New York City's Heritage Specialists
Certified restoration of historic windows, stained glass, and landmark building elements across all five NYC boroughs — for over 17 years.
Founded by Henrique Lima, HM Conservation was built on a simple belief: that the windows and facades of New York's landmark buildings are irreplaceable — and deserving of the highest standard of care.
With over 17 years of hands-on experience, our team has restored historic wood sash, stained glass, cast-iron windows, dalle de verre panels, and ornamental metalwork across more than 80 landmark sites in all five boroughs. Notable projects include 70+ windows at the Dorilton Building and 1890s curved-glass brownstone restoration in Brooklyn Heights.
Our workshop in Newark, NJ is equipped for full in-house fabrication — from custom glazing to architectural millwork — ensuring every repair meets LPC approval standards before it ever reaches your building.
Every service follows NYC Landmarks Preservation Commission guidelines, with full documentation and approval management included.
Re-leading, glass replacement, structural reinforcement, and full panel restoration for historic stained glass and decorative leaded lights in churches, institutions, and landmarked residences.
Restoration of original wood sash, double-hung, casement, and fixed windows. Cast-iron, steel, and bronze window frame repair with period-accurate materials and profiles.
Expert repair and replication of faceted slab-glass panels — the mid-century modernist art glass found in NYC's landmark cultural buildings and houses of worship.
EPA RRP-certified lead paint removal and encapsulation on windows and building facades, fully compliant with NYC DOH regulations and LPC preservation standards.
When restoration isn't possible, we install historically appropriate replacement windows from three world-class manufacturers — each with certifications that satisfy LPC requirements.
Marvin's dedicated Historic Replacement product line was designed for exactly the buildings we serve. The Signature Ultimate collection features wood interiors with extruded aluminum-clad exteriors, six wood species, 19 exterior colors, and historic casing profiles that satisfy even the most exacting LPC reviewers.
Visit Marvin →Manufactured in Scoudouc, New Brunswick from sustainably harvested lumber from Norwood's own family sawmill. Their Historical Double Hung line is a favourite among NYC heritage restoration specialists for its authentic profile and exceptional durability.
Visit Norwood →Handcrafted in Antigua from genuine caoba (mahogany). Every window is custom — species, sash profile, hardware, and finish specified to your building. Carries AAMA, NFRC, NYC LPC, IMPACT, and Fire-Rated certifications. The gold standard for landmark mahogany replacement.
Visit Caoba →NYC's 36,000+ individually designated and district-contributing buildings require Landmarks Preservation Commission approval before any window work begins. We manage the entire process.
Every project follows a proven four-stage process designed to protect your building, your budget, and your landmark status.
We visit your property, evaluate the condition of all elements, photograph documentation, and deliver a clear scope of work — at no charge.
We prepare and file all required Landmarks Preservation Commission documentation, including CofA applications and material specification reports.
Approved work is fabricated in our Newark workshop using period-accurate materials, profiles, and techniques before a single piece reaches your building.
Our own certified crew handles installation, cleanup, and final documentation — including compliance records for your building's permanent file.
HM Conservation handled the Dorilton's windows with extraordinary care and precision. The LPC approval process — which we'd dreaded — was completely managed by their team. The results are indistinguishable from the original 1902 glazing.
Working with Henrique on our Adler Building restoration was a master class in historic preservation. His knowledge of period materials and LPC process saved us months of back-and-forth. Truly one of a kind.
As architects, we're particular about who touches a landmark building. HM Conservation has become our go-to for window and glazing restoration. Their documentation is impeccable and their craftsmanship is exceptional.
We serve all NYC designated landmark districts, individual landmarks, and contributing buildings. Below are the primary historic districts in each borough.
36+ Historic Districts
22+ Historic Districts
7+ Historic Districts
10+ Historic Districts
Tell us about your building and project. Our team reviews every inquiry and will confirm details within 24 hours. All assessments are complimentary and include a preliminary LPC status review.