Standard two-track slider
Two sashes on two tracks, either both sliding or one fixed. The workhorse for apartments, kitchens and dormitories; opens about half the width.
Window systems
Aluminium Sliding Windows
An aluminium sliding window has sashes that move sideways on tracks inside an extruded frame, so nothing swings into the room or out over a walkway. It is simple, economical, easy to fit with insect screens and well suited to apartments, hotels, schools and kitchens. Metline supplies sliding window profiles in 6063 and 6060, thermal-break sections and hardware to window fabricators and project buyers worldwide.
- Profile alloy
- 6063-T5 / T6, 6060-T66
- Tracks
- 2-track, 3-track, multi-track
- Wall thickness
- About 1.4 – 2.0 mm
- Typical Uw
- About 1.6 – 2.0 W/m²K (thermal break, Low-E)
What is an aluminium sliding window?
A sliding window (a horizontal slider) consists of an outer frame with two or more parallel tracks and sashes that roll on nylon or stainless rollers in the sill track. Where two sashes overlap, interlocking profiles hook together to resist wind and keep out rain. Because the sashes stay within the frame depth, sliders are the natural choice wherever an opening sash would hit furniture, curtains, a balcony railing or people walking outside.
Sliders are the most widely used window type in much of South and South-East Asia, the Middle East, Africa and Latin America, and remain common in North American and Australian housing. The reasons are practical: simple hardware, low cost, easy cleaning of inner sashes, straightforward insect screens on an extra track and wide horizontal openings that suit modern façades.
Their weakness is sealing. A sliding sash cannot be pressed onto a compression gasket the way a casement or tilt-turn sash is, so it relies on brush pile, fins and drainage. Well-designed modern systems close much of the gap with deeper interlocks, multiple seal lines and pressure-equalised sills, but in very exposed, windy or cold locations a casement window still seals better. Choosing well means matching the slider to the building, not using it everywhere.
Types of aluminium sliding window
Three-track slider
Either three glass sashes for a wider opening, or two glass sashes plus an insect screen on the third track. Common in Indian, Gulf and South-East Asian housing.
Thermally broken slider
Polyamide strips separate inner and outer aluminium, combined with Low-E insulating glass and extra seals for energy-efficient buildings and air-conditioned interiors.
Slider with integrated screen
A fly screen on its own track, as a pleated screen or as a separate fixed or sliding screen. See window screens.
Slim-frame and large-glass slider
Narrow sightlines and heavier sashes for floor-to-ceiling glazing, using stiffer interlocks and higher-capacity rollers. See slimline windows.
Fixed + sliding combinations
Sliding sashes combined with fixed lights, transoms or awning vents above, to balance daylight, ventilation and cost.
Reference specifications
| Item | Typical options | Notes |
|---|---|---|
| Alloy and temper | 6063-T5, 6063-T6, 6060-T66 | ASTM B221 / EN 755-2; T6 or T66 where higher strength is needed |
| Structure | Non-thermal or thermally broken | Polyamide break 14 – 24 mm typical |
| Profile wall thickness | 1.2 – 2.0 mm | Many specifications require 1.4 mm minimum on main frames |
| Frame depth | About 50 – 115 mm | Grows with number of tracks and glass thickness |
| Tracks and sashes | 2-track, 3-track, multi-track; 2, 3 or 4 sashes | Screen can occupy one track |
| Glass | Single 5 – 6 mm, double 5 + 12 + 5 or 6 + 12 + 6 mm, triple on request | Toughened or laminated where codes require |
| Rollers | Nylon, POM or stainless steel; single or tandem | Adjustable for height |
| Seals | Siliconised wool pile with fin, EPDM glazing gaskets | Weather strip on interlock and sash edges |
| Finish | Powder coat (AAMA 2603/2604/2605, Qualicoat), anodising (ISO 7599, Qualanod), PVDF, wood-grain | White, black, grey, champagne, bronze, any RAL |
| Performance | Basic non-thermal slider | Thermally broken premium slider |
|---|---|---|
| Air permeability (EN 12207) | Class 1 – 2 | Class 3 – 4 |
| Water tightness (EN 12208) | Class 2A – 4A | Class 5A – 8A |
| Wind resistance (EN 12210) | Class A2 – B3 | Class B3 – C5 |
| Whole-window Uw | About 4.5 – 6 W/m²K (single glass) | About 1.6 – 2.0 W/m²K (Low-E double) |
| Acoustic reduction | About 20 – 26 dB | About 30 – 35 dB with laminated glass |
Ranges are indicative of what systems in each group typically achieve in tests. Ask for the test report covering your window type and size; sliders larger than the tested specimen may perform worse.
