From the team behind Hampstead Renovations · Est. 2009 · Learn more
Case StudySt John's Wood, NW8April 2025

Side-Return Extension, St John's Wood

A premium side-return extension to a Victorian terraced house in St John's Wood, infilling the side passage to create a significantly enlarged kitchen and dining room with a full-length Crittall glazed roof. Westminster City Council planning was obtained and the project was delivered in 14 weeks.

Project Type

Side-Return Extension

Duration

14 weeks

Project Value

£95,000

The Challenge

Westminster's conservation area requirements for St John's Wood meant that the glazed roof had to be carefully designed to avoid any visible mass when viewed from the street. The clients wanted a Crittall steel glazed roof — which is heavier than aluminium systems — requiring a more substantial structural solution. The side-return boundary also had a mature ivy-covered wall subject to the conservation area's character provisions.

Our Solution

Our architect designed a Crittall W20 steel glazed roof that was set below the parapet level of the existing house, making it invisible from the street. Westminster's conservation officer approved the design in 9 weeks. The structural solution used two concrete padstone piers at the boundary to carry the heavier Crittall system. The ivy-covered wall was carefully maintained, with selective cutting back under guidance from Camden's tree officer.

Results

  • Westminster planning approval in 9 weeks
  • Crittall W20 steel glazed roof — set below parapet, invisible from street
  • 16m² added to kitchen footprint
  • New open-plan kitchen and dining space of 38m²
  • Crittall-effect bi-fold doors to garden from new space
  • Bespoke kitchen with Miele appliances and Carrara marble
  • Estimated property value uplift: £165,000

Key Features

  • Westminster conservation area planning consent
  • Crittall W20 steel glazed roof — conservation officer approved
  • Concrete padstone piers carrying Crittall structure
  • Bi-fold doors — matching Crittall profile to garden
  • Bespoke in-frame kitchen with Carrara marble and Miele appliances
  • Wet underfloor heating throughout extended footprint

Specification

ItemSpecification
Glazed roofCrittall W20 thermally broken steel, self-cleaning double-glazed units, RAL 9005
Bi-fold doorsCrittall-profile Kloeber Folding Sider, matching glazed roof sightlines, anthracite
Structural piersReinforced concrete padstone piers, 400×400mm, carrying Crittall base channel
KitchenIn-frame painted kitchen, Carrara marble worktops, Miele Generation 7000 appliances
FlooringLapicida Calacatta Gold marble, 900×600mm, heated throughout extension
UFHHeatmiser Neo-UH6 wet system, manifold under island, individual zones

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