Slim French Sliding Window Profiles: Sections, Walls and Weights
A slim French sliding window is built from about two dozen extruded aluminium sections: upper and lower tracks, side frames, sash stiles and rails, interlocking stiles, mullions, corner connectors and snap-on covers. In lightweight economy series these sections have walls of 1.0 – 1.35 mm and weigh roughly 0.3 – 1.4 kg per metre. This guide explains what each profile does, gives indicative weights for a typical series, and lists the alloy, finish and tolerance points that fabricators should put on their profile orders. Metline supplies the aluminium profiles; window fabrication and installation are carried out by the window maker.
- Wall thickness
- 1.0 – 1.35 mm
- Section weights
- About 0.27 – 1.38 kg/m
- Alloy
- 6063-T5 / 6060-T66
- Finishes
- Powder coat, anodise, wood grain
What a slim French sliding window is
"French sliding window" is a trade term for a horizontal slider with narrow interlocking sash stiles and a large glass area. Two or more sashes run on rollers in tracks formed in the bottom frame, and their meeting stiles hook together to close the gap and resist wind.
Slim, lightweight series are designed for residential balconies, kitchens and bedrooms in mild climates, where cost and sightlines matter more than thermal performance. They usually take single glazing or thin insulated glass units, use non-thermally-broken frames, and rely on brush or rubber seals in the interlocks. Heavier, deeper series with thermal breaks are used for exposed façades, high-rise buildings and cold or very hot climates; see our guide to 72 mm French sliding window profiles for a deeper series.
Because each manufacturer's series has its own section shapes, the figures on this page are indicative values for one typical lightweight series. Always work from the system drawings and die drawings for the profiles you actually order.
Profiles in a typical slim French sliding set
| Profile | Function | Wall (mm) | Indicative weight (kg/m) |
|---|---|---|---|
| Upper sliding track (head) | Top frame member that guides the sashes and keeps them in the opening | 1.2 | 1.04 – 1.09 |
| Lower sliding track (sill) | Bottom frame with roller tracks and drainage; the most heavily loaded frame section | 1.2 – 1.35 | 1.09 – 1.38 |
| Side frame (jamb / edge seal) | Vertical frame members that close the sash edges against the wall | 1.2 | 0.51 – 0.87 |
| Fixed-light head (upper fixation) | Holds a fixed upper pane or transom above the sliders | 1.2 | 0.51 – 0.56 |
| Sash stile (vertical sliding) | Vertical sash members, including interlocking meeting stiles | 1.2 | 0.84 – 1.29 |
| Sash rail (horizontal sliding) | Top and bottom sash members carrying the glass and rollers | 1.2 | 0.74 |
| Mullion (intermediate column) | Vertical divider between fixed and sliding sections | 1.2 | 0.74 – 0.82 |
| Corner connector profile | Section cut into cleats that join frame corners | 1.2 | 1.14 – 1.20 |
| Cover plates | Snap-on covers for the lower track and edge seals, and reverse-side covers | 1.0 | 0.27 – 0.31 |
Indicative weights for one lightweight series with 1.0 – 1.35 mm walls. Section weight scales almost directly with wall thickness: the same shape at 1.4 mm weighs roughly 15 – 20 % more than at 1.2 mm.
The lower track carries the full weight of the sashes on its roller rails and must resist deflection and wear, which is why it is often the thickest and heaviest section in the set. Interlocking stiles must be stiff enough not to bow under wind pressure, because a bowed interlock opens a gap that leaks air and water.
Estimating profile weight for a window
Profile is bought by weight, so fabricators estimate kilograms per window from the cutting list. Multiply each cut length by the section weight per metre and add an allowance for saw cuts and offcuts (commonly 5 – 10 % depending on bar length and nesting).
| Member (1500 × 1200 mm two-sash window) | Length (m) | kg/m used | kg |
|---|---|---|---|
| Upper track | 1.5 | 1.07 | 1.61 |
| Lower track | 1.5 | 1.20 | 1.80 |
| Side frames (2) | 2.4 | 0.70 | 1.68 |
| Sash stiles (4) | 4.8 | 1.00 | 4.80 |
| Sash rails (4) | 3.0 | 0.74 | 2.22 |
| Total before allowance | 12.11 |
Illustrative calculation using mid-range indicative weights from the table above; real cutting lists include covers, cleats and glazing beads and depend on the series.
