A BASEMENT swimming pool and fitness area is being built top down in an £12M house in London's Kensington.
The area measures 24m long by 5m wide, with a depth of 7m.
After the ground level floor slab is cast, equipment for the excavation and reinforced concrete works must be lowered through a confined moulding hole.
'The top shoring frame must then be assembled within the excavation before excavating below this level, ' explains Seamus Gaughan, managing director of contractor M&K Builders.
'The second temporary frame level is then installed at a lower position to provide support to the piled walls. After assembling the hydraulic frames within the excavation we can excavate to swimming pool formation level.' Groundforce Mechplant supplied design and specialist equipment for this complex job. The company's Mega brace modular hydraulic brace was used in 5m sections and this allowed the 24m long frame to be built up within the confined space. Two levels of Mega brace and hydraulic struts were used.
Where there were kinks in the piled walls of the basement, the waling was stepped out to follow the line of the piles.