Two-track sliding door
One sliding and one fixed panel (or two sliders). The most common patio and balcony door: simple, economical and quick to specify. Opens about half the width.
Door systems
Aluminium Sliding Glass & Patio Doors
An aluminium sliding glass door, usually called a patio door, is a large glazed door whose panels slide sideways in an extruded aluminium frame to connect a room with a garden, terrace or balcony. The frame stays slim while carrying heavy insulating glass, and with a thermal break and Low-E glazing it meets modern energy rules. Metline supplies sliding patio door profiles, thermal-break sections, tracks and hardware to door fabricators for residential and commercial projects worldwide.
- Frame alloy
- 6063-T5 / T6
- Layouts
- 2-track to multi-track, pocket, corner
- Glass
- Toughened, laminated, Low-E IGU
- Typical Uw
- About 1.4 – 2.0 W/m²K (thermally broken)
What makes a good aluminium sliding glass door?
A patio door is mostly glass, often 80 – 90 % of its area, so buyers tend to judge it by the view. In service, however, its performance is decided by the parts you do not see: the stiffness of the interlock, the rollers and track, the drainage path under the sill, the gaskets and the thermal break. These decide whether the door still slides easily, stays dry in driving rain and keeps the room comfortable ten years after installation.
Aluminium is well suited to this because 6063 extrusions combine stiffness, accuracy and a durable finish in sections narrow enough to keep sightlines slim. A modern thermally broken aluminium patio door can carry triple glazing on sashes weighing a few hundred kilograms, which uPVC frames struggle to do without steel reinforcement and much wider profiles.
A complete patio door package contains the outer frame (head, sill and jambs), the sashes, the interlock profiles where the sashes meet, the bottom track and running rail, rollers, locks and handles, gaskets and brush seals, glazing beads and setting blocks, the glass itself and, often, an insect screen. Metline supplies the aluminium profiles, tracks and hardware to your drawings; your fabricator adds the glass, assembles and glazes the doors.
Types of sliding patio and glass door
Three-track patio door
Three panels on three tracks so two can stack behind the third, opening about two-thirds of the width. A good compromise between opening area and cost.
Multi-track / multi-slide door
Four to six panels on as many tracks, stacking to one side or parting in the middle. Used in villas, hotels and restaurants where most of the wall should open.
Pocket sliding glass door
Panels slide into a cavity in the wall and disappear, leaving the full opening clear. The wall must be designed for the pocket, with access to the concealed track and drainage.
Corner sliding door (90° or 135°)
Two runs meet at a corner without a post, so the whole corner opens. Needs careful structural design because the corner loses the post that would normally resist wind and roof loads.
Slim-frame sliding door
Very narrow interlocks and concealed frames for an almost frameless look. See slimline doors.
Motorised sliding door
An electric operator moves heavy sashes at the touch of a switch or remote, useful above about 300 kg and for accessible design.
Oversized custom door
Panels up to 3 m tall or more, sized to the project; glass weight, roller capacity and wind load are checked before quotation.
Lift-and-slide door
Sash lifts off its seals to move and clamps down to close, giving better sealing for large panels. See sliding door systems.
Typical technical specifications
These values describe the usual range of current thermally broken patio door systems; confirm the exact figures for the system and size you choose, since performance is tested on specific specimens.
| Item | Typical range | Notes |
|---|---|---|
| Profile alloy and temper | 6063-T5; 6063-T6 or 6061-T6 for heavy-duty parts | ASTM B221 / EN 755-2 |
| Main profile wall thickness | About 1.6 – 2.5 mm | Load-bearing walls usually 2.0 mm or more |
| Frame depth | About 86 – 200 mm | Deeper frames for three or more tracks and thicker glass |
| Sash depth | About 34 – 70 mm | Sets the maximum glass thickness |
| Thermal break | Polyamide 15 – 35 mm | Wider breaks give lower frame U-values |
| Glazing thickness | About 20 – 52 mm | Double or triple insulating units |
| Sash weight | 100 – 400 kg depending on hardware | Heavy panels use tandem or lift-and-slide rollers |
| Whole-door U-value | About 1.4 – 2.0 W/m²K | With Low-E argon-filled double glazing |
| Acoustic reduction | About 30 – 40 dB Rw | Laminated acoustic glass and good seals for the upper end |
| Finishes | Powder coat, anodised, PVDF, wood-grain | Dual colour (different inside and out) on thermally broken frames |
Common patio door sizes
Patio doors can be made to almost any opening, but in North America many residential openings follow nominal sizes in inches, and replacement doors are often ordered to them. The heights of 80 in (6 ft 8 in) and 96 in (8 ft) are the most common. Metric projects are normally made to measured openings.
