The trestle of a post mill is the arrangement of the main post, crosstrees and quarterbars that form the substructure of this type of windmill.[1] It may or may not be surrounded by a roundhouse. Post mills without a roundhouse are known as open trestle post mills.[2]
A trestle mill is a variety of smock mill, usually without weatherboards, formerly used for drainage in the Norfolk Broads.[3] Examples can be found at Horning,[4] Ludham[5] and St Olaves.[6]
A well preserved example of a timber crosstree, from the trestle of a medieval windmill, was excavated by archaeologists at Humberstone, near Leicester, in 2007.[7]