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Gianni Botsford reveals ‘invisible’ canalside extension

Gianni Botsford Architects has completed a glazed extension to a townhouse on the Regent’s Canal in North London

Designed to be invisible from the adjacent canal the 8.3m² addition contains a small library and a study.

Built on a concrete base, the extension, which is constructed from unframed glazing, is sunken so that the seats are at floor level.

Structural description by TALL Engineers

‘The glazed extension was created from four large double glazed units, one for each of the three walls and another for the roof, the largest being 2.7m by just over 2.3m in size and weighing 375kg. The outer pane is 12mm toughened glass, while the inner is laminated with an ionoplast interlayer (Sentryglas plus) from two 6mm heat strengthened sheets. All glass is specified with a low iron content to ensure maximum clarity.

‘The glass roof is supported directly off the glass walls and secured with a white coloured structural silicone, white spacer bars and white painted strips inside the double glazed units at junctions to provide a uniform appearance.

‘Where the glazing abuts the original building the glass is held between two angles chased into the brickwork to ensure they are concealed behind the wall finishes.’


Project Data

Budget £65,000
Total area 8.3m²
Client Private
Architect Gianni Botsford Architects
Structural engineer TALL Engineers
Services engineer Pearce and Associates
Contractor Verona Construction
Landscape architect Todd Longstaffe-Gowan
Lighting Modular, Davide Groppi
Glazing specialist Cantifix
Corian installer Midas Solid Surface

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