A homeowner in Brooklyn Heights got three vinyl-window quotes before anyone mentioned the block was landmarked. The contractors measured, priced the job at a competitive $600 a window, and said nothing about permits. It was the co-op board, not the Department of Buildings, that flagged it — the building sits inside the Brooklyn Heights Historic District, the first one New York City ever designated, back in November 1965, and vinyl on a street-facing facade there isn't a gray area. It's an automatic rejection.
That story repeats across every borough with a historic district, and there are 150 of them covering roughly 37,900 designated properties. Our windows hub covers replacement costs and materials nationally; this one is specific to what the Landmarks Preservation Commission (LPC) will and won't let you install, and what it costs to do it right the first time.
The short version: Every window replacement on an Individual Landmark or inside a historic district needs an LPC permit filed through the agency's Portico portal. Vinyl is never approved on a primary, street-facing facade. Small buildings with historic one-over-one wood sash can sometimes switch to painted metal or fiberglass instead of wood — still not vinyl. Rear facades not visible from the street usually have no material restriction at all.
Why "just replace the windows" isn't a permit-free job here
Outside a historic district, swapping old windows for new ones is between you and DOB, if it needs a permit at all. Inside one of LPC's 150 districts, or on one of the city's 1,460 individual landmarks, the window itself is a protected architectural feature, the same legal category as the cornice or the stoop railing. Routine maintenance stays permit-free: reglazing with clear glass, repainting the existing color, caulking, weatherstripping, sash cord and chain replacement, and interior storm windows with clear glazing and no visible muntins. The moment the work changes the window — new sash, new material, new glazing pattern, or even painting it a different color — it needs LPC sign-off before a contractor touches the opening.
That sign-off comes in one of two forms. A Certificate of No Effect is staff-level review: LPC staff compare the proposal against the building's historic attributes and approve it administratively when it's a genuine match. A Certificate of Appropriateness requires a public hearing in front of the panel of Commissioners, and it's the path for anything that changes material, configuration, or appearance enough that staff can't sign off alone. Most straightforward in-kind wood-for-wood replacements clear at the staff level in a matter of weeks. Vinyl proposals, when they get filed at all, tend to land in front of the full Commission — and get turned down there.
What LPC actually lets you install, by building type
The material rules aren't one-size-fits-all; they scale with the building:
- Individual Landmarks: Material must always match what's historically there. If the building has wood sash, the replacement is wood.
- Small buildings in a historic district (six stories or fewer, under 40 feet of street frontage — the typical Brooklyn or Manhattan rowhouse): Material must match if the historic windows were wood. There's one specific carve-out: one-over-one wood sash may be replaced with painted metal or fiberglass. Not vinyl, under any circumstance, on the primary facade.
- Large buildings (seven stories or more, or more than 40 feet of street frontage): LPC allows more material flexibility, including some replacement materials that wouldn't be approved on a small rowhouse.
Even where material flexibility exists, configuration, sightlines, glass-to-frame ratio, finish, and operation (double-hung staying double-hung, casement staying casement) still have to match, with limited exceptions for accessibility or energy retrofits. LPC also caps how much the glass area can shrink when a new sash goes in — up to 6% glazing diminution for wood replacements, up to 10% for metal. A contractor who proposes a beefier, more energy-efficient frame that eats more than that into the glass area needs a specific justification, not just a better U-factor.
Secondary facades get real relief: visible secondary elevations still need configuration and finish to match, but non-visible facades — typically the rear of a rowhouse facing a shared yard — usually have no material-matching requirement at all. That's the legal basis for the common Brooklyn brownstone pattern: restored or reproduction wood on the parlor-floor street windows, and budget aluminum or fiberglass in the back where nobody on the sidewalk will ever see it.
Special windows get their own category. Stained glass, ornamental leaded glass, and other windows with what LPC calls "rare or distinctive traits" require every attribute — material, operation, configuration, details, finish — to match, plus a condition assessment before staff will review the application. If your Brooklyn brownstone still has its original parlor-floor stained transom, budget for a specialist, not a general window contractor.
What this actually costs, by facade
Contractors who work landmarked buildings regularly price the job in tiers, because the front and back of the same house are often different projects:
| Scope | Typical Cost |
|---|---|
| Restoring existing historic wood sash (repair, not replace) | $800 – $1,500 per window |
| Full custom wood reproduction sash, primary facade | $2,000 – $3,500 per window |
| High-end parlor-level or curved-opening reproduction | $2,500 – $7,500 per window |
| Painted metal or fiberglass, small-building exception | $1,500 – $2,500 per window (varies by manufacturer) |
| Budget aluminum/fiberglass, non-visible rear facade | $500 – $600 per window |
| Architect/expediter fees for LPC drawings & Portico filing | $2,000 – $5,000 per project |
That spread is why a ten-window Brooklyn brownstone job can land anywhere from $12,000 to $45,000-plus depending on how many windows face the street, whether any are special (stained or leaded glass), and whether the project needs a full Commission hearing or clears at the staff level. Skipping the process isn't a shortcut: LPC civil penalties start around $5,000 per violating window, and corrective work — tearing out unapproved vinyl and reinstalling an approved product — typically runs three to five times what doing it right the first time would have cost.
