U&M Group

Basement

Wednesday, January 27th, 2010 AT 05:31AM

Cheval Place. London SW7

We were consulted as to the feasibility of constructing a basement beneath an existing car park for the installation of an electric car lift, and subsequently to form the foundations and ground floor of a residential house.

The site was restricted in the extreme, buildings on the boundary on three sides, public carriageway on the boundary to the front, and all at the end of a cul-de-sac mews just off Knightsbridge. There were many logistical issues to consider and these included the temporary support to the adjacent structures and road, the problems with drainage and sewerage connections, the movement of materials on site and disposal of spoil, all on a site of plan area 4.50 x 8.0 metres! The excavation depth was generally 4 metres from ground level, although over 25% of the plan area it was necessary to deepen this excavation to 5.50 metres to accommodate the lift motor and control equipment. (This was eventually converted to living accommodation when the lift was in the raised position!).

The adjoining properties were underpinned to the required formation depth and this had to be carried out in very small sections, carefully supported, as ground generally comprised of loose and unstable hogging and sands. A reinforced concrete beam was also constructed under the adjoining building immediately on the left and right to provide additional support to the existing structures.

1st Floor

Entrance Level

2 Lower Floors

Longitudinale Section

 

Once the site was surrounded by fair faced retaining walls, the bulk excavation was carried out in small sections as the basement slab had to be constructed in sections to provide continuous lateral support. When this exercise was completed, the suspended concrete ground floor deck was cast incorporating all of the upstands for the proposed building over.

We also won the contract in limited competition tender for the construction of this very unique house. The construction was generally traditional masonry with a steel trussed-pitched roof finished with an artificial slate. However, the finishes were far from traditional as the entrance was a combination of glass and stainless steel, the rear of the property was clad in zinc, the staircase and landings were steel and toughened, sand-blasted glass, the walls and floors of the bathroom were clad in Italian marble, as was the decks of the car lift and even the wash hand basin and surround was hand made on site using the same material. Finally, the kitchen units and worktops were clad and made from seamless stainless steel moulded on site.

  
  

This project was extremely unique in both its location, style and design and many different problems were encountered at each stage of the project. These were overcome as our in house designers and the Architect had a very close working and co-operative relationship which produced a truly unique building that has been highly acclaimed for its design and workmanship in many leading Architectural digests both in the UK and abroad.