A glass sliding door size is not one number. In a retail catalogue it is a stock width and height you pick from a shelf. In a system-door factory it is the rough opening of your wall, bounded by the series you choose, the panel-weight ceiling of its hardware, and the glass build you specify. This article separates the four numbers that all get called “size”, shows why the imperial-to-metric step is where projects quietly go wrong, and gives you the ALPES published limits you can design against.
Before you can order anything, agree on which “size” a drawing is showing. The same word hides four different measurements, and only one of them reaches the factory.
| Term | What it actually is | Who writes it | What you use it for |
|---|---|---|---|
| Nominal called size | A short name like “60×80” used in catalogues and quotes | Marketing / sales | Talking about the product, never ordering it |
| Overall unit size | The actual frame outside edge to outside edge | Manufacturer | Checking it fits the wall thickness |
| Rough opening | The framed hole in the wall, larger than the unit | Architect / builder | The only number that goes on the purchase order |
| Net clear opening | The free passage after the sliding leaf stops | Hardware + configuration | Egress, furniture, wheelchair access |
On a purchase order, only the rough opening in millimetres, with the wall build-up, is the number that reaches the factory. Nominal names and overall sizes are useful for discussion; they are not the order.
Public supplier guides agree on the retail picture. Gladiator, SizeVista, OpenSliding and DFW Glass Mart all list stock two-panel sliding glass doors at 60, 72, or 96 inches wide and 80 or 82 inches tall. Those numbers describe vinyl and aluminium units kept in stock for production homes. They are a starting point, not a limit, for a made-to-measure system door. When you read about sliding door sizes, separate the shelf sizes from the engineered sizes: one is a warehouse pick, the other is a drawing.
A glass sliding door built to a project is measured to the opening, not pulled from a shelf. That is the default mode for a system manufacturer, not a premium option.
One inch is 25.4 mm — exact arithmetic. But the converted value almost never lands on a clean metric number, and a metric catalogue walks a different modulus, usually 100 mm or 300 mm steps. The gap between the converted value and the listed module is where the frame, the gasket and the reveal live.
| Nominal | Inches | Exact millimetres | Nearest metric module | Gap |
|---|---|---|---|---|
| 60×80 | 60 × 80 | 1524 × 2032 | 1500 × 2100 | 24 / 68 mm |
| 72×80 | 72 × 80 | 1829 × 2032 | 1800 × 2100 | 29 / 68 mm |
| 96×80 | 96 × 80 | 2438 × 2032 | 2400 × 2100 | 38 / 68 mm |
| 60×48 | 60 × 48 | 1524 × 1219 | 1500 × 1200 | 24 / 19 mm |
A 60 × 48 inch opening converts to 1524 × 1219 mm, but a metric system catalogue is built on 100 mm and 300 mm steps, so the nearest listed module is 1500 × 1200 mm. Those 24 mm and 19 mm gaps are not rounding noise — they are where the frame, gasket and reveal sit. Ordering “1524 × 1219” from a metric factory usually means a custom cut, not a standard line. Reading about a standard sliding door size only helps if you also know which measuring rule produced the number.
ALPES builds glass sliding doors as made-to-measure system products. Three series carry published frame and panel limits you can use at the design stage.
| Series | Frame wall width | Single sash max | Pulley capacity | Glass |
|---|---|---|---|---|
| SL155 | Four-track 155 mm | 2800 × 2600 mm, 7.5 m² | 400 kg, 20-wheel self-balancing | 24A insulated |
| SL112-167 | Single / two 112 mm, three 167 mm | Driving capacity 220 kg | 220 kg per sash | 24A insulated |
| SL126-182 | Two 126 mm, three 182 mm | Up to 2500 × 3000 mm, ~7 m² | Reinforced to 3.0 mm locally | 27A inert-gas |
Frame depth is a series attribute, not a function of track count. The four-track SL155 is 155 mm deep, while the three-track SL126-182 is 182 mm deep. Do not specify “more tracks means deeper frame” — verify the series sheet before you write the wall pocket.
