Prince Albert Road

Glass walkway to subterranean side extension of prestigious listed London property

Prince Albert Road is a Grade II listed property overlooking Regent’s Park, where IQ Glass delivered a glazing package for a 200 sq m semi-subterranean side extension by Alan Higgs Architects. The project uses a structural glass walkway in London to link three new living spaces, including a garden room, dance studio and television room, while keeping the extension visually discreet within the existing garden setting.

The glazing package included a frameless glass link, a continuous strip rooflight, slim sliding glass doors, roof glazing and replacement glazing to the main house. The design was shortlisted for the 2017 RIBA Awards and demonstrates how architectural glazing can bring daylight into below-ground extensions without compromising the setting of a listed London property.

Products Used

Featured In

Shortlisted for the 2017 RIBA Awards

Project Partners

Architect: Alan Higgs Architects

Location

Regents Park, London
Glass walkways lights up subterranean modern extension to luxury home on Prince Albert Road
Oversized full height glazing to the rear garden room of London property extension
Glass walkway to luxury London home overlooking Regents Park
Substantial glazed extension to London home

Structural glass walkway in London for a Grade II listed garden extension

The design challenge was to increase the living space of a prestigious listed home without allowing the new extension to dominate the original building or garden. The site constraints became central to the architectural response. The new rooms are semi-subterranean, invisible from the street and arranged around a mature lime tree, allowing the garden character to remain intact while adding a substantial new floor area.

The extension also needed to maintain the practical use of the site, including car parking above the new structure. This meant that daylight could not be treated as a simple rear elevation problem. Natural light had to be drawn down into the new rooms from above and along the circulation route, using a glass walkway and roof glazing rather than relying only on standard vertical windows.

Iroko cladding was used to soften the garden-facing enclosure, while the glazing created the required contrast between the listed house and the new intervention. The result is a contemporary extension that supports modern living while remaining visually secondary to the historic fabric and Regent’s Park setting.

Strip rooflight over the semi-subterranean walkway

A bespoke structural glass walkway was created using a slim frameless strip rooflight running along the length of the extension. This roof glazing brings daylight into the semi-subterranean plan and helps distribute light evenly between the new living spaces.

The strip rooflight acts as more than an overhead window. It defines the route through the extension and prevents the lower-level rooms from feeling disconnected from the garden above. Its frameless, silicone-bonded detailing keeps the roof glazing visually light, supporting the architectural requirement for a discreet intervention within the grounds of a listed property.

Garden room glazing and slim sliding doors

The extension moves from a high, glazed garden room, described by the architect as a contemporary orangery, through the internal dance studio and towards a television room with a glass corner leading to a terrace with canal frontage. This sequence required different glazing elements to work together across the new plan.

Oversized glazing to the garden room increases the sense of height and openness within the semi-subterranean extension. Slim sliding glass doors provide direct access to the garden, while maintaining a minimal frame appearance when closed. The glass corner at the television room opens the view towards the terrace and canal, reinforcing the relationship between the new living spaces and the surrounding landscape.

Strip rooflight to contemporary extension of luxury London home
Contemporary glazed and timber extension to listed London property

Performance considerations

The performance strategy for this structural glass walkway in London was driven by daylight, thermal control, weathering and heritage sensitivity. The semi-subterranean layout required roof glazing to bring natural light into the centre of the plan, while the frameless glass link needed to remain visually restrained against the Grade II listed house.

The strip rooflight and structural glass elements were detailed to provide a minimal appearance while retaining the thermal performance required for an inhabited extension. Overhead glazing requires laminated inner panes for safety, while thermally broken structural glazing helps reduce cold bridging at the glass interfaces.

The slim sliding doors provide wider garden access and additional daylight, while allowing the garden room to open directly to the landscape. The use of iroko cladding, concealed framing and carefully resolved junctions helped the extension sit within the garden without competing with the listed property, the mature lime tree or the wider Regent’s Park context.

Technical details

  • Structural glass walkway and strip rooflight: continuous frameless roof glazing used along the length of the 200 sq m semi-subterranean extension; structural glass roof systems can accommodate glass thickness up to 37.5mm DGU, typical Ug 1.1 W/m²K and example Uw 1.2 W/m²K; laminated inner pane required for overhead glazing
  • Frameless structural glazing: thermally broken fixing profile depth 63mm; max glass thickness 41.5mm; expected Uw 1.1 W/m²K; minimum fixing setback 55mm; structure deflection allowance 5mm
  • Slim framed sliding doors: 21mm sightline; glass thickness 26mm to 32mm; 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
  • Project layout: 200 sq m semi-subterranean extension containing a garden room, dance studio and television room; new living spaces arranged around a mature lime tree, with car parking maintained above the new structure
  • Heritage and landscape interface: Grade II listed setting overlooking Regent’s Park; iroko cladding used to form a garden enclosure and soften the extension within the existing landscape

Prince Albert Road shows how a structural glass walkway in London can be used to bring daylight into a semi-subterranean extension while preserving the character of a listed property and its garden setting. This approach is well suited to architects and specifiers working on heritage homes where new living spaces must be discreet, light-filled and carefully coordinated with existing landscape constraints.

To discuss a comparable listed building extension, contact IQ Glass for technical advice on structural glass walkways, strip rooflights, frameless glass links and slim sliding door systems.

Associated Products

Roof Glazing

Rooflights and roof glazing can be built with or without a frame, based on the project's design specifications.

luxury new build home with minimal glass facade

Slim Framed Sliding Glass Doors

Sliding doors with ultra-slim sightlines, offering only the highest levels of performance and durability.
Strip Rooflights

Strip Rooflight

Using structural glass to create long runs of glass, connected together with silicone joints.

Aluminium Casement Doors

Aluminium casement doors are sturdy and low-maintenance, offering excellent energy efficiency and security. They come in a variety of designs and colors, and can enhance the appearance and value of any home or building.
Strip Rooflights

Strip Rooflight

Using structural glass to create long runs of glass, connected together with silicone joints.

glass link between buildings

Frameless Glass Links

Frameless glass links create a clear glass link between different buildings or structures using structural glazing.

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