Historic window repair in NYC
Preserve architectural integrity while meeting energy codes - without compromising landmark character.
LPC-Compliant Documentation Landmarks commission-approved methods
Match Original Profiles custom wood window restoration
Acoustic Sealing closing structural air gaps helps reduce loud NYC street noise
$11M Coverage strong liability coverage for your property
The mechanics of
historic window deterioration
Wood rot, paint buildup, and deferred maintenance can lead to irreversible damage and Landmarks violations.
UNDERSTANDING “PRESERVATION VS REPLACEMENT”
Your historic building windows – whether 1890s brownstone double-hungs or 1920s casements – were engineered for repair, not replacement. Original old-growth wood has tighter grain and superior rot resistance compared to modern lumber.
Historic window sash systems used mortise-and-tenon joinery that can outlast contemporary construction when properly maintained.
THE HIDDEN COSTS OF WAITING:
Landmarks Violations & Fines:
Unauthorized replacement windows – especially vinyl or aluminum systems –can require removal and reinstallation of LPC-compliant historic reproduction windows at 3–5x the original cost. LPC has enforcement jurisdiction over 37,000+ buildings across 150+ historic districts.
Accelerated Wood Rot & Structural Damage:
Water infiltration through failed historic window openings doesn’t just damage the sash — it migrates to surrounding masonry, lintels, and interior plaster. A $1,200 historic window sash replacement can become an $8,000–$15,000 repair when rot extends to brick jambs, stone sills, and structural framing. In brownstones, moisture wicking through sandstone window surrounds accelerates façade spalling — costly deterioration that Local Law 11/FISP inspections flag immediately.
Energy Waste Without Storm Window Protection:
Single-pane historic windows without storm windows can waste 40–60% more energy than modern systems. A typical brownstone with 20 original windows can lose $2,000–$4,000 annually in excess heating and cooling costs. Exterior or interior storm windows can deliver 60–80% of modern energy performance while preserving original glass and frames — but only if installed before rot compromises the structure needed to support them.
THE BIG APPLE historic preservation protocol
We plan and install solutions that satisfy NYC Landmarks, energy code requirements, and preservation standards at the same time.
Schedule a site visit
Landmarks compliance assessment & documentation
Our historic window specialists document existing conditions with measured drawings, photograph original details, and assess the structural integrity of sash, frames, and surrounding masonry. For historic window repair and replacement projects in LPC-regulated districts, we coordinate with Landmarks staff before any work begins.
Сustom wood restoration & storm system integration
When frames and sash rails remain structurally sound, we restore rather than replace — repairing rot with epoxy, splicing in Dutchman patches where needed, reglazing with traditional putty, and refinishing with breathable linseed oil primers.
Installation & weatherproofing
We install using reversible methods that preserve original masonry openings and allow future restoration. Historic window sash replacement keeps original weights, pulleys, and hardware where functional. New installations use concealed modern components that don’t compromise the historic character. Weatherproofing includes rope caulk for seasonal gaps, spring bronze weatherstripping, and storm window integration coordinated with existing frames.Big Apple Window Company at work
More than 2 decades of experience in property maintenance.
Preserve character, gain performance
See the transformation. We restored original windows and added storm systems — meeting Landmarks requirements while cutting energy costs by 45%.
BEFORE
AFTER
Engineering specifications & guarantees
Clear specs. Straight answers. We provide documentation that meets Secretary of the Interior Standards and NYC Landmarks requirements.
Old-growth quality standards
Custom milled from vertical-grain Douglas fir or Honduran mahogany. Mortise-and-tenon joinery, traditional glazing putty, and linseed oil finishes. Period hardware reproduction.
Preservation-compliant insulation
Exterior storm windows: powder-coated aluminum to match the trim. Interior storms: low-profile acrylic with spring-loaded frames. Both systems are reversible per LPC standards.
Warranty protection
5-year restoration warranty. 10-year reproduction warranty. If historic wood window replacement or restoration work fails — wood rot returns, glazing fails, or joinery separates — we come back and make it right. No service fees.
Warranty transfers with the property.
Risk management
$11 million umbrella coverage. Strong liability coverage, including NY Labor Law §240/241 protection with no Action Over exclusions. LPC-compliant documentation and COA application support for landmark properties.
EXPERIENCE THE NEW STANDARD
Join 200+ landmark buildings and 10,000+ historic homeowners who've preserved architectural integrity while gaining modern performance.
While we’re on-site
Our historic preservation specialists spot related issues in pre-war buildings that come with window deterioration.
