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keller minimal windows

Award-winning Slim Framed Sliding Glass Doors

Where can I get minimal windows® from in the UK?

The minimal windows® sliding doors are exclusively available from IQ Glass in the UK. The beauty of this system is the frameless aesthetic that can be achieved through the completely flush base (which boasts a wheel track depth of 12-13mm) and the ability to hide the outer frames within the wall finishes, leaving only the slim horizontal sightlines visible.

These thermally broken sliding glass doors can hold up to 8.5m2 of glass per sliding pane with a maximum height of 4m. For manually opening sliding doors, each pane can weight up to 500kg however for any weight greater than this sliding doors will need to be automated. IQ has a broad range of options for automated sliding doors, including integrating the sliding doors into a home automation system.

There are various frame finishes and glass options available for the minimal windows® system. The frames can be finished in a Polyester Powder Coating (PPC) in any RAL colour - all RAL colours are available to view in the IQ Glass Showroom. For buildings that are within close proximity to the coastline, a marine-grade finish is also available to help prevent the frame from becoming weathered by salt carried in the air. There is a broad range of optional glass finishes and coatings such as solar control coatings, privacy glass, low iron glass and heated glass.

This modern glazing system boasts incredibly elegant thin vertical sightlines that offer uninterrupted views of the garden and surrounding landscape. The minimal windows® sliding doors offer a beautifully minimalistic frame aesthetic with a completely flush threshold and base detail. The frames which surround the outer edge of the sliding doors can be hidden within the wall finishes to accentuate the frameless aesthetic.

Using IQ's years of expertise, the minimal framing of the sliding patio doors is now also available as a vertically sliding guillotine window! The vertically sliding panes can be either manually operated with counterweights or automated with motors. When these windows slide open, the top pane slides down to meet the central pane and in the same motion the lower pane slides up to align with the central pane. Depending on the size of the opening, when the panes are in their open position they can act as a doorway to access the external living spaces. View more about this minimal windows® sliding doors adaptation here.

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® sliding door 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 design.

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 been recognised for their use of our slim framed sliding glass doors. You can see more of our award-winning projects here.

These slim framed sliding doors and glazing by IQ Glass are extremely popular in London and greater London, frequently seen in the glossy pages of design magazines and on popular TV programs including Grand Designs and Inside Out Homes. Russell Garden Mews and the Rusty House project, both with minimal windows® installations, were featured on Grand Designs.

IQ Glass often feature in the Media with projects that used Keller minimal windows® sliding doors. You can view all our Media Mentions here at IQ in the Media.


minimal windows sliding doors at the Showroom

Where can I see minimal windows® in person?

View the minimal windows sliding doors at the IQ Glass Showroom in Amersham, Buckinghamshire. Our large Keller minimal windows box showcases three sets of sliding doors forming two complete walls of sliding glass and a pocket door.

To the two front facades of the standalone glass box, a 2-track and a 3-track sliding door system slide effortlessly away from a 90-degree corner connection. To the rear corner of the space, there is a single sliding pocket door that slides into a pocket in the wall cavity to create a completely frameless aesthetic.

Visit the IQ Glass Showroom to see these sliding door configurations for yourself and explore the minimalistic threshold details, base tracks, locking and ultra-slim frame in person


keller minimal windows open corner configuration

Corner Opening Sliding Doors

The Keller minimal windows® sliding doors, including the triple glazing Keller minimal windows®+4 system, can be designed in a corner opening configuration, The floor-to-ceiling glass slides away from a corner point to open up two adjoining walls.

The corner opening configuration does not need to meet at an exact 90-degree angle. The sliding doors can meet at any angle between 65 degrees to 177 degrees to achieve a corner opening design for a broad range of architecture.

Corner-opening is not limited to one corner of a building's parameter, for buildings that are not simply square the sliding doors can follow the contours of the building; therefore 2,3,4 (and even more) corner-opening sliding doors can be installed one after the other to create a continuous stream of sliding glass doors.

Sliding doors are often designed and installed to slide internally or towards walls or pocket door systems. However, IQ is aware that there can be structural limitations that mean internal walls (such as load-bearing walls) cannot be removed and therefore a corner opening sliding door system wouldn't be possible. The Keller minimal windows® sliding doors can overcome this obstacle as the sliding doors can be designed to slide externally to reveal an open corner aesthetic.

This configuration works in a similar way to standard corner-opening sliding doors, however, in this instance, one side of the sliding doors will stack next to an internal wall (as usual) while the adjoining doors slide forwards past the corner join where they stack externally to the building. This creates the same finished aesthetic as traditional corner-opening sliding doors; the only difference is that one side of the system stacks externally.

Pocket Doors

The Keller minimal windows® sliding doors can be installed to slide into a pocket door system. This hides the sliding panes of glass, within a specially made cavity in the wall of a building, when the sliding doors are open. The resulting aesthetic is a beautifully frameless appearance that fully opens up a space.

The pocket door isn’t just for use on minimal windows® that slide along one straight base track, they can be used for corner opening configurations and even for single pane sliding glass used for doorways.

When the sliding doors are closed, the closing gap installed to one end of the sliding doors will block the entrance of the cavity to create a clean surrounding frame. When the sliding doors are open the frame of the sliding doors fill the cavity which creates a smooth finish to the face of the wall.

