With a railway line on one boundary of an old car park site, existing buildings and a car park on the other side, protected woodland and park to the rear, and a restricted site entrance, the key to Daren Milne’s construction of this five-storey block was good access control and superb sequencing.
A review of the phasing strategy gave him the opportunity to build the basement car park and the four-storey concrete frame in tandem. While the basement, which covered only half the development, was being excavated, he got the frame construction on the other side away, gaining several weeks on the original programme.
He introduced precast concrete columns to reduce the crane hook time requirement. Delivered straight to the development from the factory, they were immediately lifted into position. Because he had the rebar matting for the reinforced floors delivered to the site rolled and preslung, it was ready to lift straight into position, reducing manual handling, storage and waste, and further minimising crane time and the floor construction period. The initiatives took two months out of the programme.
His use of a lightweight permanent shutter system for the internal stairs meant the shuttering could be lifted into position and fixed without mechanical lifting equipment. Not only did the construction of the stairs come off the critical path, but there was also a cost saving.
And his choice of a lightweight steel structure for the top storey reduced the load on the concrete frame below, permitting fewer columns and eliminating downstand beams in the frame. Savings in costs and time flowed from the earlier watertightness of the upper floor, where internal works progressed even as the lower levels were still backpropped and curing.
Having worked on everything in his 34-year career from dog kennels at Gatwick Airport to listed building conversions, from supermarkets to petrol stations, Daren had more than enough in the tank for this challenging development. Indeed, it all went so well that he even pulled off the tricky feat of smoothly co-ordinating materials movements and the coming and going of sales staff and potential customers through the sole site entrance when the development was opened up for sales.