Collection of files created by both the Maintenance Department and Engineering Department responsible for building maintenance and repair. The files cover various projects to either alter, refurbish or create new test facilities at the Barton Road site, previously run by Metropolitan-Vickers Electrical Co Ltd. New build projects included erection of Mechanical Laboratory, Irradiation Laboratory and High Bay along with alterations and refurbishments to Sub-Station, cooling water mains renewal, Producer Gas Turbine House and several other smaller projects.

The material contains day to day correspondence between departments at the company as well as between various contractors hired to carry out work. Documents also include estimates for various projects along with specifications and drawings for the work to be carried out.