Frameless Structural Glass and Glazing Frameless Sliding Glass Doors & Windows Rooflights and Roof Glazing systems Invisio® Structural Glazing System Technical Glass Solutions Timber Windows and Doors Glass Doors Window Systems Steel Windows and Doors Steel Look Windows and Doors Fire Rated Glass Systems Internal Glazing Architectural Accessories Aluminium Windows and Doors for Architectural Glazing Automated Glazing Mondrian Windows and Doors Triple Glazing Internal Steel Doors

Glazing Applications FAQ Technical Advice CPD

About Us Careers Why IQ International Customer Satisfaction Glass Repair

News Awards Media Our YouTube Newsletter

Glendale Mews is a rear extension with large sliding glass doors and a glass box window in Bromley, transforming the dark and divided ground floor of a 1960s semi-detached house. Type Studio reconfigured the existing layout and replaced a poorly built extension with a brighter kitchen and living space connected directly to the garden.

IQ Glass supplied slim framed sliding glass doors, a structural glass corner, a frameless oriel window and an Invisio strip rooflight. Photography is by Lorenzo Zandri.

Products Used

Project Partners

Photography: Lorenzo Zandri

Location

Bromley, London

a frameless corner window set below a timber batten ceiling

a pair of slim glass doors to a rear extension in London shown partially open

Reconfiguring a 1960s semi with large garden-facing glazing

The existing ground floor lacked daylight and had a weak relationship with the rear garden. The replacement extension therefore needed to improve the thermal envelope while creating a more open layout and drawing natural light into the original house.

Large glazed openings were positioned around the new living spaces rather than concentrated on a single elevation. The sliding doors provide the primary garden access, while the frameless corner increases views in more than one direction and makes the extension feel wider.

A projecting glass box window creates an additional seating area at the side of the extension. The strip rooflight then addresses the deeper part of the plan, defining the junction between old and new and bringing daylight towards the centre of the original house.

21mm sliding doors with a frameless corner connection

The garden elevation uses slim sliding glass doors with 21mm vertical sightlines and flush threshold detailing. The minimal framing maximises the glazed area while providing direct access between the new living space and garden.

At the return, a frameless structural glass corner extends the view around the extension. Removing a visually heavy corner profile allows daylight to enter from multiple directions and creates the wrap-around effect intended by the architect. IQ Glass's guide to glass-to-glass corner windows explains how concealed structural glazing can be used to resolve these junctions.

Oak parquet flooring and exposed timber roof beams soften the highly glazed architecture and establish a consistent material relationship between the extension and interior.

Frameless glass box window and strip rooflight

A large oriel window projects from the side of the extension to create a dedicated window seat overlooking the garden. Structural glass panels meet with silicone-bonded glass-to-glass joints, allowing the window box to remain visually frameless while extending the usable internal space.

The strip rooflight runs along the junction between the existing house and new extension. Its position brings overhead daylight into the deepest part of the plan, where the original building would otherwise restrict natural light.

Together, the oriel window and rooflight supplement the large sliding elevation, ensuring that daylight enters from the side, rear and above rather than relying on the garden doors alone.

Performance considerations

Performance for this rear extension with large sliding glass doors and glass box window in Bromley centred on daylight, thermal comfort, weather performance and the relationship between the new glazing and existing house.

The thermally broken sliding system allows large areas of glass to be used while maintaining year-round performance. Flush threshold detailing incorporates drainage below the finished floor level, combining a minimal transition with the water management required at an external opening.

The structural glass window uses the thermally broken Invisio fixing system, with the perimeter framework concealed within the surrounding construction. The strip rooflight uses silicone-jointed structural glass to bring daylight towards the original building without requiring visible intermediate framing.

This coordinated approach allows the sliding doors, structural glazing and rooflight to perform different architectural functions while reading as one glazing package.

Technical details

Slim framed sliding glass doors: 21mm vertical sightline; max tested sliding pane 8.5m², up to 4m high and 500kg; typical Uw greater than 1.1 W/m²K; Air Class 4 / Driving rain Class 7A / Wind Class C4/B5; PAS 24 security
Threshold detailing: flush threshold between the internal floor and garden, with drainage integrated within the base construction
Oriel window: frameless structural glass box using concealed thermally broken Invisio fixings; 63mm fixing profile depth; typical Ug 1.0 W/m²K; glass specification calculated to project requirements
Strip rooflight: silicone-jointed structural glass positioned between the original house and extension; unsupported strip rooflights can span up to 1.3m wide, with individual glass units up to 6m long depending on specification and installation access
Project glazing strategy: large rear sliding elevation, frameless structural glass corner, projecting glass box window and strip rooflight coordinated to introduce daylight from several directions

Glendale Mews demonstrates how a rear extension with large sliding glass doors and a glass box window in Bromley can transform a dark 1960s semi-detached house without relying on glazing at the rear elevation alone. The sliding doors create garden access, the structural corner expands the outlook, the oriel window adds usable space and the strip rooflight brings daylight back into the original plan.

The project is particularly relevant to architects developing contemporary rear extensions where daylight, garden connection and minimal structural detailing need to be considered together.

Architects and specifiers can contact IQ Glass for technical advice on large sliding glass doors, oriel windows, structural glass corners and strip rooflights.