New construction and renovation · custom stainless steel and aluminum designs · clear, low-iron, tinted and coloured glass · built to the NYC guard code
A glass railing is two things at once. To the architect and the owner it is the part of a balcony, terrace, roof deck or stair that disappears — the guard that lets the view through. To the building code it is fall protection, held to the same structural standard as a welded steel picket rail, with a second rulebook for the glass laid on top. Alex GC designs, fabricates and installs glass railing systems for new construction and renovation across New York City, New Jersey and eastern Pennsylvania, in stainless steel and aluminum, with a range of glass colours and finishes. Every system we build starts from the code and the loads and only then goes looking for the sightline the design wants, because a railing that looks right and fails inspection is worth nothing.
This page is written for the two people who usually have to agree on a railing: the designer who wants the least metal possible, and the person responsible for it standing up. The short version is that both can have what they want, but not in every combination, and the trade-offs are specific.
On a new building the railing is not an afterthought bolted to a finished slab; it is part of the structure from the drawings onward, and that is when it is cheapest to get right. New construction glass railing work is where we do most of our volume — balconies and terraces on multi-family buildings in Brooklyn, Queens and Manhattan, roof decks on new condominiums, and the stair and mezzanine guards inside them. Recent examples are on our portfolio pages for 5-13 47th Road in Long Island City, 2535 Frederick Douglass Boulevard in Harlem and 61 Avenue U in Brooklyn.
What new construction lets us do that a retrofit does not: set the base-shoe anchors into the slab edge at the right centres before the topping goes down, recess the shoe into a pocket so the glass appears to rise straight out of the floor, coordinate the waterproofing membrane so it runs under and up the shoe rather than being cut around it, and align the railing module to the window module above so the facade reads as one composition. Those are coordination decisions with the structural engineer, the waterproofer and the window installer, and on a project where we are also supplying the windows and curtain wall — as we were at 2535 Frederick Douglass — they happen inside one company.
The sequence matters. The shoe goes on after the slab edge is finished and before the deck surface; the glass goes in late, after the trades that break things have left. Glass panels stored on site for three months are glass panels that get chipped, and a chipped edge on a tempered guard panel is a replacement, not a repair.
The metal in a glass railing is the part you are supposed to not notice, which makes the choice of it more consequential, not less. We fabricate custom-designed stainless steel and aluminum glass railings to the drawings, and the two metals are not interchangeable.
Stainless is the choice when the metal is on show: slim posts, round or square top rails, standoffs and clamps, all in a brushed, mirror or bead-blast finish. Outdoors and anywhere within reach of salt air we use grade 316, which holds its finish on Staten Island, the Rockaways and the Jersey Shore where 304 will tea-stain in a season. Indoors, 304 is fine and less expensive. Stainless is stiffer than aluminum for a given section, so posts can be slimmer, and it takes a weld that can be ground invisible — which is what a custom curved or raked stair rail needs.
Aluminum is the choice for base shoes and for any system where the metal is meant to vanish or to match the windows. It is extruded, so the shoe profile is exact and consistent along a long run; it is light, which matters on a slab edge; and it takes a powder coat or anodized finish in any colour, including the dark bronze and black that match most contemporary window systems. An aluminum shoe with an aluminum top rail powder-coated to the window colour is the quietest railing we make. Its limits are that it cannot be welded and polished like stainless, and that it needs isolating from stainless anchors so the two metals do not corrode each other.
The most common custom specification combines them: an aluminum base shoe for the extrusion and the colour match, stainless standoffs or a stainless cap rail where hands and eyes land. Send us the drawings, or a photograph of a railing you want ours to look like, and we will tell you which metal goes where and what it will cost.
Clear is the default, but it is not the only option, and on a railing the glass is thick enough that the choice shows. All of these are available in laminated safety construction suitable for guards.
One caution that comes from the safety side: whatever the colour, the panel is still a laminated structural guard and is specified as one. A tinted panel is not a lighter panel.
The design brief for almost every glass railing is the same: as little metal as possible. There are three places metal can go, and each has a cost.
Posts. The most visible and the least expensive. Posts carry the load down to the structure and the glass becomes infill, which means the glass can be thinner and tempered rather than laminated in some configurations. Right for long runs on a budget, for stairs, and for anywhere the fixing into the structure is difficult.
