NYC Brownstone Full‑Floor Gut Remodel Permits & Budget 2025
- Richard Golding
- Nov 5
- 2 min read
Introduction
Brownstones in Harlem, Park Slope, and Fort Greene often hide 100‑year‑old plumbing and wiring. Modernizing means structural reinforcement, energy upgrades, and new layouts—all of which trigger Department of Buildings (DOB) filings. This guide explains permits, budget, and realistic timelines for a 2025 full‑floor gut remodel.
Understanding Permit Types: ALT1 vs ALT2
ALT1 applies when use or egress changes—such as combining units or altering exits—and requires a new Certificate of Occupancy.
ALT2 covers interior renovations that keep use and exits the same.
Removing load‑bearing walls, rerouting gas, or altering HVAC shafts demands a licensed Professional Engineer (PE) or Registered Architect (RA) filing.
Historic note: In LPC districts like Brooklyn Heights or UWS, you must secure Landmarks approval before DOB review. Timeline: Plan exam ≈ 25 business days; resubmittals add 4–8 weeks.
Typical Cost Breakdown (1,500 sq ft floor)
Category | Range (USD) | Key Details |
Demolition | $25K–$40K | Includes lead‑safe removal |
Structural framing | $60K–$100K | Joist repair, leveling |
MEP rough‑ins | $80K–$120K | Plumbing, electrical, sprinkler |
Finishes | $200K–$300K | Cabinets, tile, millwork |
Design & engineering | $25K–$45K | ALT1 drawings, site visits |
Permits & DOB fees | $8K–$15K | Filing + inspections |
Contingency | 10–15 % | For hidden damage |
Total: $600K–$950K.
Timeline & Inspections
Design + drawings: 6–10 weeks
DOB/LPC filings: 8–12 weeks
Construction: 16–24 weeks
Inspections: Plumbing → Electrical → Structural → Final CO (2–4 weeks).
Brownstones in Park Slope average 5–6 months from first submittal to completion.
Permit Coordination Tips
File LPC and DOB concurrently to save time.
Schedule utility disconnects 2 weeks before demo.
Include sprinkler layout on first submission to avoid objections.
Upload insurance certificates directly through DOB Now to prevent administrative holds.
Neighborhood Cost Snapshot
Harlem & Bed‑Stuy: $380–$480 / sq ft (non‑landmarked)
Park Slope & Brooklyn Heights: $520–$650 / sq ft (LPC areas)
Astoria & LIC: $400–$550 / sq ft (row‑house stock)
FAQ
Q: Can I live on another floor during construction? A: Not advisable. Gas and electrical shutdowns make partial occupancy unsafe.
Q: Do sprinklers become mandatory? A: Yes for 3‑story multi‑families under Local Law 26.
Q: When do I receive my new Certificate of Occupancy? A: Usually 2–4 weeks after final inspections.
NYC DOB – Alteration Filing Guidelines