Client:The Standard Hotel
Structural Engineer:Heyne Tillett Steel
Concrete Contractor:Restore London
The concrete structure, originally built in the mid-70s as an annexe to Camden Town Hall, was repurposed, adapted and the exterior cleaned to now house an upmarket 266-room hotel.
The original structural façade comprised glazed precast concrete panels that were in good condition, with just a few mastic joints to reinstate and a few small cracks which were easily repaired. The concrete had a large whitish aggregate in it, and with the dirt removed the true colour can again be appreciated.
The original stair core and roof-level plant room that ran up the right-hand side of the building and connected it, via a covered walkway, to the neo-classical town hall next door, was removed as part of the renovation. With this core removed, the building is now a standalone structure. Its removal did have consequences, however, as it was a key contributor to lateral stability. Without it the building would sway from side to side. The solution was to introduce two new concrete stability cores.
One of these new stability cores is a new lift shaft, constructed from in-situ concrete, which has been stitched into the original reinforced concrete structure and runs from basement to roof. The second is a C-shaped core, also in in-situ concrete, that rises from the basement to the fifth floor. This encloses a shaft for dumb waiters at basement level, but on the upper floors is simply a C-shaped shear wall enclosing bedrooms.
The construction of both new cores was sequenced early in the programme to stabilise the building prior to the removal of the old stair core. The floors are made from waffle slabs which were just 106mm thick, but with 300mm downstands. The 406mm total allowed long spans to be achieved with relatively little concrete.
As well as boasting admirably reconfigurable floorplates, the existing concrete frame also proved robust enough to take three further storeys. This added 1,914m2 to the building’s existing 15,360m2 and was vital for the commercial viability of the scheme. To save weight, the rooftop extension was constructed largely from steel, with composite metal deck slabs with a 175mm depth of concrete.
The 10th floor, featuring a restaurant and entertainment area, is acoustically separated from bedroom accommodation below by an extra 150mm slab above a 100mm air gap. This is supported above the 175mm ceiling slab by sprung jacks to absorb noise and vibration.
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