One Angel Court, London
The £125m redesign of the seventies landmark office tower in the City of London is currently undergoing a complete overhaul of its 25-storeys that will see the Grade A office space increase from 18,000 to 28,000m².
It is currently being twin tracked as one of the first BREEAM 2014 commercial office developments in London. The scheme, designed by Fletcher Priest Architects, will also include significantly improved public space for retail shops, restaurants and roof terraces for tenants.
The redesign involves the stripping back of the octagonal tower to its core and installing newly constructed floor plates to increase the tower diameter by over 3m. The building will be fully re-clad with floor to ceiling glazing to offer an uninterrupted 360 degree view across London. The substantial windows of the ‘sky floors’ will feature distinctive fritted glazing and high performance glass to provide a sun shield whilst optimising daylight penetration into the office space to reduce electric lighting requirements.
A significant aspect of the redevelopment is the retention and modification of its existing core as well as the re-use of approximately 60% of the existing foundations. These will reduce the overall construction cost and programme delivery as well as adding to the sustainability credentials.
Sustainability is a key priority for the project, both in terms of meeting the planning targets imposed by the City of London and as a high quality sustainable building by Mitsui Fudosan and Stanhope.
Mitsui Fudosan’s and Stanhope’s commitment to reducing energy and water consumption across their entire office portfolios has supported key sustainability initiatives for the project, including: the stakeholder engagement process; exemplary energy performance; greywater and rainwater harvesting (to reduce water consumption by 50%); inclusion of comprehensive cycle facilities and biodiversity enhancements.
The redevelopment has involved detailed analysis of the existing core and the provision of a temporary stability system for the core tower utilising a new concrete jacket between basement and ground. The existing floors will be replaced with compositely designed steelwork to allow a 3m extra tower diameter whilst the existing concrete floors will be replaced with lightweight floors to allow higher ceilings.
The area of the sub-basement will be increased by approximately a third to accommodate several large plant rooms for housing the building’s newly installed generators, boilers, CHP units, chillers, buffer vessels and sprinkler tanks.
The larger floor plates to the lower levels of the building deliver generous 2.9m floor-to-ceiling heights enhancing daylight penetration. The upper levels have floor plates in excess of 9m depth and 2.7m floor-to-ceiling heights offering a spectacular 360-degree view.
The podium façade has been carefully analysed by our thermal modelling specialists to establish the brise soleil requirements and to assist in informing Fletcher Priest’s façade concepts.
Low carbon initiatives include an on-site combined heat and power unit as a primary heat source supplemented with low NOx, high efficiency condensing boilers. This represents a 29% improvement over the carbon emission requirements of the Building Regulations. Energy efficient LED lighting will also be used extensively across the project with both presence detection and daylight control technology.
The tower will be served by six Mitsubishi lifts which operate at 4m/s, with regenerative lift drives to reduce the power consumption.
Our structural and building services teams have produced integrated 3D models of the structures and MEP services for incorporation in the BIM process which has given a valuable head start to the trade contractors and construction manager Mace.
The scheme is expected to be completed in 2016.