Frameless Awning Window Aluminium Profiles
A frameless awning window hides the opening sash behind the glass: the pane is bonded to a slim aluminium subframe, so from outside the vent looks like a flush sheet of glass. A typical series uses about seven extruded sections with 1.2 – 2.0 mm walls. This guide explains each profile, gives indicative weights for one series and lists the alloy, finish and glazing points fabricators must check. Metline supplies the aluminium profiles; window fabricators make and install the windows.
- Opening type
- Awning, outward opening
- Main walls
- 1.6 – 2.0 mm
- Section weights
- About 0.19 – 1.66 kg/m
- Alloy
- 6063-T5 / T6, 6060-T66
What makes an awning window "frameless"?
An awning window is hinged at the top and opens outward at the bottom on friction stays, so it sheds rain while open. In a conventional design the glass sits in a visible sash frame held by glazing beads. In a frameless, or hidden-sash, design the glass is bonded to an aluminium subframe with structural silicone, and the subframe locks into a vent frame that sits behind the glass line.
The result is a facade where opening and fixed panes look identical from outside, which is why the system is popular for curtain-wall vents, ribbon windows and modern residential facades. The price of that appearance is more demanding fabrication: the bond between glass and aluminium carries wind and self-weight loads, so surface preparation and silicone application must follow a controlled procedure.
Each manufacturer's series has its own section shapes, so the figures below are indicative values for one typical series. Always work from the die drawings and system catalogue for the profiles you order.
Profiles in a typical frameless awning series
| Profile | Function | Wall (mm) | Indicative weight (kg/m) |
|---|---|---|---|
| Outer frame | Perimeter frame fixed into the wall opening; carries the vent and any fixed lights | 2.0 | 0.745 |
| Outward-opening vent (casement) frame | Opening frame hung from the stays; receives the glass subframe | 2.0 | 0.937 |
| Mullion / transom | Divides the outer frame into vent and fixed panes | 2.0 | 1.074 |
| Reinforced mullion / transom | Heavier divider for wide spans or high wind loads | 2.0 | 1.655 |
| Glass subframe (type A) | Hidden carrier to which the glass is bonded with structural silicone | 1.6 | 0.720 |
| Glass subframe (type B) | Alternative subframe for a different glass build-up or depth | 1.6 | 0.800 |
| Subframe cover plate | Snap-on cover that hides fixings on the inside face | 1.2 | 0.190 |
Indicative weights for one series. Weight scales nearly in proportion to wall thickness, so check the catalogue wall for each section before costing.
Estimating profile weight for one window
Profiles are bought by weight. Multiply each cut length by the section weight and add 5 – 10 % for saw cuts and offcuts. Example: an 800 × 1200 mm window with an awning vent above a fixed pane.
| Member | Length (m) | kg/m | kg |
|---|---|---|---|
| Outer frame (perimeter) | 4.0 | 0.745 | 2.98 |
| Transom | 0.8 | 1.074 | 0.86 |
| Vent frame (about 0.75 × 0.55 m) | 2.6 | 0.937 | 2.44 |
| Glass subframe | 2.6 | 0.720 | 1.87 |
| Cover plate | 2.6 | 0.190 | 0.49 |
| Total before allowance | 8.64 |
Illustrative calculation from the indicative weights above; the fixed pane also needs a subframe or beads, depending on the series.
Alloy, temper, tolerance and finish
| Item | Typical specification | Why |
|---|---|---|
| Alloy | EN AW-6063 or EN AW-6060 | Extrudes thin, accurate sections with a smooth surface for coating |
| Temper | T5 or T6 (T66 for 6060) | Strength for frames and mullions with good surface quality |
| Tolerances | EN 12020-2 or EN 755-9; ANSI H35.2 in the US | Subframes must clip into the vent frame accurately along the full length |
| Powder coating | Polyester powder to Qualicoat or AAMA 2603/2604/2605 | Colour and weather resistance |
| Anodising | Typically 15 – 25 µm to Qualanod or AAMA 611 | Metallic finish; often preferred on bonding surfaces |
Structural bonding and performance checks
- Bonding surface: the silicone manufacturer must approve the subframe finish (anodised or a specific powder coating) by adhesion testing before production.
- Bond design: bite and thickness of the structural silicone are calculated from wind load and pane size, following guidance such as ASTM C1401 or EN 13022 / EAD 090009.
- Glass weight: heavy insulated units may need setting blocks or mechanical retention as well as the bond, depending on local rules.
- Stays and transoms: friction stays are rated by sash weight and height; the reinforced mullion suits wider spans and higher wind zones.
- Weather and energy: windows are classified under EN 14351-1 (EN 12207, 12208, 12210) or AAMA/WDMA/CSA 101/I.S.2/A440. Where U-value limits apply, choose a thermal-break series.
References and standards
- EN 755-9 – Extruded rod/bar, tube and profiles: tolerances on dimensions and form
- EN 12020-2 – Extruded precision profiles in EN AW-6060 and EN AW-6063: tolerances
- EN 14351-1 – Windows and doors: product standard, performance characteristics
- ASTM C1401 – Standard Guide for Structural Sealant Glazing
- Qualicoat – Specifications for a quality label for coatings on aluminium for architectural applications
Frameless awning window aluminium (aluminum) profiles: FAQ
What is a frameless awning window?
An outward-opening, top-hinged window whose glass is bonded to a hidden aluminium subframe, so the vent looks like a flush pane from outside with no visible sash frame.
Which alloy is used for these profiles?
6063 or 6060 in T5, T6 or T66 temper. These alloys extrude thin, accurate sections with a surface suitable for powder coating, anodising and structural bonding.
How is the glass held in a frameless vent?
With structural silicone sealant bonded to the glass subframe, sized for wind load and pane size. The coating on the subframe must be approved by the sealant maker.
Does Metline make frameless windows?
No. Metline supplies the extruded aluminium profiles, cut to length and finished to order. Window fabricators assemble, glaze and install the windows.
Can the profiles be supplied in other wall thicknesses?
Wall thickness is set by the extrusion die, so changing it means a different die. Send the drawings and we will confirm what can be supplied.
Need awning window profiles?
Send the section list or drawings, finish, quantities and destination. We will reply with availability and a delivered price.