| Nominal size (W × H) | Metric equivalent | Typical layout |
|---|---|---|
| 60 × 80 in | 1524 × 2032 mm | 2-panel, narrow patio or balcony |
| 72 × 80 in | 1829 × 2032 mm | 2-panel, the most common residential size |
| 96 × 80 in | 2438 × 2032 mm | 2-panel wide, or 3-panel |
| 120 × 80 in | 3048 × 2032 mm | 3- or 4-panel |
| 144 × 80 in | 3658 × 2032 mm | 4-panel multi-slide |
| 72 × 96 in | 1829 × 2438 mm | Tall 2-panel |
| 120 × 96 in | 3048 × 2438 mm | Tall 3- or 4-panel |
| 144 × 96 in | 3658 × 2438 mm | Large multi-slide |
Nominal sizes are close to the overall frame size, not the clear opening. Always measure the rough opening at several points and allow installation clearance.
Glass is the heaviest part of the door. Float glass weighs about 2.5 kg per square metre for every millimetre of thickness, so sash weight is easy to estimate. The table shows glass weight only; add roughly 10 – 20 % for the aluminium sash.
| Glass make-up | Total glass (mm) | Glass kg/m² | Glass in a 1.5 × 2.4 m sash (kg) |
|---|---|---|---|
| 5 + 12 + 5 mm double | 10 | 25 | 90 |
| 6 + 16 + 6 mm double | 12 | 30 | 108 |
| 6.38 lam + 16 + 6 mm double | 12.4 | 31 | 112 |
| 8 + 16 + 8 mm double | 16 | 40 | 144 |
| 5 + 12 + 5 + 12 + 5 mm triple | 15 | 38 | 135 |
| 10.76 lam + 16 + 8 mm double | 18.8 | 47 | 169 |
Choosing the glass
Toughened (tempered) glass
About four to five times stronger than annealed float glass and breaks into small blunt pieces. The minimum for doors under EN 12600, 16 CFR 1201 / ANSI Z97.1 and AS 1288.
Laminated glass
Two panes bonded with a PVB or ionoplast interlayer that holds fragments if broken. Adds security, cuts noise and blocks almost all UV, which protects floors and furniture from fading.
Low-E insulating glass
A thin metal oxide coating reflects long-wave heat. Use a high solar gain coating in cold climates and a solar-control (low SHGC) coating in hot ones.
Argon fill and warm edge
Argon in the cavity and a plastic or stainless "warm-edge" spacer reduce heat loss and condensation at the glass edge.
Triple glazing
Needed to reach very low U-values in cold climates; heavier, so check roller capacity and frame depth.
Decorative glass
Tinted, frosted, patterned or reeded glass for privacy in bathrooms, street-facing rooms and offices.
| Project condition | Recommended configuration |
|---|---|
| Hot, sunny climate | Thermally broken frame, solar-control Low-E glass with low SHGC, light frame colour |
| Cold climate | Wide thermal break, triple or argon double glazing, warm-edge spacers, high-performance seals |
| Coastal or humid site | Seaside pre-treatment with Qualicoat Class 2 powder, AAMA 2605 or anodising; stainless hardware |
| High wind or driving rain | Tested water tightness, drained sill, multi-point locks, verified wind load class |
| Busy road or airport | Laminated acoustic glass, high air-tightness class |
| Floor-to-ceiling and public areas | Toughened or laminated safety glass on both panes |
Construction details that separate good doors from poor ones
Stiff interlock
The meeting stiles carry wind load over the full door height. Deeper or reinforced interlocks stop the panels bowing and whistling in strong wind.
Drained sill
Water that passes the outer seals must drain out through weep slots and baffles, not into the floor. Concealed drainage keeps the sill neat.
Multiple seal lines
EPDM gaskets around the glass and fin-seal brush pile or gaskets at the interlock and sash edges limit air leakage, water ingress and dust.
Thermal break
Polyamide strips separate the inner and outer aluminium, reducing heat flow and preventing condensation on the inside frame in winter.
Adjustable rollers
Tandem stainless or sealed-bearing rollers that can be adjusted after installation keep the sash running true as the building settles.
Slim sightlines
Narrow frames and interlocks increase the glass area and daylight, but only if the profiles are stiff enough for the panel size.
Track and threshold options
| Option | Description | Best for |
|---|---|---|
| Raised sill track | A sill standing about 20 – 50 mm above the floor with an upstand behind the outer track | Exposed façades, high-rise, heavy rain |
| Low-profile track | Reduced step of around 15 – 20 mm with internal drainage | Most residential patios |
| Recessed / flush track | Track set into the floor so the threshold is level | Step-free access, indoor-outdoor living under a canopy |
| Thermally broken sill | Polyamide break in the sill itself | Cold climates where the sill would otherwise cause condensation |
| Multi-track sill | Three to six tracks in one frame | Large openings and stacker layouts |
A flush threshold looks clean and suits wheelchairs and pushchairs, but it moves the weather line to floor level. Use it where the door is sheltered by a canopy or recessed in the façade, provide a drainage channel outside, and expect a lower water-tightness rating than a raised sill.
