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keller minimal windows

Slim Framed Sliding Glass Doors

The Keller minimal windows system from IQ Glass is a high end sliding glass door system, suitable for projects where the slimmest framing finish is required in floor-to-ceiling sliding glass doors. These aluminium sliding glass doors sit harmoniously side by side with an extremely slender vertical frame of only 21mm between glass panels.

All the surrounding frameworks of the Keller minimal windows can be hidden in the building surround with the floor track finished flush with the floor both internally and externally.

Available in both a double glazed (minimal windows) or triple glazed sliding door system (minimal windows 4+) these large format keller sliding doors can hold units of glass up to 12m2 in a moving panel.

But the external beauty and striking aesthetics of these slim framed sliding glass doors are only a small part of their genius.

The advanced engineering that has gone into designing this exclusive aluminium framing system means that not only do the frames conform to the highest specifications of architectural glazing but also far surpass the practical and efficiency targets that modern design and building needs.

Floor-to-Ceiling Sliding Glass Doors

The thermally broken aluminium frame can achieve Uw values of 1.4 W/m2K in the double glazed minimal window system, the Keller minimal windows 4+ tripled glazed sliding glass doors can achieve a Uw value of as little as 0.8 W/m2K!

The minimalistic framing solution has been fully tested at the prestigious Rosenheim Institute in Germany for Security, Air Permeability, Water Resistance and Resistance to Wind Load achieving fantastic results for such a slim framed system.

Below each sliding glass door system, a solid neoprene base supports the aluminium sliding frames, creating a solid continuous base to fix to and acting as a drainage base to the framing. IQ Glass can detail our flush threshold drainage channel to be used in conjunction with the minimal windows.

These slim framed Keller sliding glass doors are also extremely flexible and are able to be used in multiple configurations with almost no restriction on the number of panes with opening corners, pocket doors and integrated Juliet Balconies, always with the option for automation if necessary.

keller minimal windows sliding glass doors
Keller minimal windows UK Exclusive to IQ Glass

Grand Designs Sliding Doors

The minimal windows system is an award-winning architectural glazing solution.

It has been used widely on some of the most prestigious and exciting architectural projects throughout the UK and abroad, contributing towards award-winning architectural designs.

White Lodge in Oxted featured these floor-to-ceiling sliding glass doors throughout the new build home and won the coveted Home of the Year from the Sunday Times. Other projects, including Dalston House and Sweethaws, have both been recognised for their use of our slim framed sliding glass doors. You can see more of our award-winning projects here

IQ Glass glazing and these slim framed sliding glass doors are frequently seen in the glossy pages of design magazines and on high design TV programs such as Grand Designs. Both Russell Garden Mews and the Rusty House project have both being featured on this program and use minimal windows.

You can view our Media Mentions here at IQ in the Media.


minimal windows at the Showroom

Come and visit the IQ Glass showroom in Amersham to see the minimal windows sliding doors in person.

Our large Keller minimal windows box showcases three sets of Keller minimal windows acting as the external envelope of this standalone space.

A two-track and three track minimal window sliding effortlessly away from a 90-degree corner connection, allowing you to see all of these elements in real life.

To the rear of the standalone glass box is a single sliding pocket door with an external key lock, again showcasing even more design possibilities of the system.

Investigate the threshold details, base tracks, locking and ultra slim framing in person.

ASK US ABOUT OUR Minimal Windows Slim Framed Sliding Glass Doors



keller minimal windows open corner configuration

Opening Corners

Both the Keller minimal windows and the triple glazed Keller minimal windows 4+ are able to be designed into an opening corner sliding door configuration, with floor-to-ceiling sliding glass doors moving away from a corner connection with no framing left over.

These corner connections can be almost any degree required as well as inverted corners which are useful to create glass courtyard spaces.

When a cantilevered roof design is being considered you should ensure that your structure is designed with the maximum live load deflection tolerance for the Keller minimal windows in mind (+/-5mm).

When closed the corner framing box create a vertical frame of approximately 74mm wide depending on the connection angle.

Pocket Doors

If you want to create a fully open doorway or aperture you can design our Keller minimal windows and Keller minimal windows 4+ to slide away into a hidden cavity pockets within a wall.

These ‘pocket doors’ can be slid in and out of a cavity within the wall to create a fully open doorway. When closed our closing cap will block the entrance to the cavity to create a clean surrounding frame. Single Pocket Doors are also possible.

For each pane sliding into a single pocket, you will need to engineer the space for each track to sit within the wall. A single track sliding pocket door will need a cavity of at least 65mm, a two-track 125mm and so on.


keller minimal windows pocket doors
keller minimal windows juliet balcony

Juliet Balconies

Create minimally framed Juliet Balconies using our minimal windows and integrated frameless glass balustrades.

