Sunken Extension

Konishi Gaffney Architects, Edinburgh, 2014


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  • Extension    
  • Dining area    
  • Covered exterior    
  • View to house    
  • Kitchen    
  • Plans    
  • Section and Elevation    
  • Axonometric    
  • Construction    
  • Wall Detail 1:10    

Residential house extension inspired by the Walter Segal’s timber frame construction method.

Restricted by planning regulations this extension had to be sunken into the ground to “limit its visual impact”. A sunken design would make construction more expensive which drove the need to find a simple and affordable way to build. As long admirers of the Japan inspired Walter Segal construction method we proposed this system.

A 600mm deep concrete base was sunken into the ground and tanked to ground level. The timber frame was carefully set out at 600 centres and expressed internally at the windows and below the flat roofed ceiling.

Fixed windows with a trickle vent into the cladding cavity were affordable and the cladding in plywood was set out at the same centres and detailed in the Segal way with cover strips to protect the joints. All the timber was then painted externally.

The resultant pattern of the expressed structure is accentuated by extended eaves and the low slung proportions.


  • Begun: Aug 2014
  • Completed: Dec 2014
  • Floor area: 45m2
  • Sector: House
  • Total cost: £52,265
  • Funding: Private
  • Tender date: Mar 2014
  • Procurement: SBCC Minor Works
  • Address: 22 Bonnington Grove, Edinburgh, EH6 6RP, United Kingdom

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