Mountbatten House

Refurbishment of a unique post-war listed office building

In 2015, Historic England recognised Mountbatten House as one of the country’s 15 most important post-war office buildings. The Grade II listed six-storey complex was designed by Arup Associates’ Peter Foggo in the 1970s. Our engineers worked on the structural, civil and conservation engineering for its refurbishment.

Massively ahead of its time, the design incorporates landscaped terraces with planting flowing over stepped-back facades. The refurbishment architectural intention was low-intervention Cat A office refit, involving minimal structural interventions but requiring a thorough understanding of the structure.

The as-built structure employs a system of precast cruciform columns, girders and thin panels to form coffer pyramid structural bays on a 7.5m x 7.5m grid with a holorib slab on top, providing a neat solution for routing services while leaving an exposed soffit. We conducted structural investigations into the condition of the existing concrete and its reinforcement, validating critical parts of the proposals against the substantial volume of archive drawings made available to us.

Works include creating new openings in existing floor plates, inserting mezzanine floors, reconfiguring the reception area with new localised double-height bays, and designing the support for the feature timber-clad spiral staircase linking reception to level two. We were responsible for designing connections for new elements to the existing structural fabric, including complex bespoke connections to the existing cruciform columns.

We played a crucial role in informing contractors and the design team on the structural principles and behaviour of the existing structure, advising on the feasibility of the proposals and required alterations, and ensuring relevant risks were understood and mitigated at all stages.