Tracks, rollers, interlocks and drainage
Sill track and rollers
The sill carries all sash weight. A stainless or aluminium running rail and adjustable rollers give smooth movement; rollers must be rated for the glass weight, which is about 2.5 kg/m² per mm of glass.
Interlock
Where sashes meet, hooked interlock profiles join them when closed. Their depth controls wind deflection and rattle; tall windows need deeper or reinforced interlocks.
Anti-lift blocks
Blocks fitted in the head stop a closed sash from being lifted out of its track from outside, an important and cheap security detail.
Drainage
Water that passes the outer brush is collected in the sill and released through weep slots with baffles or flap valves. A raised inner sill upstand keeps it from blowing inward.
Sealing
Fin-seal pile on the sash edges and interlocks, gaskets around the glass and sealed frame corners. Corner joints are a frequent leak path and should be sealed during assembly.
Locking
Crescent locks for basic windows; hook or multi-point locks for security and better seal pull-in on large sashes. Opening restrictors limit opening width on upper floors.
Alloys and profiles for sliding windows
Window profiles are extruded almost entirely from the soft 6xxx alloys 6063 and 6060. Both extrude at high speed through complex hollow dies, give a smooth surface for anodising or powder coating and reach adequate strength after ageing. In a window the governing design check is usually deflection of the interlock and mullions under wind load, so section depth and wall thickness matter more than the small strength differences between tempers.
| Alloy / temper | Min. tensile Rm | Min. yield Rp0.2 | Typical use |
|---|---|---|---|
| 6060-T5 | 160 MPa | 120 MPa | Light sections, European systems |
| 6060-T66 | 215 MPa | 160 MPa | Main frames in European systems |
| 6063-T5 | 175 MPa | 130 MPa | Most frames and sashes worldwide |
| 6063-T6 | 215 MPa | 170 MPa | Interlocks, mullions, larger windows |
Minimum values per EN 755-2 for thin-walled profiles (up to about 3 mm wall); ASTM B221 limits for 6063 are slightly lower in T5. Check the mill certificate for the profiles supplied.
For details of the extrusions themselves, see 6063 extrusions and our window profile guide.
Sliding windows or casement windows?
| Factor | Sliding windows are better for | Casement windows are better for |
|---|---|---|
| Space | Balconies, kitchens, corridors where no swing space exists | Rooms where a sash can open inward or outward |
| Opening shape | Wide, horizontal openings and continuous bands | Tall or square openings |
| Ventilation | Up to about 50 % (2-track) or 67 % (3-track) of the area | Close to 100 % of the sash area; catches side breezes |
| Sealing | Brush pile and drainage; moderate air and water tightness | Compression gaskets and multi-point locks; higher tightness |
| Climate | Warm and humid climates, sheltered elevations | Cold, windy and rainy climates, high-rise exposures |
| Screens | Easy, on an extra track | Need inward-opening sash or retractable screens |
| Cost | Lower, simpler hardware | Higher |
A sensible approach on many projects is mixed: casement or tilt-turn windows on exposed, windward upper floors and bedrooms that need high sealing, and sliders on balconies, kitchens and sheltered elevations. See casement window systems.
