The Grade-I listed Great Hall in Winchester, built in 1220 as part of the city's castle and remodelled in the fourteenth century, re-opens to the public on 23 May after a £300,000 lottery-funded restoration by Hampshire County Architects.
A major feature of the restoration was dealing with the hall's leaking roof. At an unrecorded date, the lower slopes had been stripped of their lead and given a new covering of tiles. While these were fixed with bronze pegs in excellent condition, the iron fixings for the supporting timber battens were badly rusted, which left the tiles in a precarious state. Given the removal of the lead, any rain that penetrated beneath disturbed tiles was directed under the gutters and on to the top of the Medieval walls. Earlier remedial treatment had addressed symptoms rather than the cause and so exacerbated the problems - for instance, making the stone parapet of the north wall unstable.
The hall has been re-roofed and the detailing corrected, but a large proportion of the existing tiles - a mixture of Medieval, seventeenth- century and Victorian - have been re-used, supplemented by salvage from demolished buildings. The lead covering was restored to the lower slopes, using cast, not modern milled, lead to avoid compromising the scale of the roof. The concrete was removed from the tops of the walls and gutters rebuilt to their original falls, while the inner face of the parapet was rebuilt using all the original flints and stones. Roof timber was treated by pressure impregnation and saturation spraying.
All the mortars used on the building are now based on lime (no cement), after consultation with English Heritage. Some exterior stonework was cleaned but only by gently brushing with cold water. Interior stains were removed with even greater delicacy, by spraying a mixture of calcite and water at a very low pressure.
Along with the restoration of the Great Hall, Hampshire County Architects has improved facilities for visitors by converting the ground floor of a nearby stone- and flint-faced building into a shop and interpretation centre. A long corridor tacked on to the rear of this building in the 1930s now serves as a gallery in which the history of Winchester Castle is told.