Thames Water: Twyman House

The proposal is to construct three new predominately residential blocks on the site and refurbish an existing building.

  • Project Cost £25 million
  • Architect Chassay and Last Architects
  • Images Fluid / Chassay and Last Architects

The three largest blocks are joined to form an L-shaped building bounding the Southern and Eastern edges of the site. The building steps up from 4 storeys in the South West corner of the site to 8 storeys in the South East corner, and then back down to 7 storeys in the North East corner. A fourth smaller 3 storey block is detached and will be a refurbishment of an existing property extending through to Bonny Street in the North West corner of the site. It is not proposed to include a basement so all the blocks will be built off a new lower ground floor slab which sits below Camden Road.

The site is crossed by a combined sewer running parallel to the canal path and the River Fleet Tunnel cuts the corner of the site. As a result, it was necessary to agree the foundation design with TWUL and also to incorporate a method of accessing the sewer from the courtyard of the proposed building.

Thames Water Sewer


  • Possibility of rupturing major sewer.
  • Possibility of sewer damage and collapse causing road collapse.

Design Procedures

  • We contacted TWUL at an early stage in the project before any design work had commenced and agreed methods of construction that would be acceptable close to the sewer.
  • We carried out a detailed site investigation and TWUL carried out a condition survey prior to any work starting.
  • Based on our drawings, meetings, TWUL meeting and drawings the feasibility of the proposed works was established and agreed with TWUL.