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 of 125mm and so on.

keller minimal windows pocket doors
keller minimal windows juliet balcony

Juliet Balconies

minimal windows® sliding doors can be used for openings that lead out onto a balcony or for Juliet Balconies. Installing these sliding doors into balcony entrances creates uninterrupted views out to the surrounding landscape due to the minimalistic frame design.

The abundance of configurations and adaptations available with these sliding doors provides a modern aesthetic to properties. A pocket door is a design that works exceptionally well for balconies. The ability to integrate a pocket door into the installation, allows the sliding doors to be hidden within a pocket in the wall cavity to provide a completely minimalistic design that appears almost frameless when the doors are open.

Pocket doors are not limited to openings that lead to a walk-on balcony. For Juliet Balconies, frameless glass balustrades can be integrated into the minimal windows® sliding doors design. 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. Glass balustrades installed with our minimal sliding doors create beautifully uninterrupted views out into the surrounding landscape.

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

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


Base Details

There are two base track options for the Keller minimal windows® sliding doors:

The Flush Track

This base option boasts an impressive 38mm deep aluminium base frame installed below Finished Floor Level (FFL), with a 12-13mm deep track. This incredibly minimalistic base track provides the sliding doors with a full floor-to-ceiling glass finish offering an almost frameless appearance around the whole frame.

The Freeway Base

A completely flat finish across the base track from inside and out without any dips or regresses within the floor. The resulting glass elevation has approximately 37mm frame visible above finished floor level.


IQ have designed a bespoke base and drainage solution for minimal windows® sliding doors, which is highly suitable for the wet weather environment of the UK.

IQ Glass install a solid Neoprene base block beneath each installation on Keller minimal windows and the triple glazed Keller minimal windows® +4. This unique base detail creates a solid continuous base for the slim aluminium framing to be installed onto and acts as part of the drainage system for these slim framed Keller sliding 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 'runoff groves' to drain the water away. IQ Glass can also integrate our flush threshold drainage channel into the minimal windows® installation for a flush external drainage solution.

Our integrated drainage channel can take up to 120 litres of water per minute for high levels of water egress. To protect the drainage system from becoming clogged with dirt and deposits, a slot drain sits on top of the drainage system. It can be manufactured in a range of colours including champagne, GT Silver, Titanium and Black. The slot drain can be easily removed per meter length for cleaning.


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

Handles, Locking and Ventilation

The Keller minimal windows® sliding doors system has been tested to receive a security rating of WK2/RC2 for high-quality protection against burglars and vandalism. The security testing was carried out at the prestigious Rosenheim Institute in Germany.

There are several locking options for these slim framed sliding doors. A two-point thrust level locking mechanism can be installed into the frame which is only accessible from the inside of the building – which means the locking mechanism is virtually impossible to tamper with. This locking system is excellent for sliding doors that lead out into rear gardens and patio areas that wouldn’t be used as an entrance door to the property.

If external locking is required, IQ Glass can offer an electrical locking system, an external wall mounted key lock or a key lock that is integrated into the frame detail on the sliding doors.

The minimal windows® sliding doors do not come with trickle ventilation options, however, IQ can offer a ventilation option called ‘Slot Aeration’ whereby you can lock the minimal windows® at various open positions, 20/40mm for instance, which allows full ventilation down the full length of the sliding doors.

Insect Screens and Automation

The minimal windows® sliding door system is an incredibly versatile design that has several accessories and automation available if desired.

Insect screens can be integrated into the design of a minimal windows® sliding door system. The screens can be installed on their own 60mm deep track, designed to slide along the track in the same way that the glass doors do. Insect screens are available on all configurations including corner opening and bi-parting doors. These insect screens allow light and ventilation, whilst keeping the inside spaces free of insects and mosquitos.

Automation is available for the minimal windows® sliding doors. IQ Glass would recommend automation if each sliding glass unit weighed over 500kg, any unit lighter than this should be easy to move manually. To see for yourself, why not visit the minimal windows® sliding doors installed at the IQ Glass Showroom in Amersham, Greater London, which are almost at the threshold before automation would be required. Arrange a showroom visit with us to see and slide these doors yourself.

Automated minimal windows® sliding glass doors can be managed through various controls. The automated motors can be operated via a smart home automation system installed on a mobile device or tablet through an App or specialist home automation software. A switch on a wall can be installed to provide a traditional form of control.

ASK US ABOUT OUR Minimal Windows Slim Framed Sliding Glass Doors


Commercial use

sliding doors with glazing bars

Glazing Bar Designs

In order to create a timeless glazing design, it is possible to integrate glazing bars into the glass design within a minimal window. The glazing bars are applied to the surface of the glass unit with a spacer bar included within the gas cavity. This creates a more authentic glazing bar design.

Due to the technical aspects of integrating internal spacer bars, applied glazing bars and ensuring a high level of finish we recommend a maximum glass size of 1300mm wide x 2440mm tall per sliding or fixed pane.

The glazing bars can be applied to the sliding door in whatever design you require and can be powder coated to any request RAL colour reference. In most cases, this will be the same finish as the slim outer frames.

IQ Projects is the specialist commercial division of the IQ Group - www.iqprojectsuk.com


minimal windows Technical Specification Sheet

IQ GLASS DRAFT NBS - minimal windows

minimal windows Premium Brochure


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