7-11 Cavendish Place

Site enabling & top-down demolition of a seven-storey building with basement on a confined office block in Cavendish Place, London to make way for a contemporary mixed-use that is more in keeping with the prime West End location.

O’Keefe’s work for client ACAI, comprised of the soft strip of all floors, asbestos removal, liaison with Westminster City Council for pre-approval licenses, and full stakeholder engagement prior to and during the 28-week contract. A UK Power Networks sub-station with direct access at street level also had to be provided.

Following the strip-out works, 80 props were installed for each pair of floors below the working floor, as construction of the existing building required additional support in the form of temporary propping for the demolition.

The top-down demolition required a full protection scaffold that was erected on the front and rear elevations prior to a planned road closure to enable O’Keefe’s demolition plant to be lifted onto the roof of the building. As the demolition progressed down, adjoining properties, including a listed building at 3 Cavendish Place, were weather proofed and specifically designed temporary flying shores were installed across the site for additional stability.

In addition, a fire escape through the site, for the University of Westminster, had to be maintained throughout which required strict dust suppression measures to avoid setting off the fire alarm. The temporary steel walkway for this had to be designed to not only comply with Building Regulations, but also to not restrict the construction of the new building. This required liaison between O’Keefe and the client’s design team, Campbell Architects, to produce a design that was comprehensive enough to handover to the follow-on main contractor.

Once a section of the ground floor was removed, the steel walkway for the University of Westminster was constructed
and looped into their fire system.

• Contract: 7-11 Cavendish Place
• Client: ACAI Group
• Location: Westminster, W1G 0QB
• Value: £1m
• Duration: 20 weeks
• BREEAM RATING: Excellent
• Scope: Hand & Top Down Demolition, Façade Retention, 7m Underpinning, 3 Party Walls, 2F Basement Formation