Cannon Green Staircase

Cannon Green’s RC cast in situ polished concrete staircase is an Ocubis project in conjunction with John Robertson Architects (JRA), Civic Engineers and Six Smith Build. Lazenby built and installed the 21m long, 7m high and 7.5m wide (at the top) inverted amphitheater cast in situ Pewter concrete staircase. This staircase was designed by JRA and structurally engineered by Civic Engineers, incorporating BIM modelling due of the intricacies of the reinforcement design. This self-supporting staircase is tied into the structure with a steel stringer to convert the loads and moments down through the steel columns.

Lazenby installed traditional formwork to create the stepped soffit that leads up to the inverted amphitheatre steps. Lazenby then installed a false work system (from Ischebeck Titan/Inform UK) enabling the formworkers to create the radius former inverted amphitheatre undercarriage that is visible from the restaurant (Drake & Morgan). The reinforcement was then added to the soffit and steps; the carpenters then added formers and attached nearly 700 DDA studs to the formwork prior to the casting of concrete.

Lazenby’s integral-coloured Pewter polished concrete was batched on site into a C32/40 concrete supplied by London Concrete. The project used approx. 24 cubic meters of concrete and 6 tonnes of steel reinforcement. Ground floor to the top landing and seating area is just over 4m high, 21m long and 7.5m wide with 24 shallow risers and 3 functional landings. The first 3m wide step widens to a 7.5m inverted amphitheatre style landing featuring single and double height steps.

Lazenby’s 8 master craftsmen were onsite for the duration of this 12-week project. Lazenby won the Cannon Green project based on the ability to deliver unrivalled experience for projects of this scale and magnitude. Engineering from Civic Engineers, design by JRA and experience and know-how from Lazenby’s master craftsmen created a steel and concrete masterpiece of exacting standards.