If you're in a co-op or condo: three approvals, in order
Landmarked co-ops and condos add a step most single-family owners skip. The sequence that actually works is board approval first, then LPC, then DOB:
- Co-op or condo board: Many boards keep an approved manufacturer and profile list specifically to keep the facade consistent unit to unit. Get board sign-off, or at least alignment, before spending money on drawings.
- LPC: File through Portico for a Certificate of No Effect or, if needed, a Certificate of Appropriateness. Expect three to four months for a clean application requiring a full hearing; a straightforward staff-level filing moves faster.
- DOB: A permit is required when the work changes an opening's size, involves structural elements, or touches a fire escape egress window. DOB will not accept the filing on a landmarked property until LPC has approved the work, so filing with DOB first, or in parallel, just creates a rejected application and lost time.
Reversing that order, or leaving the superintendent and managing agent out of early conversations, is the single most common reason a landmarked window project that should take one season stretches into two.
Common mistakes homeowners make on landmarked blocks
- Assuming a competitive quote means a compliant one. A window contractor who doesn't ask what district you're in, or doesn't mention LPC at all, is either unfamiliar with landmark work or planning to install without a permit. Ask directly whether they've filed Portico applications before, and ask for a recent Certificate of No Effect they've obtained.
- Proposing "vinyl that looks like wood" for the front of the house. LPC's rejection of vinyl on primary facades isn't about how convincing the wood-grain texture is. It's categorical. Save the vinyl conversation for a non-visible rear elevation, if your building qualifies.
- Skipping the DOB step because "it's just windows." If the new opening is a different size than the old one, or the work touches a fire escape window, DOB involvement isn't optional regardless of how LPC's review goes.
- Filing without dimensioned drawings. LPC applications need fully-dimensioned drawings (floor plans, elevations, sections), high-quality photographs of the facade and existing window details, and the proposed paint color. Incomplete submissions are the most common reason a staff-level review gets kicked up to a full hearing.
- Not budgeting for the special-window category. Original stained or leaded glass triggers a condition assessment and full attribute matching. Treat it as its own line item, not part of a general window contract.
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Get New York Window QuotesFrequently asked questions
Can I install vinyl windows on a landmarked house in NYC?
Not on a primary, street-facing facade. LPC treats vinyl as categorically inappropriate on primary elevations regardless of color or how closely it mimics wood muntins. Small landmarked buildings with historic one-over-one wood sash can sometimes switch to painted metal or fiberglass, but not vinyl. Rear, non-visible facades on many buildings have no material restriction at all.
Do I need a permit to replace windows in a NYC historic district?
Yes. Every window replacement on an Individual Landmark or inside a historic district requires LPC permit approval filed through Portico before work starts. Routine maintenance — clear-glass reglazing, same-color repainting, caulking, weatherstripping, and clear interior storm windows — stays permit-free.
What's the difference between a Certificate of No Effect and a Certificate of Appropriateness?
A Certificate of No Effect is faster, staff-level review for proposals that clearly match historic attributes. A Certificate of Appropriateness requires a public hearing before the Commissioners and applies when the proposal changes material, configuration, or appearance enough that staff can't approve it alone. Most vinyl proposals, when filed, end up in front of the full Commission and get rejected there.
How much does it cost to replace windows on a landmarked building in NYC?
Restoring existing wood sash runs $800-$1,500 per window; full custom wood reproduction runs $2,000-$3,500 per window; high-end parlor-level work can reach $2,500-$7,500 per window. Budget aluminum for a non-visible rear facade can run $500-$600 per window. Add $2,000-$5,000 in architect or expediter fees to prepare LPC-compliant drawings and file through Portico.
What happens if I replace landmarked windows without LPC approval?
LPC can issue a Notice of Violation with civil penalties starting around $5,000 per window, and can require the unapproved work be undone and redone to an approved standard. That corrective work typically runs three to five times what compliant work would have cost the first time. Violations surface during unrelated permit reviews, sale due diligence, and routine inspections.
How long does LPC window approval take?
A clean staff-level application can clear in a few weeks. A full Certificate of Appropriateness hearing typically takes three to four months from filing to decision. Co-op and condo projects should get board approval before the LPC filing, not after — reversing that order is a common cause of delay.
Who has to approve window replacement in a landmarked co-op building?
Three approvals apply in sequence: the co-op or condo board first, then LPC for the Certificate of No Effect or Appropriateness, then DOB for a permit if the work changes an opening's size, involves structural elements, or touches a fire escape egress window. DOB will not accept a filing on a landmarked property until LPC has signed off.