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Netherford Road uses steel framed glazing for a London rear extension designed by Sinclair Studios to increase the usable ground-floor space while retaining the character of the original property.

IQ Glass supplied a coordinated package of thermally broken steel framed doors, fixed and opening steel windows and a Mondrian® glass extension. The glazing extends across the rear and side of the house, with a structural glass roof bringing daylight into the side infill.

A muted RAL 7009 green finish was specified across the steel framing, creating a consistent relationship with the planting and green interior accents while contrasting with the traditional brickwork.

Products Used

Featured In

Grand Designs Magazine, Livingetc

Project Partners

Architects: Sinclair Studios

Photographer: Luke Weller

Location

London

kitchen extension with earth-toned interior and green framed glass patio doors

up and over glazing with slim, green steel frames for a biophilic design

Steel framed glazing within a traditional London rear extension

The design brief required additional kitchen and living space without removing the architectural character of the existing London house. The extension therefore combines contemporary glass construction with steel framing whose proportions, glazing bars and colour give the new elevation a more traditional character.

The ground floor was extended towards the garden and into the side return. Large glazed openings provide direct views and access to the garden, while overhead glazing addresses the deeper part of the plan where daylight from the rear elevation alone would be limited.

Steel was used consistently across doors, windows and the glazed extension. This allowed the different opening and fixed elements to share the same narrow framing language rather than reading as separate systems.

Thermally broken steel doors with bespoke glazing bars

The principal garden opening uses thermally broken steel framed doors configured as a pair of casement doors with fixed sidelights.

Bespoke glazing bars divide the glass into smaller proportions, while solid steel panels at the base of the doors reinforce the traditional appearance. Even the hinges were powder coated to match the RAL 7009 frames, maintaining the same finish across the complete door assembly.

A flush threshold creates a level transition between the new kitchen and garden patio. The thermally broken steel profiles allow the traditional steel aesthetic to be used externally while providing the thermal separation required for a year-round living space.

Structural glass roof and steel-framed side infill

The side return uses a combination of fixed and opening steel framed windows beneath a structural glass roof.

An outward-opening window provides additional ventilation, with a triangular fixed pane above connecting visually into the roof glazing. Structural glass panes and slim steel support sections then continue overhead, bringing daylight down through the side infill and into the enlarged kitchen.

This up-and-over glazing strategy makes use of both the vertical wall and roof plane rather than concentrating all of the glass on the rear elevation. The result is a more evenly lit interior and a stronger relationship between the extension and garden.

bespoke slim framed window with green steel window frames

unique home extension with a biophilic design inspired by the botanical gardens. Slim steel-framed glazing was used with unique green frames

Performance considerations

The performance strategy for the steel framed glazing for a London rear extension centred on thermal separation, daylight, ventilation and the coordination of several different glazed elements.

The external doors and windows use fully thermally broken steel framing, reducing heat transfer through the metal profiles while retaining the narrow dimensions associated with traditional steel glazing.

Natural ventilation is provided through both the double doors and the opening steel window within the side infill. The structural roof glazing introduces daylight from above, helping illuminate the deeper parts of the extended ground floor.

The consistent RAL 7009 finish also allows the doors, windows, roof supports and bespoke junctions to operate as a single architectural composition despite their different functions.

Technical details

Thermally broken steel framed doors: double casement configuration with fixed sidelights
Door detailing: bespoke glazing bar layout with solid steel panels at the base of the doors
Threshold: flush transition between the kitchen extension and garden patio
Steel windows: fixed and outward-opening elements incorporated into the side infill
Upper glazing: triangular fixed steel-framed pane connecting the vertical glazing with the roof
Structural glass roof: structural glass panes supported by slim steel sections above the side extension
Finish: muted green RAL 7009, with hinges powder coated to coordinate with the steel framing
Glazing strategy: rear garden doors, sidelights, side-infill windows and overhead structural glazing coordinated as one package

Netherford Road demonstrates how steel framed glazing for a London rear extension can provide contemporary levels of daylight, garden access and thermal performance while retaining a visual relationship with traditional architecture.

The green steel framing, bespoke glazing bars and structural roof glazing give the extension its own architectural identity, while the combination of fixed, opening and overhead glass responds directly to daylight, ventilation and circulation requirements.

Architects and homeowners developing comparable side return extensions or period-property renovations can contact IQ Glass to discuss thermally broken steel doors, Mondrian® glazing, structural glass roofs and bespoke junction detailing.