GS20 Sliding Doors Review

GS20 Sliding Doors | Ultra-Slim Aluminium by Fenestration Network

GS20 Sliding Doors | Ultra-Slim Aluminium Review

GS20 Sliding Doors – Ultra-Slim Frames, Maximum Impact

GS20 Sliding doors are a very special sliding door brand, based on the established Cortizo system and profiles. But that is where the similarity ends. GS20 sliding doors are enhanced, re-engineered and use upgraded components. The result is a sliding door that is better made, with higher performance, unique features, longer-term reliability and one that you can rely on long into the future.

We’ve created this guide to the GS20 sliding doors to help you understand the product better and help you see the benefits it can provide in your property renovation project.

Why Choose GS20 Sliding Doors?

The GS20 is a premium aluminium sliding system developed exclusively in the UK and only made by one manufacturer. At its heart are the tried and tested Cortizo profiles and design, one of the best in the UK for structurally bonded sliding doors.

This particular version of Cortizo is enhanced. Better hardware, more advanced manufacturing, meticulous attention to detail, incredible product quality. It even comes with a flush stacking option not available anywhere else on a similar door and even horizontal sliding windows for contemporary homes, matching the patio doors.

At the heart of the GS20 is the 20mm interlock– the slim central frame where panels meet. This gives you:

· More glass and less frame for uninterrupted views.

· Bright, open interiors filled with natural light.

· A sleek, contemporary look that enhances any style of property.

Unlike standard patio doors, GS20 is purpose-designed as an architectural-grade system. It’s as much about performance as it is about design.

GS20 sliding doors were also one of the first to engineer a full sealing system at the track as well as make this sliding door possible with a completely flush track with seamless internal flooring to external patio slabs or decking. It’s exceptional in its design.

GS20 sliding doors are available from two up to six panels, with fixed or open corners and is a perfect replacement for your older doors or for your new build home or extension.

Bigger Panels, More Possibilities

GS20 is built to handle large panel sizes with ease:

· Up to 2.5m wide and 3m high per panel

· Up to six sashes available

· Corner and open-corner options for dramatic architectural designs

· Flush stacking – panels slide neatly together, maximising the opening

Whether you’re replacing dated sliders or designing a new extension, GS20 gives you the flexibility to create anything from a two-panel door to a full wall of glass.

Effortless Everyday Use

Slim doesn’t mean fragile. Each GS20 door is engineered for durability and day-to-day reliability:

· Smooth, near-silent rollers make even the largest panels easy to slide.

· Flush threshold options provide step-free access to your garden or patio.

· Strong, thermally broken aluminium frames for energy efficiency and stability.

· High performance glass up to 30mm thick, with options for solar control or acoustic protection up to 41dB.

It’s a system designed not only to look spectacular but also to perform effortlessly in real homes.

Proven Security and Weather Protection

Large glass doors must keep your home safe and comfortable. GS20 delivers:

· PAS 24 level security with robust locking systems.

· Thermal efficiency with U-values from 1.3 W/m²K.

· Air, water and wind resistance tested to high European standards (Class 4, 7A and C5).

That means confidence in year-round performance, whatever the weather. The GS20 is only available as a double glazed door, but with the right glass specification it can comfortably meet or exceed current Building Regulations.

Premium Finishes and Hardware

The GS20 doesn’t just excel in performance – it’s designed to look and feel premium:

· Over 150 RAL colours plus textured finishes.

· Split colour options for interior and exterior.

· Anodised finishes for coastal or exposed locations.

· Architectural-quality handles available in black, grey, silver, white, or custom finishes.

Every detail is carefully considered so the doors complement your home’s style inside and out. Even when it comes to the trickle vents required at the head of most doors, our partnership with the manufacturer can locate the trickle vents elsewhere keeping the head of the doors as minimal as the sides with no additional add-on frame or visible trickle vent at the head.

Why GS20 Is a Smarter Long Term Choice

The Cortizo sliding door system is now one of the most popular bonded sliding doors in the UK. But with every popular product comes widespread availability.

Whilst a popular sliding door is good for keeping prices low, there are things to consider besides the lowest price.

Cortizo sliding doors are a highly engineered and complex door. They are not suitable for DIY installation and a professional installation is always recommended.

With many bonded doors, there is no support when out of warranty doors need servicing and repair. Every detail of GS20 doors is retained by the manufacturer so any repair, warranty or even new glass and doors are available to replace as fast as possible. Where other suppliers of bonded sliding doors will be unable to support the product in the future or resort to removing doors from your home and boarding up, GS20 sliding doors are more likely to be serviced and repaired. This is impressive peace of mind in your forever home.

With GS20, you’re investing in a sliding system that combines the slim profiles of premium European brands with the quality, reliability, and service of a UK manufacturer.

Talk to Fenestration Network About GS20 Sliding Doors

At Fenestration Network, we work with trusted installers nationwide to supply and fit the GS20 sliding door system and all are trained in this specialist sliding doors.

If you’re looking for a slimline aluminium sliding door that combines design impact with proven performance, the GS20 is one of the finest and reliable long-term choices on the market today.

Get in touch with us to find out more, arrange a showroom visit, or request a tailored quotation for your home.

The Fenestration Network White Glove Service

Our White Glove Service is our promise to take care of everything for you. From the moment you choose your windows or doors, we handle the process end-to-end — product advice, survey, installation, and aftercare.

You benefit from the reassurance of national expertise backed by local installers who know your area.

Every detail is managed with precision, ensuring your new doors and windows are fitted to the highest standard, fully compliant, and supported long after installation.

It’s a complete service designed to give you confidence, convenience, and total peace of mind.