The barn at Croft Farm followed the traditional layout of 5 bays, the central bay used as the threshing floor, two high doorways and undaubed wattle panels in the walls. The grade II* listing statement dates the barn as circa 1550. However, a recent dendrochronological report claims the timber used for the the frame was felled in the Spring of 1581 and it is likely that the barn was constructed later that year.
The original barn was probably completely timber-framed. The eastern gable (road side) was rebuilt in stone during the seventeenth century. The barn is currently four bays – it is likely that the original western bay has been lost, probably undermined by a stream that runs close by, and the gable has been rebuilt in more recent times.
The Croft Farm Barn was originally recorded in “Monmouthshire Houses” (1951-54), a study of the county’s vernacular architecture by Fox and Raglan, which includes a floor plan, elevation and photograph of the building. At that time the barn was known as the Barn at Great Trerhiw, Llantilio Crossenny. The photograph of the barn (the north elevation) clearly shows a low stone wall with horizontal timber boarding to the middle height, and wattle panels above. It was also noted that this barn is the only cruck-trussed barn showing the original framing of the entry and that, even though the uprights are substantial, they are comparatively thin. Fox and Raglan suggested that doors were not originally hung on either jamb, raising speculation as to how the floor was kept dry when used for grain storage. They also noted that stone roofing tiles had been replaced with Welsh slate. However, the original roof would probably have been thatched.
Croft Farm Barn is an historically important structure. There is clear evidence of its sixteenth century origins and the cruck-trusses show important examples of superior carpentry. It is also remarkable that some of the oak wattle infill panels have survived.