Ilona Rose House, London

Contract Summary

A 4-level basement and 9 story structure above ground.

Works involved the construction of a waterproof SRC perimeter capping beam to secant piles. Installation of 3 levels of temporary propping (700ton) and bulk excavation to B4 level.

At B4 level the slab was constructed with watertight concrete on pile caps and tied to the perimeter secant piles. Geothermal pipework to all piles and connections to chambers through pilecaps and slab.

Central SRC core 1 and 2 constructed on a large central pile cap and then jumped using Efco formwork from B4 to level 09. Once the core was jumped, the steel stairs were installed and cores were capped. Tower Crane was then relocated to the top of Core 2. The steel frame commenced from the B4 slab with a traditional 300mm SRC slab at B3 tied to perimeter secant piles and SRC encased steel columns. Steel frame continued with steel columns encased with SRC and traditional falsework slabs in place of metal decking from B2 to B1 for management of acoustics for the end user (Warner Brothers Studios)

Temporary Propping could not be removed until the B1 slab was complete, leaving 2 levels of propping to be removed under the new slabs at levels B3 to B2 and B2 to B1. Propping at ground floor removed using tower cranes.

Cavity drain installed to the 4-level basement perimeter secant piles. Concrete on metal decking from ground floor to level 09.

Installation of waterproofed concrete capping beam & underpinning to existing structure. Works included:

• Breaking down concrete guide wall & piles.
• Reduce level dig to formation level for capping beam
• Installation of reinforcement and formwork
• Waterproofed concrete to capping beam
• Two stage underpinning of 19th Century structure

Realtime summary of work scope:

• Construction of reinforced capping beam to secant piles.
• Installation of three levels of temporary propping as bulk excavation progressed to basement 4 level.
• Basement waterproofing installed to a Type B, C - Grade 3 specification to BS 8103:2020.
• Geothermal pipework in the basement slab and pile caps.
• Two large reinforced concrete cores jumped using the Efco formwork system from basement four level to level nine.
• Realtime worked closely with the structural steel contractor to cast in embedment plates for post fixed connections.
• Forming 300mm thick reinforced concrete slabs to basement level 3, 2 and 1.
• Removal of temporary works propping once B3, B2 and B1 slabs were formed.
• Concrete topping to metal decking from ground floor up to level 9 roof.

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