The planning of the works was produced in accordance with the client as Lawson Group sent their method statements and health and safety plans to the CDM coordinator for approval. The asbestos removal in F Block was three months’ worth of work, removing asbestos insulation board and undertaking an environmental clean of the building.
For the first three phases, the demolition work commenced in phase one and worked its way down the hill entering into the new phases once each one had been completed. After the demolition of every phase, the demolition arisings were crushed to a 6F2 specification in agreement with the client so they could be reused as a sub base.
Phases four and five of the complex consisted of the original buildings that were built on the site in the 1950’s.
The demolition of M Block required the use of Lawson Group’s Liebherr 954 excavator. The height of the extendable arm was utilised to its full extent of 26m to reach the top of the atrium roof. A four-tonne scissor attachment was used at the end of the arm in order to cut through the heavy steel framework of the building.
The building’s outer shell was divided up into three sides by the existing three, very large tower blocks which were reinforced into the building.
The methodology of this building was therefore broken up into three sections, starting on one side and gradually demolishing the building – ensuring that the correct procedures were made to avoid the building collapsing.
The towers were demolished in turn. It was asked by the client to keep an outline structure of the base for one of the towers. This was because it was planned to be kept and installed as part of the design of one of the new buildings to be built.
The project required eight of Lawson Group’s fleet of machines including the CAT 374 which was bought specifically for GCHQ and other secured works.