former cart-shed at Great Nast Hyde House, Wilkins Green Lane, Hatfield, Hertfordshire, prior to and during alterations to the buildings. The barn was found to consist of an interesting structure of mid-19th century date, comprising a timber-framed threshing barn over a high brick dwarf wall and rising to a hipped roof. It is of five bays of regular and systematic construction with opposing apertures marking the central bay, the timber-frame following a pattern of primarybraced studwork and a simple side-purlin roof with raking struts. There are two points of particular interest; the barn reuses much timber from an earlier, perhaps 17th century building but the new timber used at construction is imported Baltic softwood. This is demonstrated by the presence of scribed markings that include Arabic numerals but also the port mark of Gdansk utilised as part of a bracking system for demonstrating the quality of timber. The cart-shed by contrast is relatively straightforward and its brickwork suggests a late 18th or early 19th century date for construction, but even here there is some interest where the brickwork, though clearly contemporary, is laid in Flemish bond at lower level with rat-trap bond above.