01
What an alteration agreement is
An Alteration Agreement is a legally binding contract between the shareholder and the co-op corporation. It outlines what you can and cannot do, how the work must be performed, and the penalties for non-compliance.
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NYC Co-op Renovation Rules: What Homeowners Must Know Before Starting a Manhattan Apartment Renovation
A successful Manhattan renovation is as much about approvals, compliance, and coordination as it is about craftsmanship. Use this as company guidance, with the understanding that each building’s current documents and applicable agency requirements control.
A useful starting point
Good planning makes better questions possible.
02
Work hours are building-dependent
NYC law allows construction from 7AM–6PM. Most co-ops restrict work to 9AM–5PM, while some buildings run 9AM–4:30PM. Weekends and holidays are generally not allowed. The building’s current rules control the workable window.
03
Construction windows and security deposits
Construction windows are commonly 90–120 days. Exceeding the approved window can trigger liquidated damages, meaning daily fines. Security deposits are commonly $5,000–$20,000, depending on the building and its requirements.
04
Appliances and floor sequencing
In-unit washers and dryers are often banned because of waste-line strain and flood risk. Boards may also limit simultaneous renovations on one floor because of elevator congestion and noise.
05
Which DOB filing may apply
The filing path depends on the scope, building, and applicable professional review. A licensed design professional and/or DOB determines the classification; Corniel does not determine it independently. See the single DOB authority for the filing types and CO/TCO context.
Read the filing types overview ↗06
Lead-safe work in older buildings
Local Law 1 lead-paint requirements apply in pre-1960 buildings where children under 6 may reside. Lead-safe work practices, dust containment, and specialized cleaning are relevant during wall demolition, window replacement, sanding or surface preparation, and a full gut in a pre-war building.
07
The condo approval trajectory
A condo review commonly moves from scope submission to an independent reviewing architect, at the owner’s expense, then insurance verification with a COI that meets the building’s limits, followed by management’s letter of no objection. Condo review is typically 2–4 weeks; a co-op can take 8 weeks or more when third-party architectural review is required. The actual path remains building-dependent.
08
What belongs in the board package
A board package commonly includes drawings, a detailed scope, schedule, protection plan, COIs with the building-required wording, contractor license information, and building-specific forms.
09
Insurance wording can affect mobilization
Insurance limits and endorsements are set by the building and management requirements for the project. The COI must name the Co-op Corporation, Managing Agent, and Shareholder as Additional Insured, using the building’s required wording.
10
The lead time before demolition
A realistic pre-demolition lead time is commonly 3–5 months: Design & Architect 2–4 weeks; Board Submission & Review 4–8 weeks, with some boards meeting monthly; DOB Permit 2–6 weeks; and Procurement 4–12 weeks. These are planning ranges, not guarantees.
11
Triangle of Communication
Contractor ↔ managing agent ↔ DOB: this is the Triangle of Communication, where projects succeed or fail. The scope, filings, building requirements, schedule, and field decisions need to stay aligned across all three points.
12
Company guidance, building-dependent
We help coordinate alteration agreement requirements and DOB-related filings through licensed professionals when required. Final approvals remain with the building, board, or applicable agency.
13
Why the full picture matters
A successful Manhattan renovation is as much about approvals, compliance, and coordination as it is about craftsmanship.
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