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Mar 2026
Ardmore Construction – The Old War Office Restoration

Project Overview

CA Drillers were appointed by Ardmore Construction to support the prestigious restoration of the historic Old War Office, located in the heart of Westminster, London. The building is one of the capital’s most iconic heritage landmarks, requiring specialist construction techniques and careful planning to preserve its historic integrity while enabling modern redevelopment.

During the most demanding phases of the project, CA Drillers deployed a workforce of up to 60 skilled operatives, delivering a wide range of specialist services including diamond drilling, controlled demolition, structural cutting, and builders’ work openings.

Scope of Work

The Old War Office restoration involved a diverse range of technically complex tasks across multiple levels of the building.

Basement & Structural Works

CA Drillers carried out diamond drilling operations to create large sump pits within the basement areas, supporting drainage and building infrastructure requirements. The team also utilised Brokk robotic demolition machines for controlled break-out operations, enabling efficient concrete removal in confined areas.

Core Drilling for Building Services

Within the swimming pool area, CA Drillers completed precision core drilling works to accommodate lighting installations. These works required careful execution to ensure the functional and aesthetic requirements of the redevelopment were met.

Builders’ Work Openings

The team also formed multiple builders’ work openings (BWIC) throughout the structure. This was achieved using hand saws, diamond track saws, and stitch drilling techniques, allowing precise cutting while preventing overcutting in structural elements.

Following the formation of these openings, lintel installations were carried out across all levels to reinforce the building’s structural framework.

Rainwater Pipe Formation

A particularly complex task involved forming new rainwater pipe routes throughout the building. The process began at the roof level and continued through walls and slabs down to the fourth basement level, requiring extensive cutting and breaking works across multiple floors.

Electrical Conduit Chasing

CA Drillers were also responsible for the chasing of electrical conduits across ceilings, walls, and slabs throughout the building, allowing the installation of modern electrical systems within the historic structure.

Wire Sawing of Bomb-Proof Walls

One of the most technically challenging elements of the project involved the wire sawing removal of steel-plated bomb-proof walls that surrounded the building. Due to the reinforced nature of these walls, advanced cutting techniques and specialised equipment were required to safely remove these structures.

Health & Safety Measures

Given the sensitive nature of the historic site, strict health and safety measures were implemented across all work areas. These included:

  • Full tent enclosures for controlled working environments

  • Chapter 8 safety barriers to clearly demarcate work zones

  • Dust cube extraction systems to minimise airborne dust and maintain safe conditions

These measures ensured the safety of workers while protecting the historic building fabric.

Project Outcome

Through advanced cutting techniques, specialist equipment, and a highly skilled workforce, CA Drillers successfully delivered a wide-ranging scope of works across the Old War Office restoration project.

The team’s expertise enabled complex structural modifications while preserving the architectural integrity of this historic landmark.

Conclusion

The Old War Office project demonstrates CA Drillers’ capability in delivering large-scale, technically complex construction works within historic and heritage environments. Their contribution played a key role in the successful restoration of one of London’s most iconic buildings, ensuring the preservation of its historic significance while preparing it for modern use.

Old War Office                  Old War Office

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