They look alike from the sidewalk and are built completely differently. Which one a front needs is decided by height, support and water — not by looks.
If the glass is one storey tall and sits on the ground floor slab, it is a storefront. If it spans more than one floor or hangs off the edge of the slabs rather than sitting on one, it is a curtain wall. The names get used loosely on the street, but they are different systems with different engineering, and the wrong one in the wrong place is a leak or a failure waiting to happen.
| Feature | Storefront | Curtain Wall |
|---|---|---|
| Height | One storey, typically to 10–12 ft | Multi-storey, hung floor to floor |
| How it is supported | Sits on the slab; sill carries the weight | Hangs from the slab edges by anchors; spans between floors |
| Structural role | Infills an opening | Is the exterior wall |
| Profile depth | 1-3/4″ × 4½″ typical | 2½″ × 6″ to 10″+ |
| Glazing | Captured, from inside or outside | Pressure-plate, structural silicone, or unitised |
| Water management | Sill flashing and weeps | Internal drainage at every horizontal; rain-screen principle |
| Wind load | Low to moderate | Engineered per floor and elevation |
| Typical systems | Kawneer 451, YKK YES 45, Tubelite, Alutech | Kawneer 1600, YKK YCW, Cortizo, Alutech, Everest |
| Where we build it | Retail fronts, lobbies, ground floors | Corner elevations, full facades, LIC and Williamsburg new construction |
| Relative cost per sq ft | Lower | Higher; engineering and anchors add to it |
A storefront system is a frame of aluminum verticals and horizontals, about 4½ inches deep, that sits on the floor slab and fills an opening one storey tall. The sill carries the weight of the glass down to the slab; the head is fastened to the structure above but does not carry load. It is glazed from inside or outside with captured glass stops, and water that gets past the gaskets is caught in the sill and weeped out. It is the most economical way to glaze a ground floor and the right answer for every retail front, lobby and one-storey commercial entrance — 3915 Flatlands Avenue, Coney Island Avenue.
Its limits are its height and its structure. Above about twelve feet the mullions are not stiff enough for the wind load, and it cannot be hung between floors because it has no way to transfer load to the slab edge. Push a storefront system past those limits and it deflects, the glass cracks at the corners, and the joints open.
A curtain wall is an aluminum grid, six to ten inches deep, anchored to the edge of each floor slab and hanging in front of the structure — the “curtain.” Each floor’s section carries its own glass weight to its own anchors, so it can rise as many floors as the building has. The mullions are engineered for the wind load at that height and elevation; the anchors allow for the building moving and the aluminum expanding. Glazing is by pressure plate and cover cap, by structural silicone with no visible exterior frame, or by unitised panels assembled in the shop and craned into place.
Water management is the other difference. A curtain wall is drained at every horizontal member and pressure-equalised, so water that gets in is led back out at each floor rather than running down inside the system. That internal drainage is what lets it work forty feet up in a storm. The Anable in LIC is a full curtain-wall envelope; 24 Frost Street is a structurally glazed two-storey version; 2 Bushwick Avenue is a curved ribbon over three floors.
The most common confusion is the two-storey front — a retail floor with offices or a mezzanine above, glazed as one plane. It is a curtain wall, or at least a heavier “storefront” series designed to span two floors with intermediate anchors. Ordinary storefront framing at that height is the mistake we are most often called to look at on other installers’ work. The corner at 3915 Flatlands is storefront on the ground floor and curtain wall at the corner return for exactly this reason.
Storefront sits on the floor slab and fills a one-storey opening; curtain wall hangs from the slab edges and spans multiple floors as the building’s exterior wall. Different depth, engineering, glazing method and drainage.
Ordinary storefront, no: it is not stiff enough and has no way to carry load to the slab edge. A two-storey front is a curtain wall or a heavy storefront series designed for it, with intermediate anchors.
Curtain wall, per square foot, because of the deeper profiles, engineering, anchors and drainage. Storefront is the economical answer wherever it is the right answer.
Storefront: Kawneer, YKK AP, Tubelite, Alutech. Curtain wall: Kawneer, YKK AP, Cortizo, Alutech, Everest, Reynaers. Several brands make both, in different series.
Yes. Storefront repair — doors, closers, glass, leaks — is a large part of our work; curtain-wall repairs are usually glass replacement, gasket and pressure-plate work, and anchor inspection.
Storefront Doors & Framing Curtain Wall Systems Storefront Repair Commercial Aluminum Systems Structural Glazing
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 and the height of the opening. We will tell you which system it is, which it needs, and quote it.