A sliding door’s largest panel is set by how much glass the pulley and frame can carry, not by a size table. Public supplier examples put a 4 ft by 10 ft tempered insulated panel above 200 lb; our arithmetic using the rule of thumb of about 2.5 kg per square metre per millimetre of glass thickness lands in the same range.
| Glass build | Approx weight per m² | Example 1.2 × 3.0 m glass mass |
|---|---|---|
| 6 + 12A + 6 (~12 mm glass) | ~30 kg/m² | ~108 kg |
| 8 + 12A + 8 (~16 mm glass) | ~40 kg/m² | ~144 kg |
| Impact laminated IGU (heavier build) | ~40 to 50 kg/m² | ~150 to 180 kg |
ALPES publishes 200 kg pulleys on TS130 and SL112-167 and a 400 kg 20-wheel self-balancing pulley on SL155. Because glass mass scales with thickness, the maximum panel for a heavier build is lower than for a lighter one. Ask for the max panel against your exact glass build, not against the series name. A bigger series does not automatically mean a bigger panel if the glass is heavier.
The frame wall width is the minimum net wall depth the door needs. ALPES sliding series span 112 mm (single and two-track SL112-167) to 182 mm (three-track SL126-182). Before you choose a series, send the factory the wall build-up from outside to inside — cladding, insulation, structural wall, internal finish — so the frame seats without furring out the opening. A glass sliding door black frame is one of the finish options, so custom also covers colour: Ice Cream White, Aurora Gray, Starry Sky Gray, Brown Coffee, or a matched colour. Decide finish and batch rule together, because the colour is applied to the profile before assembly.
| Scenario | Stock retail unit | Made-to-measure system | Which to choose |
|---|---|---|---|
| Replacing a 60×80 in a production home | Fits the opening, short lead time | Possible but slower and costlier | Stock, if the opening is true |
| A 2.4 m wide villa opening | Often not stocked at that width | Built to the millimetre | Made-to-measure |
| A 3.0 m tall lift-slide | Rarely available | Within SL126-182 published limit | Made-to-measure |
| One colour batch across 40 units | Batch may differ between shipments | One production batch, phased delivery | Made-to-measure, batch-controlled |
ALPES supplies the door, the hardware (ROTO, Winkhaus, CMECH, Wehag), the profiles (6060-T66 aluminium), the thermal break (PA66GF25 multi-chamber), and the submittal drawings. The sliding line does not carry a published whole-door K value — request the value against your glass build, because it is a system number, not a single fixed figure. ALPES does not hold your local country certificates or project approvals, and does not sign the wall perimeter seal; those belong to your project’s responsible parties. Treat the door as one component of the building envelope, not the whole envelope.
For retail stock units, yes: 60, 72, and 96 inches wide by 80 or 82 inches tall are widely listed. For a system door built to a project, the “size” is your rough opening, engineered within the series limits above.
Supplier guides commonly call for about half an inch to one inch of clearance per side beyond the unit frame, so the installer can plumb, level and square the frame. Confirm the exact tolerance on the series spec sheet rather than assuming a universal number.
Yes. Custom width and height is the normal mode for a system manufacturer. The limit is not a catalogue list but the series frame depth, the pulley capacity, and the glass mass of your chosen build.
The panel weight against the pulley rating. Glass mass grows with thickness, so a heavier build lowers the maximum panel even within the same series. Ask for the max against your glass, not the series name.
No. Frame depth is a series attribute. The four-track SL155 is 155 mm deep while the three-track SL126-182 is 182 mm deep, so more tracks can mean a shallower frame, not a deeper one. Verify the sheet.
Rough opening in millimetres, wall build-up, series and frame depth, glass build, panel configuration, finish and batch rule. With those, the factory returns a drawing and a quote rather than a catalogue line.
Before you send the order: name the rough opening in mm (not the nominal), state the wall build-up, pin the series and frame depth, fix the glass build, and name who signs the perimeter seal. Do that and “custom size” stops being a risk and becomes a drawing.
