Case Study: The Bank House, Southminster

The former Barclays Bank located at The Bank House, 10 Station Road, Southminster, has undergone a significant transformation. Originally a mix of residential and office spaces with a dated flat-roofed extension, the property has been converted into a series of residential flats. The project included alterations to both the original 19th-century structure and the construction of a new two-storey extension featuring a traditional design with a barrel-vaulted section at the rear.

GC Robertson was engaged to provide structural engineering services, focusing primarily on the foundation and superstructure design for the new extension. This case study highlights the structural solutions provided to support the architectural vision of blending contemporary additions with the building’s historical fabric while addressing the complexities of the site and ensuring compliance with modern building standards.

Foundation Design: The conversion project required the demolition of a single-storey rear projection and the construction of a new two-storey extension. Our structural engineers needed to ensure the new foundation system could support the increased load of the extension, especially considering the mix of old and new construction. The existing soil conditions in Southminster and proximity to adjacent buildings, including the Grade II listed Hermistone building, required a tailored approach to foundation design. This involved careful assessment of the ground bearing capacity and the implementation of a foundation solution that minimized impact on neighboring structures.

Superstructure Design: The superstructure of the new extension was designed to harmonise with the original 19th-century building, yet also support modern living spaces. The flat-roofed, single-storey section was replaced by a more traditional-looking, two-storey extension with a barrel-vaulted roof at the rear. The structural system incorporated steel framing for the vaulted roof to achieve the curved design, which presented challenges in load distribution. By using steel in combination with masonry, the design maintained aesthetic continuity while ensuring structural stability.

Load Bearing Walls: The alterations to the original building included internal changes to accommodate the layout of the new flats. As part of this work, existing load-bearing walls had to be assessed for their capacity to support additional loads from the new extension. Where necessary, we designed reinforcement and specified new steel beams to redistribute loads and avoid overloading the existing structure.

Roof Structure: The barrel-vaulted roof at the rear posed unique structural challenges due to its curved form. We provided detailed calculations and design for the roof trusses and supporting beams, ensuring they met all regulatory requirements while delivering on the architectural vision. The use of modern materials combined with traditional masonry provided the necessary support while maintaining the historical character of the property.

The structural engineering solutions provided by GC Robertson ensured that the conversion of The Bank House into residential flats was completed successfully, meeting both aesthetic and functional requirements. The new foundation and superstructure designs supported the blend of contemporary and traditional architectural elements, ensuring the long-term durability of the extension. Additionally, by addressing structural challenges associated with integrating new construction with a historical building, we helped preserve the character of the Southminster Conservation Area.

This project exemplifies how modern engineering can enhance the value of heritage properties while meeting the demands of contemporary living. GC Robertson is proud to have contributed to the successful transformation of this iconic building.