Cellular fired clay blocks - Ziegel blocks from Germany (U = 0.31W/m 2K) - are precise enough to be laid thin-bed and have no mortar in the perpends, though there is some mechanical interlock. They provide a straightforward single-leaf wall, without cavity or added insulation layer. The external lime render is a proprietary sprayed system applied by Ziegel. With the longer spans of this 50-seat (in bent ply) theatre, the roof is supported on Glulam beams. The roof finish is a single-ply membrane (sedum was costcut here and for the timber pavilion). Discreet wind catchers and the heavyweight walling are so far keeping room temperature well under control. A clay plaster (Claytec) was used on the exterior within the main pavilion, but was felt to be too soft for the lecture theatre interior itself and lime plaster has been used there.