Citi Homes Windows

Patio glass doors

The back of the house is where most of our work happens. A patio glass door is usually the starting point – replacing an old double-glazed slider, opening up a kitchen extension, or fitting a new rear access door that actually performs in a London climate.

Most people know roughly what they want when they start looking: more light, a clear view of the garden, a door that opens smoothly and does not cause problems in ten years. The Patio glass patio doors may be the answer you’ve been looking for.

What is a patio door?

Bifold doors

A patio door is a large glazed door designed to give access between the house and an outdoor space – a garden, terrace, decking, or side return. The term covers several door types, but in the UK it most commonly refers to a sliding patio door – a system with two or more large glass panels running on a track, where one or more panels slide horizontally to open.

The other door types frequently described as patio doors are French doors (two hinged leaves opening outward from the centre) and bifold doors (multiple panels that fold back like a concertina). All three are glazed rear access doors and serve the same broad purpose, but they work differently and suit different openings and property types.

Types of patio glass doors

The most widely installed type in the UK. Panels run on a top and bottom track. One panel is typically fixed; the other slides behind it to open. On modern aluminium systems, two, three or four panels can all be made to move. Sliding patio doors suit openings from around 1.5 metres up to 6 metres wide, need no swing clearance and give maximum glass area when closed.

Two hinged glazed panels opening outward from a central meeting rail. Suit narrower openings up to around 2.5 metres. Works well on period properties, Victorian terraces, and rear elevations where a hinged door is the natural choice.

Multiple panels that fold back in sections to open up to 90% of the frame width. Suited to wider openings – typically 2.5 metres and above. The right choice when maximum summer aperture is the priority.

What makes a good patio glass door?

A good patio door does four things well: it lets in light, it keeps heat in, it keeps intruders out, and it opens and closes smoothly for the life of the door. Here is how modern aluminium systems achieve that.

  • Thermally broken aluminium frames

    A polyamide strip separates the inner and outer aluminium sections. Cold cannot transfer through the frame. The interior face stays warm. No condensation on the profiles.

  • Double or triple glazing

    Double glazing is standard and meets current Part L building regulations. Triple glazing is available on all premium systems and worth specifying for north-facing openings or properties on busy roads.

  • PAS 24 security

    Multipoint locking, shoot bolts and Secured by Design compatible hardware as standard. The same security standard used on composite front doors and aluminium entrance doors.

  • Smooth operation

    Modern lift-and-slide mechanisms and precision roller systems make even large, heavy patio door panels easy to open with one hand. Quality hardware lasts decades without adjustment.

  • Low or flush thresholds

    A low-profile aluminium threshold is standard. Flush-fit options are available where the subfloor allows. Part M compliant thresholds on new build and extension work.

  • Bespoke sizing

    Aluminium bifold doors can be made to almost any size. Most systems handle panel widths up to 1,200mm and heights up to 3,000mm.

The brands we work with

Aluminium patio door systems

  • Smart Visofold 1000 - the UK's best-selling aluminium bifold doors

    The Smart Visofold 1000 is arguably the best-selling bifold door in the UK. Widely available, tried and tested, it offers a reliable aluminium bifold at a sensible price point. Thermally broken, PAS 24 certified, and available in a wide range of colours including woodgrain and the Smarts Sensations textured range. Updated for 2025 with slimmer profiles and improved hardware. A solid, dependable system for most residential openings.

  • Origin aluminium bifold doors - UK-made, 20-year guarantee

    Origin makes their bifold doors entirely in the UK and backs them with a 20-year product guarantee. Available in over 150 powder-coat colours. The OB-49 and contemporary range offer sightlines from around 92mm with chamfered or square-line profiles. Origin bifold doors sit alongside their sliding doors, french doors and aluminium entrance doors - making them a strong choice if you want one consistent system across the whole rear elevation.

  • Cortizo COR Vision - slimline aluminium sliding doors

    Cortizo COR Vision - the slimmest sightline on the UK market at 20mm. Panels up to 3 metres high. PAS 24 certified. Dual colour available. Popular on London extensions where near-frameless glass is the brief.

  • ALUK aluminium French doors - slim and high-performing

    ALUK French doors combine slim profiles with strong thermal performance. Available in double and triple glazed configurations, PAS 24 certified, and produced in a wide range of bespoke colours and sizes.

  • Reynaers CP 130 - premium aluminium sliding patio doors

    Reynaers CP 130 - handles panels up to 300kg. Open corner option available — two panels meeting at 90 degrees with no post. U-value from 1.5 W/m²K. Secured by Design approved. One of the most specified premium sliding systems in the UK.

Patio door colours and configurations

Panels

Two, three, or four panels. Two-panel suits most standard openings. Three and four panel configurations suit wider openings and kitchen extensions.

Any RAL or BS colour in gloss, matt or textured powder-coat. Anthracite grey, black and white are the most popular in London right now. Dual-colour — different inside and out — is available on most systems.

The Reynaers CP 130 and select Cortizo configurations allow two panels to meet at an external corner with no structural post.

Double glazing as standard. Triple glazing available on all premium systems. Acoustic glazing for road-facing or urban openings. Solar control glazing for south and west-facing doors.

Low-profile aluminium threshold as standard. Flush-fit where the subfloor allows. Part M compliant on new build and extension work.

FAQ

A patio door is a large glazed door giving access between the house and an outdoor space. The term most commonly refers to a sliding patio door in the UK — two or more glass panels running on a track — but also covers French doors and bifold doors used in the same position.

In practice, they are often the same thing. A sliding patio door is the most common type of patio door in the UK - large glass panels that slide on a track to open. The terms are used interchangeably by most homeowners and installers.

"Patio door" describes where a door is used. "French door" describes the style. A French door fitted at the back of the house is a patio door in the French style. A sliding patio door is a different style of the same thing.

Aluminium patio doors have slimmer frames, last considerably longer, hold their colour without fading and can be made to larger sizes. uPVC costs less upfront and suits standard-sized openings on a tighter budget. For most London homes, aluminium is the better long-term choice.

 

Yes. All systems we install are PAS 24 certified with multipoint locking, anti-lift devices and Secured by Design compatible hardware as standard.

Yes. Triple glazing is available on all premium aluminium systems including Schüco, Reynaers, ALUK and Origin. Worth specifying for north-facing, exposed or road-facing openings.

Most standard patio door installations take one day. Larger configurations or structural work may take two to three days.