Case study - private housing
Lye corner house
The clients' brief to the architect will be familiar: "as large as house as possible with the minimum budget'. The architect's response was to limiting the amount of space lost to circulation, using a spine wall splitting an L-shaped plan. By stepping through the spine wall, occupants cross from room to room and double height areas mean even the smallest hallway does not feel pokey. First floor is accessed by a gallery suspended off the spine wall and additional bed and storage decks are hung off the wall. There is a 400 mm differential between levels in the building which means the apertures also frame views from the higher kitchen and hallway area out to the garden through the living areas. 
The wall has huge wind loadings which challenged lightweight construction methods. The clients were in any case keen to see the spine wall built in a heavier construction material because they were anxious about potential overheating with so much south facing glazing. However, with so many trees in close proximity they were also anxious about maintaining painted concrete or painted render.
Separately they had been inspired by the recent renovation of the white brickwork at the nearby New College in Cambridge and set about sourcing something similar. The Gima block which offers 100% protection against damp and moss build up was chosen because it was available in both white and black. The choices are ideal for referencing both the white render of a majority of houses in this area of Essex and also for creating the brickwork plinth, which is normally black painted local brick whether under rendered, brickwork or timber clad building.
The design team were also attracted to exposed brickwork as no-maintenance material both inside and outside. This is a growing family with highly destructive children and the prospect of surfaces able to deal with knocks was compelling. Every room of the house has a least one wall faced in the white block, usually the largest which has helped to reduced the amount of time spent on drylining and painting the larger expanses.
Stackbonding the blocks without lintels would have been impossible with normal mortar. Here the apertures appear like machine cut holes to the white wall, specials being created for the headers and jambs of each aperture so that the white clay forms a neat reveal all the way round. The clients like the reveals so much they are currently avoiding fitting doors.
Structural masonry system
Aesthetic and structural requirements of the design brief called for large clay stack bonded fair faced masonry constructed as a supporting spine wall. This presented a number of problems, not least of which is the fact that stack bonded masonry has low lateral strength properties. In addition the spine wall is designed as a cantilever - the lightweight timber structure does not allow such a wall to be "propped" at the top.
The solution has been to build a true cantilever diaphragm wall using high strength adhesive thin joint mortar which compensates for the strength loss in stack bonding. Additional lateral restraint to the spine wall is provided by post tensioned aggregate blockwork which is also constructed using a high strength adhesive.