Renovating a co-op apartment in New York City involves a layer of complexity that condo, rental, and townhouse renovations do not: the alteration agreement. Understanding what this is and how to navigate it smoothly can mean the difference between a renovation that starts on schedule and one that sits in limbo for months while the board deliberates.
What an Alteration Agreement Is
A co-op alteration agreement is a contract between a shareholder and the cooperative corporation governing what work can be done in the apartment, what documentation is required, what contractors must provide, and who bears liability for any damage to common areas. Every building has its own version — some are a single page, others run to twenty pages. Read yours before calling any contractor.
What Typically Requires Approval
Rules vary by building, but most co-op alteration agreements require board approval for:
- Any work affecting building systems (plumbing, electrical, HVAC)
- Wall removal or addition (structural changes)
- Floor replacement (particularly in wet areas or where noise transmission is a concern)
- Wet area work (bathroom and kitchen plumbing changes)
- Window replacement
Most boards do NOT require approval for:
- Interior painting
- Decorative wall finishes (venetian plaster, roman clay, limewash)
- Millwork additions (built-in bookcases, trim, wainscoting) that don't affect building systems
- Carpet or area rug installation
- Lighting fixture changes at existing locations
What Your Contractor Needs to Provide
Most NYC co-op alteration agreements require contractors to provide:
- Certificate of General Liability Insurance (typically $1M per occurrence, $2M aggregate) naming the building corporation as additional insured
- Certificate of Workers' Compensation Insurance
- Copy of contractor's business license or trade license as applicable
- Written scope of work for board review
Some buildings also require an architect-stamped drawing for structural changes and a licensed plumber's or electrician's sign-off for relevant trade work. We have all required documentation ready and routinely provide complete alteration packages for co-op projects.
Working Hours and Building Rules
Most NYC co-op buildings restrict contractor working hours to weekdays between 8am and 5pm or 9am and 6pm. Elevator usage typically requires advance scheduling. Some buildings require dust barriers and specific disposal protocols. Know these rules before your contractors arrive on day one.