A full-floor brownstone gut renovation in NYC costs $600K–$950K depending on neighborhood, takes 5–6 months from permit to completion, and requires ALT1 permits plus LPC approval if in historic districts. Budget 25–30 business days for DOB plan review. Lead-safe demolition, MEP upgrades, structural reinforcement, and proper permit sequencing are critical to avoid violations and cost overruns.

Brownstone floors carry history and hidden issues. Reclaimed oak and heart-pine look authentic but need careful acclimation and flatter substrates. Engineered wood is stable over old joists. Cork reduces footfall noise. Stone elevates kitchens and baths but adds weight and requires deflection checks. Confirm when LPC staff approvals and DOB filings apply, and use lead-safe practices for old finish removal.