The core structural steelwork for Bombardier Aviation’s new 250,000 sq. ft hangar at London Biggin Hill Airport is complete, with construction of the cantilever roof beginning in earnest.

Dorset-based structural steel firm John Reid &Sons Ltd (REIDsteel) and design and build specialist Civils Contracting Ltd (Civils) are building the Bombardier service centre together, with products sourced from British Steel.

On completion, it will be the largest cantilever roofed hangar to be built in the UK for more than 50 years.

The complex cantilever design allows the roofs to safely span the hangar without support from any internal columns, creating a vast floor space capable of housing up to 14 Global 7500s jets at any one time.

John Harrison, senior technical manager at REIDsteel, said: “REIDsteel has strong history at London Biggin Hill, with more than half of the hangars currently standing built by the company.

“This is the most technically challenging yet. With a 165m long central core supporting two 45m cantilever roofs, it is the UK’s second largest after a 46.5m cantilever hangar built at RAF Brize Norton in 1967.

“The Bombardier building is designed to be incredibly robust against unforeseen events.

“Wind loads were checked with codes of practise, against our own full-scale testing and computational fluid dynamics to ensure that even with the doors fully open the hangar will remain within tight deflection tolerances.

“The roof features an underslung crane, requiring even tighter deflection tolerances than those needed for the 165m long rolling hangar doors each side.”

As well as a state-of-the-art hangar, the development will also comprise of a workshop, and office space and 650,000 sq. ft of apron area and surrounds. It is being made of 1600 tonnes of steel and 300,000 sq ft of cladding. It is due to be completed in 2022.

REIDsteel is providing conceptual and detailed design, fabrication and erection of both the steel frame and the full building envelope including cladding, windows, doors, decking and vents.

Tonbridge-based Civils provides construction services across a wide variety of sectors, including industrial buildings, health and medical centre development, car parks, hangars, stores, commercial units and residential property.

A video showing progress at the development can be viewed here.