queens, and the Bronx; Westchester County; and Nassau County. Our office is in New Rochelle, which puts most of Westchester and lower Fairfield inside an hour and Manhattan inside forty minutes.
We are licensed in all three jurisdictions: NYC DOB General Contractor GC-624413, NYC DCWP Home Improvement Contractor 2101404-DCA, Nassau County H0457670000, and Westchester WC-33735-H21. We carry general liability, workers’ compensation, and disability, and we keep our DOB filings current — which, as noted above, is not a given in this trade.
Frequently asked questions
Who pays for an office build-out, the landlord or the tenant?
It depends on your lease. Many commercial leases include a tenant improvement allowance that the landlord contributes toward the build-out, with the tenant covering the balance. The allowance is negotiable, and it is worth having a contractor price the space before you sign, so you know whether what is being offered actually covers the work.
Can you work within a fixed budget?
Yes. We price from a filed or near-final drawing set and identify where the money is going by division, so if the number comes in high you can see exactly which scope to adjust. We would rather have that conversation during pricing than through change orders later.
Do you handle the permits?
We coordinate them. Your architect or engineer files the drawings — that is a legal requirement in New York — and we work with the expeditor, pull the contractor permits against the approved set, and manage renewals and inspections through closeout.
How long does an office renovation take?
From approved drawings, a straightforward office fit-out is typically a few months of construction; phased work in an occupied space takes longer, and mechanical lead times can extend it further. The honest answer is that permitting and equipment procurement, not construction, usually determine the finish date.
Do we need an engineer as well as an architect?
Frequently. Structural changes, significant mechanical work, and special inspections require a professional engineer. On mixed-use and occupied buildings you may also need a separate tenant protection plan inspector and special inspection agency. We can tell you early which of these your scope will trigger.
Start the conversation
If you have a space and a set of drawings — or just a space and a lease you are considering — we will walk it and give you a written number. Call (917) 564-1006 or email zef@dacajconstruction.com. You can also book a meeting or see more of our commercial buildout work.