A simple square building on a single level.
The wall height is raised increasing the roof height enabling a floor to be inserted. The building is enlarged with the wall plate continuing across to the new bay which is built two storey in height and has a lower floor level than the existing building. A new central roof truss is built and the original truss here is removed, the timbers probably reused in the new truss as it is very similar in style and size. A chimney is built, probably at the same time, behind the new central truss.
The original part is shown in black, new timbers in red and removed timbers in green.