Building 79 (Mt Group)

Building 79, part of the MT Group, is an aircraft workshop complex constructed between 1935 and 1936. Designed by A. Bulloch, who served as architectural advisor to the Air Ministry's Directorate of Works and Buildings, it showcases a successful blend of functionality and aesthetics characteristic of the early phase of the RAF’s post-1934 expansion. The building is constructed with bath stone ashlar facing brick or blockwork, featuring profiled tile roofing and tall square stacks.

The layout comprises two long, hipped service sheds in parallel, intended for airframes and engines, with a lower, mainly top-lit flat-roofed unit in between. This central section houses offices, stores, and an Instrument Repair Shop.

On the northwest front, facing the hangars, are full-height sliding and folding doors to each workshop shed, set one bay forward from the central section. This central section incorporates a high, flush-coped parapet concealing roof lights, a central door with an overlight, and a single-light and two-light casement window on each side, all aligned under a lintel band. The returns to the southwest and northeast sides each feature seven large, three-light casement windows, with the end lights separated from the central group by downpipes terminating in hopper heads. The southeast front is similar to the northwest, but a doorway has been partially blocked and an additional doorway has been added to the left; the workshop bays project further and have two-light casement windows on the inner returns.

The interior retains original panelled and sliding doors. The main repair sheds have steel roof trusses and a plain concrete floor; one shed contains an inspection pit.

The building is historically significant as one of a group of largely complete technical structures at a nationally important RAF site, demonstrating the improved architectural quality of air bases developed after 1934. It provided repair and administrative facilities for the Aircraft Storage Unit. Hullavington airfield, opened in June 1937 as a Flying Training Station, exemplifies the architectural standards of this period and was later selected in 1938 as an Aircraft Storage Unit.