The traditional buildings of Wales relied heavily on the use of timber as a building material with the dominant form of construction being the cruck-truss.
The cruck-truss consists of a pair of curved oak crucks set in the shape of an ‘A’ and crossed at the apex to form forks to support the ridge-piece. In Wales we have over 800 surviving cruck buildings. However, they are relatively rare in south-east Wales.
Cruck-truss construction was gradually superseded by the box-frame, built up from a grid of vertical posts connected by horizontal tie-beams. The frame then supported the triangular roof trusses, made up from separate pieces of timber.
Croft Farm Barn is noted as illustrating the introduction of framed principals in a cruck-trussed structure, a development that had already been utilized in wooden houses, “gradually changing from an old-fashioned to a new-fashioned technique.”