How Wide Can Sliding Doors be?

Our advanced GS25 model, based on the Cortizo system, features sliding doors that can reach up to 4 metres wide and 4 metres high.  Choosing the width of your sliding doors isn’t just about the model’s maximum size; as a leading UK trade manufacturer of bespoke sliding doors, we explain this further in our guide.

What our Sliding Doors Sizes Guide Will Cover

Choosing the right width depends on many other factors in addition to your wish for the largest possible sliding doors, maximum glass and minimal amount of aluminium.  The location, structural requirements, sightline priorities, overall sliding sash weight, configuration, and your long-term servicing needs are also important.

This guide answers the most common questions about sliding door widths, including:

• The maximum and standard sliding door sizes available in the UK

• How to choose the right number of panels for your space

• Structural and installation factors for wide-span doors

• Real-world project examples using our GS15, GS20, GS25 and GS47 systems

Whether you're a homeowner planning a new extension or a trade professional comparing product options, this guide is designed to give you clarity before you specify or buy.

Maximum Sliding Door Dimensions UK

Modern aluminium sliding doors have come a long way. With the right system and engineering, it’s possible to achieve large-format panes of glass with minimal frames — ideal for views, light, and luxury design.

There are some other brands capable of doors up to around six metres high, with a maximum panel area of 15m2.  This is typically the maximum size you can get anywhere. However, these types of advanced sliding doors come with vast additional costs and considerations and only ever dealt with by specialist contractors.  This is why a typical maximum size of 4m x 4m high, makes a Glideline sliding door more accessible not just for professional installers but also for homeowners, architects and developers.

Here’s what’s possible with Glideline sliding doors:

Note: The actual opening width depends on the configuration and whether a cornerless, pocket, or standard layout is used.

Structural considerations:

• Larger panels = heavier sashes. Some sashes weigh over 400kg.

• Site access and lifting equipment may be needed for handling and installation.

• Wide-span doors require steel or reinforced lintels to support the load.

• Triple tracks can increase the available clear opening when using more panels.

• The more panels you have the thicker the track and frame head needs to be.

• The GS25 sliding door is designed for new build openings only.  GS15,GS20 and GS47 can replace dated sliding doors.

Track integration is also key.  If you desire a fully flush track on your sliding doors, this must be planned as part of the design.  This is also especially important for doors approaching or at their maximum sizes.

Standard vs Maximum Sizes

Most UK homeowners will install sliding doors between 2.4m and 3m wide as standard. These suit typical rear extensions, kitchen renovations, and modest refurbishments. They are also the typical sizes when replacing your dated patio doors.

When should you consider going to 4m+ or full-span?

• You have panoramic views or a large garden

• You are building a new extension and have more design freedom.

• You want fewer vertical mullions and larger glass areas

• You’re building a new home or major extension with generous apertures

• You want a luxury, frameless-style finish

Trade-offs when specifying larger doors:

• Weight:  Whilst engineering and good design makes large doors easy to move, remember you still operating in excess of 200-400 kg.

• Glass. Glass Thickness changes depending on the door sizes, for safety, protection from wind forces and external weather conditions.

• Cost: Price per panel rises with size due to materials, glass spec, installation and transport.

• Structure: Openings over 3.5–4m will need structural engineers and specific calculations.

• Thicker vertical profiles. Safety comes before sightlines.  Doors in exposed locations and at the largest sizes may need larger profiles to be safe, secure and reliable.

• The location of your doors is important.  A set of sliding doors on an exposed coastal location will have greater demands than the same set of doors on an extension a town or village.

Maximum size should always be matched with realistic expectations for usability, access, and service. 

Consider using a trusted and reliable installer who can support your doors even when the warranty expires.

Our entire sliding doors collection is easy to open and close, thanks to its advanced design and rollers. However, a 420kg door is still a considerable weight to bear in mind if you have children or elderly people who may use the doors.

How Many Panels Should You Have?

The number of panels determines how much of your opening you can actually slide open — and how the doors stack when open.

Note: Opening size also depends on track system (double vs triple).

You can also configure the doors so that you can choose which panels open. For example, on our two and three panel models the left and right panel can be opened.

Structural Requirements for Large Sliding Doors

When pushing the boundaries of size, your structure must be ready to handle the demands.

Lintels and headers
A wider opening requires a structurally sound lintel (typically steel) above. For bonded or very heavy doors, your builder may need to install a bespoke steel or box frame.

Foundations and floor finishes:
Ensure your sub-floor and foundations can support large panel weight. This matters most with flush threshold installations.