Alloy, temper and finish for window profiles
| Item | Typical specification | Why |
|---|---|---|
| Alloy | 6063 or 6060 (EN AW-6063 / EN AW-6060) | Extrudes thin, complex sections with a smooth surface and anodises well |
| Temper | T5 or T6 (T66 for 6060 in Europe) | Adequate strength for slim frames with good surface quality |
| Dimensional tolerances | EN 755-9 or EN 12020-2 for precision profiles; ANSI H35.2 in the US | Interlocks and snap-on covers only fit if tolerances are tight |
| Powder coating | Polyester powder, typically 60 – 80 µm, to Qualicoat or AAMA 2603/2604 | Colour, weather resistance; superdurable powders for strong sun |
| Anodising | 15 – 25 µm clear or coloured, to Qualanod or AAMA 611 | Metallic look and abrasion resistance |
| Wood grain | Sublimation transfer over powder base coat | Timber appearance without timber maintenance |
Wall thickness is a quality question as much as a cost one. Thin walls save metal but reduce screw pull-out strength, stiffness of the interlock and resistance to denting during handling. Many building codes and specifiers set a minimum wall thickness for main frame and sash members, commonly in the range of 1.2 – 1.4 mm for residential windows and more for large or high-rise openings, so check the requirement for your market before choosing a lightweight series. For deeper background see our aluminium window profile specification guide and 6063 extrusions.
Performance points to check
- Air and water tightness: sliding windows are tested for air permeability, watertightness and wind resistance (EN 12207, EN 12208 and EN 12210 in Europe; ASTM E283, E331 and E330 or AAMA/WDMA/CSA 101/I.S.2/A440 in North America). Slim series generally reach lower classes than heavy series.
- Drainage: the lower track needs weep slots and a stepped profile so that water entering the track drains outside.
- Interlock stiffness: the meeting stile limits the size of sash a slim series can carry in a given wind zone; follow the system's size limits.
- Thermal performance: non-thermally-broken slim profiles conduct heat; for energy-code compliance in cold or hot climates, a thermal-break series is needed.
- Hardware fit: rollers, locks and seals are designed for specific profile grooves; changing the profile changes the hardware.
How to order profiles for a French sliding window
- Identify the sectionsSend the system catalogue or die drawings with section codes, wall thickness and weight per metre for each profile.
- Set material and toleranceAlloy and temper (6063-T5 or 6060-T66), tolerance standard and any minimum wall thickness required by your market.
- Choose finishPowder coat colour (RAL or sample), anodised colour and thickness, or wood-grain pattern; protective film if needed.
- Quantities and lengthsKilograms or bar quantities per section, bar length (commonly 5.8 m or 6 m to suit containers).
- Documents and deliveryMill test certificate to EN 10204 3.1, coating test report, packing per bundle, and delivery terms (EXW, FOB, CIF or DAP).
References and standards
- EN 755-9 – Extruded rod/bar, tube and profiles: tolerances on dimensions and form
- EN 12020-2 – Extruded precision profiles in alloys EN AW-6060 and EN AW-6063: tolerances
- EN 14351-1 – Windows and doors: product standard, performance characteristics
- AAMA/WDMA/CSA 101/I.S.2/A440 – North American Fenestration Standard
- Qualicoat – Specifications for a quality label for coatings on aluminium for architectural applications
French sliding window aluminium (aluminum) profiles: FAQ
What wall thickness should sliding window profiles have?
Lightweight residential series use about 1.0 – 1.35 mm, with covers at 1.0 mm. Many specifiers require at least 1.2 – 1.4 mm for main frame and sash members, and more for large windows or high-rise buildings, so check local codes and project specifications.
Which aluminium alloy is used for window profiles?
6063 is used almost everywhere, and 6060 is common in Europe. Both extrude thin, complex shapes with a smooth surface that powder coats and anodises well, usually in T5 or T6 (T66) temper.
Why is the lower track the heaviest profile?
It carries the weight of the sashes on its roller rails, has to drain water and must not deflect between supports, so it usually has thicker walls and more material than the other sections.
Can a slim French sliding window meet energy codes?
Usually not in cold or very hot climates, because slim series are not thermally broken. Use a thermal-break series with insulating polyamide strips where U-value limits apply.
Does Metline make complete windows?
No. Metline supplies the aluminium profiles, finished as required, to window fabricators and system companies, who cut, assemble, glaze and install the windows.
Need profiles for a sliding window series?
Send your die drawings or series list, wall thickness, finish, quantities and destination. We will reply with availability and a delivered price.
