Temporary Works
Embassy Facility Refurbishment, London, UK
Project Brief
LSY Engineering Consultants Ltd was appointed as Lead Temporary Works Engineer for the refurbishment of an existing embassy building in London. The project involved extensive internal alterations, the removal of structural elements, the installation of new service routes, and below-ground excavation work within a constrained urban site.
Our role included the design and coordination of all temporary works required to facilitate the refurbishment safely and efficiently while maintaining the stability of the existing structure throughout the construction process.
Challenges
The project presented several significant engineering challenges, largely due to the age and nature of the existing building.
The embassy’s external masonry walls were approximately 1m thick and supported substantial structural loads. As a result, temporary works associated with excavation support and manhole construction had to be designed to accommodate significant surcharge loads from the adjacent structure.
A further challenge was the lack of accurate information regarding the existing internal structure. Much of the building fabric remained concealed during the initial survey phase, making it difficult to determine load paths, wall construction, and structural arrangements before intrusive investigations were undertaken.
The site was also heavily constrained, limiting access for plant, equipment, and construction materials and requiring careful consideration of the temporary works methodology.
Process
LSY coordinated an initial programme of trial holes and intrusive investigations to establish the existing structural arrangement and determine the depth and configuration of the existing foundations.
The investigations confirmed that the proposed excavation works would be undertaken in close proximity to the existing building foundations and that the temporary works system would need to accommodate significant building surcharge loads while maintaining excavation stability.
Due to the restricted site access, we developed a temporary works solution using timber waling beams and sheeted excavation support systems. The lightweight nature of the materials allowed them to be transported and installed within the confined site environment while maintaining the required structural performance.
For the internal alterations, several load-bearing walls were scheduled for removal as part of the refurbishment works. LSY designed a temporary support system comprising multi-props and steel needle beams, propped from the existing floor slab at three key locations. This arrangement provided a safe and efficient means of maintaining structural stability while permanent alterations were undertaken.
The project also involved the removal of an existing steel beam weighing approximately six tonnes. Following consultation with the contractor, it was agreed that the beam would be dismantled in 1m sections to overcome site access restrictions and minimise lifting requirements.
Detailed structural checks were undertaken to confirm that the remaining supporting structure could safely resist the temporary point loads generated during the phased removal process. This allowed the work to proceed safely without the need for additional extensive temporary support systems.
Throughout the project, LSY worked closely with the contractor and wider design team, ensuring that temporary works designs were practical, buildable, and fully integrated with the construction programme.
Outcome
The excavation and refurbishment works were completed successfully and ahead of programme. The use of lightweight timber excavation support elements enabled the contractor to overcome challenging site access restrictions while maintaining safe working conditions throughout the construction phase.
Similarly, the temporary needle beam and multi-prop support arrangements provided an efficient solution for the internal alterations, helping to reduce programme durations and minimise disruption to the wider project.
The successful delivery of the scheme demonstrated the value of early temporary works involvement and close collaboration between the engineering and construction teams.
As a result of the project’s success, LSY Engineering Consultants Ltd was subsequently appointed by the main contractor on a number of additional projects to provide temporary works engineering services.
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