By fixing the glass balustrade into the depth of the sliding glass door frames you can create a clean and clear opening when the sliding doors are open or closed.

At IQ Glass we use toughened laminated structural glass balustrades, view the glass balustrades product page for more information about glass specification.

Without having to bolt glass to the external face of the building to create a Juliet Balcony you can create a much neater external façade design. Internally you do not interrupt any views or sightlines due to the frameless nature of the IQ Glass balustrades.

Base Options

There are two base track options for the Keller minimal windows system.

The Flush Track

A 38mm deep aluminium base frame, sat below the finished floor levels, with 12-13mm deep tracks. The resulting glass elevation has a full floor to ceiling glass finish/ 

The Freeway Base

A completely flat and flush base track from inside to out with no dips or regresses within the floor. The resulting glass elevation has approx 37mm frame visible above finished floor level.


IQ Glass have designed some unique base options available only to the Keller minimal windows and Keller minimal windows 4+ systems. We install a solid Neoprene base block beneath each installation of Keller minimal windows and Keller minimal windows 4+. This unique base detail creates a solid and continuous base for the slim aluminium framing to be installed onto and also acts as part of the drainage system for these slim framed Keller sliding glass doors.

Any water from the Keller sliding glass doors will drain through the base aluminium track and onto the neoprene block which has built-in water runoff grooves to drain the water outside and away. IQ Glass can also integrate our flush threshold drainage channel into the minimal windows installation for a flush external drainage solution.


minimal windows base by Keller UK Exclusive IQ Glass
keller minimal windows handle

Locking and Handles

The Keller minimal windows system has been tested to receive a security rating of WK2/RC2 for effective protection against burglar or vandalism. 

The two-point thrust lever locking mechanism of the Keller minimal windows is fully integrated into the 21mm vertical profile and only accessible from the inside of the building, making the locking mechanism virtually impossible to interfere with.

This two-point locking is activated via a trust lever handle applied to the side of a 21mm profile to maintain the minimal frames.

If external locking is required we can offer either an electrical locking solution or an external wall mounted key lock. We do not recommend Keller minimal windows be used as the main entrance door to a building or home.

Insect Screens, Ventilation & Automation

There are no trickle ventilation options with the minimal windows frames. We can offer a ventilation option called ‘Slot Aeration’ whereby you can lock the minimal windows in a slightly open position (20/40mm) which allows ventilation down the full length of the Keller sliding glass doors.

Automation is also available for the minimal windows sliding glass doors if necessary. We would only recommend automation if each sliding glass unit weighed over 500kg, any unit lighter than this should be able to be moved manually.

The Keller sliding glass doors installed at our showroom in Amersham are almost at the threshold before automation would be required so you would like to feel the movement of these large sliding glass doors please contact us to arrange a visit.

You can also integrate minimal sliding Insect Screens into a Keller minimal windows installation. These can either be installed on their own 60mm deep track, increasing your track depth by one, or thinner sliding panels of insect-proof mesh. Our insect screens allow light and ventilation whilst keeping the inside spaces free of insects and mosquitos.

keller minimal windows ventilation

Commercial use

keller minimal windows commercial application

Commercial Applications for minimal windows

Our Keller minimal windows sliding glass doors have a multitude of commercial applications to create large siding glass facades.

With the slim aluminium framing afforded to minimal windows, you can create striking glass facades using these slim sliding glass doors on all types of projects.

These minimally framed doors are often used on a wide range of interesting architectural projects such as luxury care homes, multi-unit residential developments and commercial buildings.

You can view our commercial project gallery to see more applications.

Due to the high levels of security and weather protection afforded to these high specification sliding glass facades they can be used on a wider range of projects than other similar products can be. The minimal framing compliments a detailed architectural design whilst the robust wind and rain projection means that these Keller sliding glass doors can be used on even the highest penthouse spaces.


Featured Project

A luxury residential development in London required a high quality sliding glass door system to be used as part of the façade material for the luxury flats they were creating.

Keller minimal windows 4+ were used on all floors of the Buckingham Gate development as the sliding balcony doors leading to a small projecting balcony for each upper floor flat.

The Keller minimal windows 4+ were utilised on the Penthouse apartment in a Juliet Balcony design with integrated frameless glass balustrade.

Down into the basement spaces, Keller minimal windows surrounded a deep light well that drew light into the sub ground level living spaces. With integrated balustrades within each opening, the basement flats were still able to draw in large amounts of natural light as well as natural ventilation all with a minimal and modern glass façade design.

You can see more images of this residential development at our project gallery.


keller minimal windows commercial


minimal windows

IQ GLASS DRAFT NBS - minimal windows

Typical Detail of Integrated Balustrade

minimal windows Drainage Diagram

minimal windows Premium Brochure


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