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Barclays Bank Headquarters, London - Green roof Visit the Photo Gallery

Case Study - 1 Churchill Place, London. Barclays HQ

Client

Barclays Bank plc

Architect

HOK [not involved in roof design]

Roofing Contractor

TCL GRANBY and COVERITE

Type of Development

Commercial tower

Reason for Green Roof

“Barclays takes it environmental responsibilities very seriously and this was an ideal opportunity to do something different and innovate.  One Churchill Place was built on reclaimed land, ensuring no loss of Greenfield space in the area. Adding the living roof provides one of our most endangered neighbours with additional habitat and contributes positively to biodiversity and the local community. The reaction of our staff to the new addition has been amazing” (Nita Patel, Barclays Environmental Manager)

Type of Roof

Retro fitted onto paving - biodiverse system

Size of Green Roof

160 meters above ground level, 400m2

Build up of Roof

As this is an extensive roof, it has been constructed of light substrates and planted with drought and wind tolerant plants. In the UK they tend to be sedum mats. These are pre-grown mats, which are rolled out on to the roof. They are light but tend to be a bit of monoculture.

It has been constructed of locally sourced recycled crushed brick and concrete [from Charlton]. This substrate has had a small amount of soil added to it and has been seeded with a wildflower mix. Amidst the crushed brick and concrete are circles of large pebbles. These provide bare areas for rare insects that like dry exposed. Such insects are becoming very rare in the UK.

Build up
Crushed/brick concrete substrate with pine bark, shingle and small area of sedum mat.

Other
Use of calcareous and special conrflower seed mix.
Erosion mat required to prevent wind erosion as vegetation establishes.

Comments

Barclays’ roof is the only true example of a green roof designed for biodiversity in the Isle of Dogs. This green roof has been designed along Swiss principles. There are three mosaic habitats – sedum mat to give instant green cover which will eventually turn to grassland, shingle areas to provide bare areas for xeric invertebrates and calcareous grassland mix to provide structured vegetation for invertebrates.

The roof is the highest in the UK and Europe and most probably the highest in the world designed specifically for biodiversity. Some insects will have arrived in the sedum mat. It is also close to a known black redstart nesting habitat and it is hoped that the species will use the roof to nest and potentially breed.

The roof has not been designed for visual effect and will not be accessible to staff.  However, progress of the Barclays Living Roof will be closely monitored by the University College London as a biological research project to help inform how future green roofs with a focus on biodiversity should be designed. The roof is already the new home for ladybirds and a colony of grasshoppers.

Bernie McGinty (Head of Engineering at Barclays) – “Building a roof designed for biodiversity so high hadn’t been done before. We didn’t know whether the soil would simply blow away, or if a truly bio-diverse culture could spring up so high above ground. In the end we needn’t have worried and I’m delighted with the end result”.

Completion Date

June 2005