Planning and regs

For new build and extension projects, building control may want to see structural calculations for wide spans. Approved Document M and BS8300 may also apply if you're incorporating accessible thresholds.

When to involve a structural engineer:

• Openings over 4 metres

• Open corner sliding doors

• Doors installed beneath load-bearing walls

We always recommend involving Glideline at the early design stage. Our team can guide both the installer and structural engineer. 

Cost Implications of Door Width

Sliding door pricing scales with size — but not always proportionally.

Indicative cost differences:

• A 3m sliding door with standard glass and two panels might cost [£4,000–£7,500]

• A 4m wide version with larger panels and bonded glass could reach [£8,500–£14,900+]

Installation costs also vary, especially for:

• Glass handling and lifting equipment

• Wide-span thresholds or complex floor detailing

• Access and transport logistics

• Extra personnel needed

Need an accurate quote?
Get in touch with Glideline or your approved installer with your desired width and configuration, and we’ll provide an exact price for your setup.

Planning & Design Considerations

Room size matters. Oversized doors in a small room can dominate. Use the following as a rough guide:

• 3m doors for rooms under 5m wide

• 4m+ for open-plan kitchens and larger extensions

• Corner or 6m+ for grand designs and full-width openings

Other considerations:

• Panel stacking. Where do the panels go when open to plan kitchen units or furniture

• Opening direction: Left, right, centre-parting as this affects your overall clear opening

• Traffic flow: Consider internal/external paths and outdoor steps

• Solar Gain. The more glass you have, the greater the risk of rooms overheating. 

• Keeping the tracks clean to avoid opening and closing problems.

A well-sized door should feel integrated, not imposed. Whilst all-glass walls do look very impressive, also consider living with large glass doors.  Glass cleaning, solar gain, possible overheating rooms. These factors and others should be discussed with a professional door manufacturer and installer. 

Sliding Door Types & Maximum Widths

Modern sliding doors now come in all sorts of opening options whilst still accommodating large and maximum sizes of up to 4metres.

Note: Pocket fixed, and open-corner doors need careful structural design.

Browse our product pages for more on:

• GS15 Ultra Slim Sliding Door, with the slimmest mullion and surround frame in the UK and suitable for replacement or new build projects.

• GS20 Structurally Bonded Door, our most popular meeting most replacement and new build requirements, and the desirable 20mm central mullion.

• GS25 For the largest sizes. New build openings only and a 25mm central mullion, manual or automatic operation.  

• GS47 Beaded Sliding Door. Our entry-level product with outstanding overall specifications and a pleasing slim sightline all round.

Real Project Examples 

At Glideline, we’ve helped our customers complete numerous installations using our sliding doors collection. One of our most recent was our sliding doors in an impressive London Location, alongside other products in our range.

Contact us for more examples of what is possible with Glideline sliding doors and how we support our specialist network of sliding door installers. 

FAQs About Sliding Door Sizes

Can you have sliding doors wider than 4m per panel?
Yes, there are doors that will go up to about 6m high. Typically, the maximum overall area per panel does not exceed 15m2.  For this reason, 4m is the practical and safe limit due to sash weight and wind loading.

Do wider doors cost proportionally more?
Costs rise, but not always linearly. Larger glass, heavier frames and install complexity all add to the total price.  Other costs include special colours, solar control or enhanced security glazing, integrated floor tracks and installation location.

What’s the weight limit per sash?
Our doors start at about 200kg for the GS47 maximum going up to over 400kg for the GS25.

Do I need special glass for large panels?
All doors come with safety glass as standard.  The larger the door set, the level of acoustic or solar protection can also use laminated, toughened, or both.

Can I retrofit large doors into existing walls?
Our GS47, GS20 and GS15 are all designed for existing openings and can replace dated sliding doors. GS25 is intended for new build openings only.

Choosing the Right Size Sliding Doors

Before you decide, ask yourself or a professional door installer.

• What width do I want when the doors are open?

• Do I prefer fewer panels or more flexibility?

• Can my structure support the weight and span?

• What is my furniture layout and traffic flow?

• Are these the only doors out to my garden or outside space?

Talk to us before you buy. We’ll help you choose the right Glideline system and configuration for your exact needs. 

Choosing the finest sliding doors by Glideline – Contact us Today.

Sliding doors can reach up to 4000mm wide per panel, giving you unmatched views, daylight, and connection to the outdoors. Whether you're planning a modest kitchen renovation or a Grand Designs-style extension, sizing your sliding doors correctly is key to the success of your project.

Design your sliding doors with Glideline — the trade-only manufacturer trusted by professionals across the UK. Get in touch for product guidance, size-specific pricing, or technical support.