Aluminium vs uPVC sliding patio doors
| Criterion | Aluminium (thermally broken) | uPVC |
|---|---|---|
| Stiffness and strength | High; suits large and heavy panels | Lower; steel reinforcement needed for larger sizes |
| Sightlines | Slim frames and interlocks | Wider frames and sashes |
| Maximum panel size | Large, 3 m tall or more with suitable hardware | Usually limited to standard residential sizes |
| Thermal performance | Good with thermal break and Low-E glass | Good inherently, frames insulate well |
| Heat and sunlight | Dimensionally stable; finish holds colour | Can soften or bow in strong sun, especially dark colours |
| Colours | Any RAL, anodised, wood-grain, dual colour | More limited range |
| Recyclability | Recycled repeatedly without loss of properties | Recyclable but less commonly reclaimed |
| Initial cost | Higher | Lower for standard sizes |
For a small standard balcony door on a tight budget, uPVC is a reasonable choice. For large openings, multi-track layouts, slim frames, strong sunlight or commercial use, aluminium is usually the better long-term option.
Replacing an existing sliding glass door
- MeasureWidth and height at three points and wall depth; use the smallest values and check that the opening is square.
- Inspect the sillLook for a damaged, corroded or blocked track and rot or water damage in the floor below; decide on raised, low or recessed track.
- Choose the layoutTwo, three or multi-panel, which panel slides, and from which side it is operated, viewed from outside.
- Select glassSafety glass in all cases, then thermal, solar and acoustic performance for the climate and location.
- Match hardwareRollers rated for the sash weight, locks, handles and screen.
- Install and testFix level and plumb, seal to the wall and floor membrane, then check smooth sliding, locking and even seal contact.
What to send for a patio door quotation
- Opening width × height and quantity for each door type
- Project country and city (for wind, climate and code requirements)
- Residential or commercial, new build or replacement
- Panel layout and opening direction
- Glass type and thickness, and any U-value, SHGC or acoustic target
- Frame colour and finish standard; hardware brand preference if any
- Drawings or photographs of the openings
Each order ships with EN 10204 3.1 mill certificates for the extrusions, coating-thickness records and a packing list. Profiles are supplied in full lengths or cut to size, with hardware boxed by door, export-packed on EXW, FOB, CIF or DAP terms.
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
- NFRC 100 / NFRC 200 – U-factor and solar heat gain coefficient rating procedures
- EN 12600 – Glass in building: pendulum impact test for safety glazing
- 16 CFR Part 1201 – Safety Standard for Architectural Glazing Materials (US CPSC)
- ASTM B221 – Aluminum and Aluminum-Alloy Extruded Bars, Rods, Wire, Profiles, and Tubes
Aluminium (aluminum) sliding glass doors: FAQ
Which is better, aluminium or uPVC sliding glass doors?
Aluminium is better for large panels, slim frames, multi-track layouts, hot climates and commercial use, because it is stiffer and dimensionally stable. uPVC costs less and insulates well in standard residential sizes. A thermally broken aluminium door with Low-E glass closes most of the thermal gap.
What are the disadvantages of aluminum patio doors?
Aluminium conducts heat, so frames without a thermal break lose heat and can show condensation in cold weather. The initial cost is higher than uPVC. Both points are addressed by choosing a thermally broken system with insulating glass.
What is the standard size of a sliding patio door?
In North America the most common sizes are 60, 72 and 96 inches wide by 80 inches high, with 96-inch tall doors increasingly popular. Metric projects are usually made to the measured opening.
How heavy is a sliding glass door panel?
Glass weighs about 2.5 kg/m² per mm. A 1.5 × 2.4 m sash with a 6 + 16 + 6 mm unit carries about 108 kg of glass, plus the frame. Larger or triple-glazed panels easily exceed 200 kg and need heavy-duty or lift-and-slide hardware.
Do sliding glass doors have to use safety glass?
Yes. Building codes require safety glazing in doors: toughened or laminated glass that passes EN 12600 in Europe, 16 CFR 1201 or ANSI Z97.1 in the US, or AS 1288 in Australia.
Can a sliding patio door have a flush threshold?
Yes, with a recessed track. It works best where the door is sheltered, with an external drainage channel, because a flush sill gives lower water tightness than a raised one.
What information do you need to quote?
Opening sizes and quantity, project location, layout and opening direction, glass and performance targets, frame colour and finish, hardware preference and any drawings or photos.
Choosing patio doors for a project?
Send opening sizes, layout, glass and finish to sales@metline.in. We will propose a profile series and a delivered price.
