The material Landmarks expects and the one that lasts longest maintained. Clad or solid, which lines we install, and what gets approved on a historic street.
Every window in New York built before the middle of the last century was wood, which is why wood is what the Landmarks Preservation Commission expects on a historic street facade and why the double-hung is its shape. Wood insulates well, is stable, and can be milled to any profile — including the exact profile of the original in a landmark district. It is also the most expensive of the four common frame materials and the only one that needs paint.
Clad wood solves the paint problem: a wood frame and sash with an aluminum or fiberglass skin on the exterior, factory-finished, and the wood exposed inside. It is what we install in nearly all landmark work — Pella, Marvin and Andersen all make clad lines — and what a co-op board usually specifies when it says “wood.” Solid wood inside and out is for the restoration purist and the owner who will keep up the painting.
| Line | Exterior | Character | Where we have used it |
|---|---|---|---|
| Pella Reserve / Architect / Lifestyle | Aluminum-clad or wood | Traditional profiles, divided lites, casements and double-hungs | 343 Hoyt Street, Coleridge Street, Amherst Drive |
| Marvin Ultimate / Signature | Aluminum-clad or wood | Landmark-grade double-hungs; Low-E3 argon; ENERGY STAR | East 71st Street |
| Andersen 400 / E-Series | Vinyl-clad (400) or aluminum-clad (E-Series) | Wide range; E-Series for custom colours and sizes | Andersen |
On a street facade in a historic district, Landmarks reviews the material, the operating type, the profile of the frame and sash, the muntin pattern and width, and the glass. Clad wood is routinely approved when the profile matches the original; the aluminum cladding is accepted because it reads as painted wood from the street. Simulated divided lites with an exterior bar, interior bar and spacer bar between the glass are the standard approval; grilles between the glass alone usually are not. We measure the original, draw the profile, and submit the application with the drawings — see landmark window replacement in Carroll Gardens and Upper West Side landmark windows.
A pocket replacement inside the old frame shrinks the glass and leaves the old frame’s air leaks; on a landmark facade it is also usually refused, because the old frame stays visible. Landmark wood windows are installed brick-to-brick: the old frame comes out to the masonry, the new full-frame unit goes in, the perimeter is insulated, flashed and sealed, and the interior trim is rebuilt. It is the more expensive method and the only one that gives the new window the whole opening. See brick-to-brick or pocket.
Large modern openings and window walls: aluminum. Rental programs where cost per opening decides: uPVC. Oceanfront exposure without a clad exterior: no. For the full comparison see aluminum vs uPVC vs wood vs fiberglass. Where a house wants the look of clad wood at a lower price, the Pella and Marvin fiberglass lines are worth pricing.
Wood and clad wood come in the same three product lines. Budget wood is thin on the ground — Andersen’s 200 Series and Marvin’s Essential (a fibreglass frame with a wood-look interior option) are the entry points, and most true budget windows are vinyl or composite instead. Standard wood is Pella Lifestyle, Andersen 400 and Marvin Elevate: wood interiors, aluminium- or fibreglass-clad exteriors, named hardware, factory finishes. Premium wood is Pella Architect Series and Reserve, Andersen A-Series and E-Series, and Marvin Signature Ultimate: true divided lites, period profiles, any species and stain, custom sizes and shapes — the line landmark work is done in, as on the East 71st Street townhouse. The tier decides how closely the window can match an original and how far it can go past the catalogue.
| Clad wood | All-wood (painted or primed) | |
|---|---|---|
| Exterior | Extruded aluminium or fibreglass skin over the wood, factory-finished in any colour | Wood, painted on site or factory-primed; repainted every 7–10 years |
| Interior | Bare, stained or painted wood: pine, Douglas fir, mahogany, oak, cherry | Same |
| Landmark facades | Approved where the profile and sightline match; the Commission looks at the shape, not the skin | The traditional answer; sometimes required on the most sensitive facades |
| Maintenance | Wash the cladding; refinish the interior when the room is repainted | Exterior paint cycle; check putty and sills yearly |
| Lifespan | 40+ years; the wood is protected | 40+ years if painted; far less if neglected |
The muntins are what the Landmarks Preservation Commission looks at first. True divided lites (TDL) are separate pieces of glass in each opening, each its own small insulated unit, held by real muntins with a face profile and a shadow line — the closest to the 1880s original and the most expensive. Simulated divided lites (SDL) are one large insulated unit with muntin bars bonded to both faces of the glass and, in the good versions, a spacer bar inside the unit between them; from the sidewalk they read as true lites, and most landmark approvals are SDL with the internal spacer. Grilles between the glass are a bar inside one sealed unit and nothing on the surface; they read as a grey line in sunlight and are refused on street facades. We draw the muntin profile — ogee, putty, square — and the pattern to match the original, which is what gets a submission approved.