Base shoe. The glass is cantilevered from a continuous aluminum channel at the bottom, so there are no posts at all and the run reads as a line of glass. The shoe can sit on the surface, be bolted to the fascia so nothing shows on the deck, or be recessed into a pocket so the glass grows out of the floor. This is the contemporary standard for new construction balconies.
Top rail. With a base shoe, the question becomes whether there is a rail across the top. A continuous cap rail ties the panels together, gives the hand something to hold, and — the part that matters for approval — means the guard still stands if one panel breaks, because the neighbours carry it. Without a rail, each panel stands alone and must be laminated and engineered to survive impact on its own. Rail-less frameless glass is the most transparent option and the most demanding specification; we build it, and we will tell you when the exposure or the budget argues for the rail instead.
LED edge lighting. A low-profile LED channel in the base shoe lights the bottom edge of each panel so the glass carries the light up through its edge. It reads as a line of light after dark and costs little to add at fabrication; it is expensive to add later. Our 61 Avenue U terraces are an example.
Everything above is design. This is the part that decides whether the railing passes inspection and whether it holds when it has to. A glass guard is not decoration and it is not joinery; it is fall protection held to the same structural standard as a welded steel picket rail, with a second, glazing-specific rulebook applied on top. The two failure patterns we are called to are consistent: the geometry is right and the glass is wrong, or the glass is right and the geometry misses the code.
Height. New York City requires a minimum guard height of 42 inches at open-sided walking surfaces. NYC does not allow the 36-inch residential exception found in the residential code — in the five boroughs a guard at a single-family house is held to the same 42 inches as one on an office tower. This catches people who have worked elsewhere.
Openings. A 4-inch sphere must not pass through any part of the guard. On a glass system that usually concerns the gap at the base and between panels rather than the panel itself.
Where guards are required. Any open-sided walking surface more than 30 inches above the surface below: terraces, balconies, stairs, mezzanines, occupiable roofs, landings.
Under NYC Building Code §1607.8.1 and its subsections, the assembly has to carry three separate load cases, and they are not applied at the same time: 50 pounds per linear foot, uniform, in any direction at the top; 200 pounds concentrated, in any direction at any point along the top, not concurrent with the uniform load; and infill loading of 50 pounds concentrated over one square foot on intermediate rails, balusters and panel fillers, plus 50 pounds per foot downward and upward.
Then the requirement that governs the glass itself: under §2407.1.1, structural glass guard elements are designed with a safety factor of not less than four. That single clause is why a glass guard is thicker and more expensive than people expect, and it is not negotiable.
Railing in-fill glazing must be an approved safety glazing material with a minimum nominal thickness of ¼ inch, and fully tempered or laminated glass must comply with Category II of CPSC 16 CFR 1201. In practice structural guard panels are considerably thicker than the minimum.
Laminated, not monolithic tempered. This is the specification point that matters most. Tempered glass alone fails completely — it converts to granules and the barrier is simply gone, at height, over a pavement. Laminated construction keeps the fragments bonded to the interlayer so the panel stays in the opening after breakage. Exterior balusters and in-fill panels in wind-borne debris regions must be laminated Category II Class A glass under §2407.1.4.1. And where the top rail is supported by the glass itself, the assembly must be impact tested and remain in place after impact under §2407.1.4.2 — the technical reason a free-standing frameless balustrade without a top rail is a much more demanding specification than one with a cap rail.
We also specify heat soaked glass on guard panels. Heat soaking screens out the nickel sulphide inclusions that cause tempered glass to fail spontaneously years after installation — a risk that is academic in a shop window and unacceptable forty floors up. One restriction worth knowing: glazing may not be used in handrails or guards in parking garages, except in pedestrian areas not exposed to vehicle impact.
For new construction, send the architectural drawings and the slab-edge details, and tell us whether the engineer has set a design pressure. For a retrofit, send photographs of the edge the railing will sit on, the run lengths, and a picture of any railing whose look you want. We will come back with the system that meets the code at that exposure, the metal and glass options that fit the design, and a price — and if the frameless version you have in mind is going to cost twice what a shoe-and-rail version will and look almost the same, we will say so.
Get a custom quote for your glass railing project today