Standards and safety rules
| Topic | Standard or rule | Notes |
|---|---|---|
| Product performance (Europe, UK) | EN 14351-1 with EN 12207/12208/12210 | CE / UKCA marking |
| Product performance (North America) | AAMA/WDMA/CSA 101/I.S.2/A440 (NAFS) | Horizontal sliders are rated by class (R, LC, CW, AW) and performance grade |
| Energy labels | NFRC 100/200, EN ISO 10077 | U-factor and solar heat gain |
| Australia | AS 2047, AS 1288 (glass) | Wind and water ratings, glass selection |
| India | IS 1948 (aluminium doors, windows and ventilators), NBC 2016 | Profile and fabrication requirements |
| Emergency escape (US IRC) | Net clear opening at least 5.7 ft² (5.0 ft² at grade floor), 24 in high, 20 in wide, sill at most 44 in above floor | A slider opens only half its width, so check it meets egress in bedrooms |
| Fall protection (US IRC) | Sill under 24 in above floor and more than 72 in above grade needs an opening control device or a 4 in opening limit | Fit restrictors on upper floors |
Where aluminium sliding windows are used
- Apartment and housing developments: repeated two- or three-track sliders built to a window schedule, delivered labelled by flat and floor.
- Balconies and kitchens: sliders that save space and integrate fly screens and grilles.
- Hotels, schools and dormitories: many identical windows with restrictors, acoustic glass on road-facing sides and simple, replaceable rollers.
- Commercial and mixed-use buildings: sliders in offices, shops and service buildings, often combined with fixed lights.
- Coastal and humid regions: powder coat with seaside pre-treatment, stainless hardware and generous drainage.
RFQ checklist and supply
- Project dataCountry, city, building type and height, so wind, climate and code requirements are known.
- Window scheduleWindow marks, sizes, quantities, track count, sash arrangement and installation position.
- Glass and hardwareSingle, insulating, Low-E, toughened, laminated or acoustic glass; rollers, locks, restrictors or a specified brand.
- Finish and performancePowder coat, anodising, PVDF or wood-grain colour; air, water, wind, thermal and acoustic targets.
- Packing and deliveryProtective film, labelling by location, export cases or containers on EXW, FOB, CIF or DAP terms; EN 10204 3.1 certificates for the profiles.
A quotation can start from an outline schedule without full drawings; profile sections and glass are then confirmed during shop-drawing review.
References and standards
- EN 14351-1 – Windows and doors: product standard, performance characteristics
- AAMA/WDMA/CSA 101/I.S.2/A440 – North American Fenestration Standard
- International Code Council – International Residential Code, sections R310 (emergency escape) and R312 (window fall protection)
- EN 755-2 – Extruded rod/bar, tube and profiles: mechanical properties
- IS 1948 – Aluminium doors, windows and ventilators (Bureau of Indian Standards)
Aluminium (aluminum) sliding windows: FAQ
Are aluminium sliding windows good for apartments and hotels?
Yes. They save space, cost less than casements, take insect screens easily and use simple, replaceable hardware, which suits large numbers of identical windows. On exposed high floors, check that the chosen system has tested air, water and wind classes suitable for the height.
Do sliding windows leak more than casement windows?
They generally achieve lower air and water tightness because the sash cannot compress a gasket. A well-designed slider with deep interlocks, fin-seal pile and a drained, raised sill performs well in most climates; for very exposed or cold locations, casement or tilt-turn windows are better.
Two-track or three-track: which should I choose?
Two-track for most openings. Choose three-track when you need a wider opening or want a fly screen on its own track behind two glass sashes, as is common in hot, humid regions.
Can aluminum sliding windows be soundproof?
They can be improved considerably with laminated acoustic glass, better seals and a thermally broken frame, reaching around 30 – 35 dB. For heavy traffic, rail or airport noise, a dedicated acoustic window with compression seals is more effective.
Which alloy is used for sliding window profiles?
6063-T5 is used for most frames and sashes worldwide; 6063-T6 or 6060-T66 for interlocks and larger windows where more strength is needed.
Can I get a quote without full drawings?
Yes. A window schedule with sizes, quantities, type, glass and finish is enough for a first quotation; details are confirmed during shop-drawing approval.
Need sliding windows for a project?
Send your window schedule, glazing and finish requirements to sales@metline.in. We will return a profile proposal and a delivered price.