Pine is the default interior in every line and stains well; Douglas fir and mahogany are the upgrades where the window is the joinery of the room; oak and cherry are available in the premium lines. Interiors come factory-primed, painted in the maker’s palette, or stained and clear-coated. Exterior cladding takes any colour, including the dark bronzes and blacks the Commission approves for pre-war facades. Hardware in the standard lines is named — Truth and Amesbury on the American windows — in brass, bronze, nickel and black; the premium lines add period-pattern sash lifts, locks and casement stays, and the landmark hardware article covers matching the originals.
Wood windows in pre-war buildings are almost always replaced brick-to-brick: the old frame, the parting beads and the weight pockets come out, the pocket is insulated and closed, the opening is squared and the new frame is set on shims with a sill pan and a continuous exterior seal, then the interior stops and trim are rebuilt to match. On a landmark facade the exterior brickmould and sill profile are drawn to match the original and reviewed with the window. On a new house the clad units are set into the rough opening with a sill pan and taped to the weather barrier. Either way the wood interior is the finish carpentry of the room, and the trim is fitted to it rather than the window to the trim. See window replacement and the landmark guide.
343 Hoyt Street in Carroll Gardens (Pella, landmark renovation), Coleridge Street in Manhattan Beach (Pella casements with divided lites and French doors), East 71st Street on the Upper East Side (Marvin Ultimate on the street facade), the Tower House (a Marvin outswing terrace door beside custom steel windows). Wood is also what we reach for on the front of a brownstone when the rear is aluminium, so the street reads as it should and the garden gets the big glass.
Both have a wood frame and sash. Clad wood adds a factory-finished aluminum or fiberglass skin on the exterior so the outside never needs paint; the wood is exposed inside. Solid wood is finished on both faces and needs exterior paint every few years.
Routinely, when the profile, operating type and divided-lite pattern match the original. The cladding reads as painted wood from the street. We prepare the application with profile drawings.
Pella, Marvin and Andersen, in their clad and solid-wood lines. Members of our installation team have completed Marvin installation training.
Maintained, longer than any other material — many New York wood windows are a century old. Clad wood removes the maintenance. Hardware and weatherstripping are what wear.
Yes. Wood insulates about as well as uPVC, and with Low-E argon glazing a clad wood window meets the energy code with margin. Marvin Ultimate units on East 71st Street are ENERGY STAR rated.
True divided lites are separate glass units in each opening held by real muntins; simulated divided lites are one large unit with muntin bars bonded to both faces and a spacer inside. Landmarks usually approves SDL with the internal spacer and refuses grilles between the glass.
Budget: Andersen 200 Series, Marvin Essential. Standard: Pella Lifestyle, Andersen 400, Marvin Elevate. Premium: Pella Architect Series and Reserve, Andersen A-Series and E-Series, Marvin Signature Ultimate — the landmark line.
No: the aluminium or fibreglass cladding is factory-finished and is washed, not painted. The wood interior is refinished when the room is repainted. All-wood exteriors need a paint cycle every 7–10 years.
Stained glass: how a panel is made · Budget, standard or premium? The three window lines explained · Pella Marvin Andersen Double-Hung Windows Landmark Windows Material Comparison
About this page. Written by Alex GC Inc. d/b/a Alex Glass Construction and reviewed before publication by Aleksandr Chernovolenko, Managing Partner, with our design and estimating lead and a field foreman. Our foremen hold the NYC DOB Site Safety Training supervisor card and our crews the 40-hour worker card; we are certified to fabricate, install and service Alutech and Everest aluminum systems. Facts are drawn from our own projects, manufacturer test data and the applicable codes; where we are giving an opinion, we say so. Last reviewed September 2026. Credentials
Send a photo of the facade and the existing window. We will tell you which line matches, what Landmarks will want, and quote brick-to-brick.
