Views: 0 Author: Site Editor Publish Time: 2025-06-18 Origin: Site
Why are architects obsessed with ever thinner window frames? Aluminium profiles have shrunk from 105 mm to a stunning 15 mm. More glass means brighter rooms, wider views, smaller energy bills. So, how slim can an aluminum window safely go? This post reveals the limits, benefits, and design tips.
In window design, “slim” refers to the sight-line—the visible width of the frame. A smaller sight-line means a larger glass area and cleaner design.
| Profile Type | Visible Frame Width | Industry Label |
|---|---|---|
| Standard | 70–105 mm | Traditional / Common |
| Slim | 25–50 mm | Contemporary / Minimal |
| Ultra-Slim | 15–20 mm | Frameless / High-End |
When frames drop below 50 mm, they are “slim.”Go under 20 mm, and they become “ultra-slim.”
More daylight into your room
Cleaner views with fewer visual interruptions
A modern, minimalist appearance
In real-world use, aluminium frames can have structural depths as low as 14 mm. That’s nearly as thin as a pencil. They’re commonly used for:
Heritage window retrofits
Historic sash window replacements
Interior partitions in luxury spaces
But slim isn’t everything. They still must:
Support glazing loads
Resist strong winds
Stay watertight and safe
Meet building performance codes
Basic aluminium can’t support large glass with slim frames. High-strength alloys like Duranium solve that, offering up to 40% more strength. This allows for thinner, stronger, longer-lasting window frames.
Thermal breaks are added between the inner and outer parts of the frame. They improve insulation and reduce heat loss. Slim aluminium systems now include:
Polyamide thermal breaks
Foam-filled chambers
Sealed double or triple glazing
Uw values under 1.5 W/m²K are easily achieved, even with ultra-slim designs.
Glass is heavy—up to 40 kg per square metre.
Slim frames use:
Steel reinforcements
Deep glazing rebates
Smart internal geometry
Slim frames pass tough global standards like:
AS1288 (Australia)
EN 12211 (Europe)
PAS 24 / SBD (UK)
They handle:
Wind loads up to 3.5 kPa
Water resistance at 600 Pa
Air leakage below 0.5 m³/hr/m²
| Window Type | Max Size | Notes |
|---|---|---|
| Casement | 1.2 m × 2.2 m | Side or top hung |
| Tilt-turn | Up to 2.3 m tall | Inward opening, full locking |
| Sliding Panel | Up to 3 m high | Requires precise rollers |
| Fixed Glazing Wall | 4 m × 6 m+ | For ultra-slim structural look |
Modern frames are produced with tolerances of ±0.15 mm. That means:
Perfect joints
Consistent strength
Smoother finishes
Ultra-slim frames hide:
Steel rods in hollow profiles
Snap-in gaskets with no visible edges
Built-in drainage channels
All the performance, none of the bulk.
15 mm vertical sight-line
20 mm horizontal reveal
RW48 acoustic rating
Used in homes, galleries, and high-end offices
Some glass is mounted off-centre to allow:
Thicker glazing units
Better insulation
Stronger sealing
Slim outside, strong and smart inside.
| Feature | Ultra-Slim Aluminium Frame |
|---|---|
| Minimum visible sight-line | 15–20 mm |
| Minimum frame depth | ~14 mm |
| Maximum panel size | Up to 3 m tall, 6 m wide (fixed) |
| Thermal performance | 1.2 – 1.5 W/m²K |
| Structural strength | Up to 40% stronger alloy |
Aluminium frames now go as slim as 15 mm—strong, warm, and sleek. New tech like nano thermal breaks will make them even better.
Want a custom slim design? Talk to an expert aluminium window fabricator.
Many top systems now offer 15–20 mm sight-lines. Some heritage models go as low as 14 mm in depth.
No. Frames made with duranium or similar alloys are up to 40% stronger.
Absolutely. With thermal breaks and triple glazing, they meet or exceed modern energy codes.
Up to 3 m high sliding panels or 2.3 m tall tilt-turn sashes are possible.
Usually yes. But they offer superior style, strength, and long-term value.
