November 5, 2014

6 Examples of Double Height Glass to Narrow London Properties

Written by Rebecca Clayton

a rear view of a double height glass side infill extension in London

Double height extensions are often an extremely cost-effective way to increase internal living spaces in a house dramatically whilst enabling the creation of open living areas.

The two most expensive elements of most builds are the foundations and roof. When creating a double-height extension, you are still paying the same base costs for these expensive yet necessary parts of construction but are spreading it over two floors and doubling the extra space created through the new extension.

4.5m Tall Double Height Glass Doors to London House

When creating any type of extension - especially in tight London properties where side windows are not an option - getting light into a new extension and the further living spaces is an interesting design obstacle.

If a double-height extension is being created you no longer have the option to easily add in roof lights to the design to allow light into the first storey. In these cases, a large rear elevation of glazing is often the best solution, bringing a striking aesthetic to a double-height extension and allowing floor to ceiling walls of light.

double height sliding doors Kingston Road House Extension with 4.5m tall sliding glass doors.

This double height rear extension in West London included a set of 4.5m tall sliding glass doors to the rear. The double height glass doors where created from our slim sliding door system with slight modifications to allow for the extended height. Even with these modifications the oversized glass doors maintained their 21mm vertical sightline and flush, frameless threshold at the base. 

The tall sliding glass doors offer light to the rear kitchen and also allow natural light to penetrate the cosy living area and nook located on the mezzanine balcony and upper ground floor. 

5.7m Tall Double Height Glass Side Return Extension

Narrow London houses are often terraced homes, with multiple stories stacking on top of each other to create a tall narrow property. Historically, terraced homes in city centres included a side return; a disused area of the home to the side of the kitchen. A modern extension type is to fill in this side return of a terraced house and contain it within the living spaces of the house. 

This double height glass extension in Kensington does just that; filling in the side return of the terraced house and containing into the interior of the house. The result is a light and bright living space and kitchen to the central London home. 

a rear view of a double height glass side infill extension in London Gloucester Walk, double height glass side infill extension.

The double height glass extension included a set of 5.7m tall sliding glass doors to the rear. The sliding glass doors were ultra tall, created from our slim sliding glass door system with 20mm vertical sightlines. Even at this height, the sliding glass door was manually operated, allowing the home owners to open the full height of the 5.7m sliding glass door bringing ventilation into the ground and upper ground floor living spaces. 


Double Height Glass Extension with Fixed Glass Above

This is often a solution used as the first option for architects designing a double-height extension. At the base, you can use the door system of your client’s choice (be that sliding or bifolding doors) that give access to the rear garden. Above you can specify fixed glazing.

The most minimal way to achieve this design is to use a slim framed sliding door system to the base (like the minimal windows® system) with frameless structural glass above.

double height rear extension Double Height rear extension on Paultons Street with minimal windows®, structural glazing, solar control coatings and heated glass.

That is what was used on this double-height glass extension in Paultons Square London. At the base, minimal windows® were used in a bi-parting configuration, opening at the centre on the same track. The contractor installed a horizontal steel section to support the door opening and then above was a four-pane structural glass window. A pressing was used to the central joint of the structural glazing to mimic the biparting frame size of the sliding doors below.


Double Height Glass Extension for Two Floors

Sometimes a glass extension will not include a void internally. Instead, the new extension contains two separate floors and the glass façade is spanning over two storeys.

In these cases you can create exactly the same glazing design to the upper and lower sections of the extension, ensuring that the design is cohesive from both the inside and out.

A good example of this is Edis Street which included a double-height rear extension with a living space to the ground floor and a living space above. In order to ensure that the two floors looked like part of the same extension the architect specified minimal windows sliding doors to both storeys in the same sliding configuration.

a double height glass extension with two sets of sliding doors on two floors Edis Street, double height glass extension with two sets of matching sliding doors, one on each floor

On the upper floor, a frameless glass balustrade was used to block off some of the sliding door opening and protect against the level change.

An aluminium pressing was used to cover the floor structure between the two sliding door installs and make the entire elevation look cohesive.

Including frameless glass balustrades into a minimal windows® opening can create a really slimline glass Juliet balcony design that works really well on upper floor spaces.


6m Tall Double Height Glass Doors

A striking finish can be achieved by creating a double elevation of glass from a single door system. Many modern glass doors are pushing the boundaries of what is possible and can be designed to heights reaching 6m tall.

When specifying double-height doors you need to keep in mind the specific performance requirements of your project. 6m tall doors are not recommended for projects that will experience a high wind load, but most London extensions would be suitable for this type of bespoke glazing installation.

6m tall sliding doors on Portland Road 6m tall sliding doors on Portland Road

Portland Road is a good example of a double-height door done well. The sliding glass door was almost 6m tall and was engineered from our minimal windows 4+ sliding system. The aluminium sliding door has been tested to a maximum height of 4.5m however the technical detailing team at IQ were able to make several changes to the system to allow it to be installed at 6m tall on this project.

Thanks to the various adaptations made to the sliders the 6m tall doors were able to be manually operated without the need for a motor.


Double Height Glass Sash Window

For a real wow-factor, you could create an entire double-height elevation of glass to your extension using a vertical sash window. IQ offers a vertical sash window based on the minimal windows® sliding doors, giving you horizontal framing of just 21mm.

A minimal Vertical Sash window at Dormers. A minimal Vertical Sash window at Dormers.

The vertically sliding window can open at the bottom to allow access outside whilst the upper glazing remains in place like a fixed window. The result is an opening at the base of the extension with fixed glass overhead (like the first option) but with very minimal 21mm horizontal sightlines and no need for additional steels.


Double Height Glass Lightwells

For more inspiration for double height glazing, check out our dedicated inspiration article about lightwells. Find out more about creating lightwells with double height elevations of glazing and slim sliding glass doors. The Only Way is Up


What Next?

If you are planning or designing a double-height glass extension and want to incorporate some of the architectural glazing solutions mentioned here, just get in touch with the team at IQ. We have technical advisors on hand to offer you specification advise and offer solutions to achieve the design goals you have.

Visit our contact us page to see all the ways you can get in touch with the team at IQ.