This glass extension in London was designed as part of a wider renovation to a terraced house, where the brief was to increase usable ground-floor space and strengthen the connection between the home and the garden. IQ Glass designed and installed a glazing package of frameless structural glass walls, a structural glass roof and an ultra-slim bifold door, using minimal glass-to-glass junctions to keep the extension visually light. Solar control glazing was specified throughout so the new open-plan living space could achieve high daylight levels without compromising comfort.
Products Used
Project Partners
DIZarchitects
Location
London, UK
Glass extension in London on a constrained terraced plot
The design challenge for this glass extension in London was to create a highly glazed rear addition on a tight terraced plot while preserving as much of the existing garden arrangement as possible. DIZarchitects responded by extending outward into the patio area while maintaining the established flowerbeds, using glazing as the primary architectural solution rather than treating it as infill within a heavier built form. Frameless structural glazing was specified to maximise transparency at the perimeter, while the structural glass roof had to deliver top light across the depth of the new room. The result is a rear extension that feels more open and visually connected to the outside without relying on bulky framing or conventional solid returns.
Frameless structural glazing to the side returns
The side elevations of the extension use frameless structural glass to solve the challenge of bringing light into a narrow rear addition without visually closing down the space. These vertical glazed elements are silicone-jointed to the structural glass roof above, creating direct glass-to-glass connections with no visible finishing details at the key junctions. This approach reduces the visual weight of the side boundaries and allows the extension to read as a cleaner glass volume, while still delivering the thermal performance required of a modern glazed envelope.
Structural glass roof and bifold facade alignment
A second challenge was to combine top light, full garden access and a controlled rear elevation within one coordinated composition. The structural glass roof was split into three panes, with slim steel supports introduced between the panes as the structural solution to the larger spans. Those supports were aligned with the bifold leaves below so the roof and door composition read as one symmetrical facade rather than as separate glazing elements. At ground level, the five-pane ultra-slim bifold door opens the rear elevation to the patio with a flush threshold detail, allowing the glass extension in London to move from enclosed room to open garden edge when required.
Performance considerations
This glass extension in London had to balance a minimal appearance with the thermal and environmental control expected of a modern living space. The frameless structural glazing uses a thermally broken fixing system so the side walls can remain visually light without sacrificing insulation. Solar control coatings were applied throughout to limit solar gain and reduce the risk of overheating beneath the highly glazed roof and rear elevation. At the main opening, the flush-threshold bifold detail supports a cleaner transition to the patio while maintaining the practical requirements of a daily-use family space.
South Hill Park shows how a glass extension in London can unlock daylight, garden access and usable floor area on a constrained terraced plot without relying on visually heavy construction. This approach is particularly well suited to urban rear extensions where architects and specifiers need frameless structural glazing, roof glazing and large opening elements to work together as one coherent architectural glazing package. To discuss a comparable glass extension in London or another structural glazing scheme, contact IQ Glass with your drawings and project requirements.
