The wall sits on an arch which spans new and original walls.
As it seemed likely the former would settle and the latter not, it was decided to build the wall using small masonry units and large lime-mortar joints.
The adjacent medieval random rubble wall offered a precedent but Warwick Pethers was reluctant to use it: the surface of such walls can disconnect from the core and, as he explains, 'it would have been impossible to emulate its accretive and weathered charm'.
The new wall has a brick core corbelling into and potentially supporting a surface zone of flints, 330mm (13in) deep to accommodate various shapes and sizes of flints. The mechanical bond thus created avoids the need for steel ties.
It was clear that the surface pattern of flints would reflect the brick corbels behind and it was decided to articulate this with a diaper. A trial wall established how dark the diaper flints needed to be and how best to know when to lay one. To achieve a wall without voids, brick and flint had to be built up together, but this meant the craftsman had to rely almost entirely on the brickwork plans.
The wall was built without a hitch. This, to Pethers, is 'an illustration of what can be achieved where much is expected of the craftsman - foolproof details mean that eventually only fools are required to implement them'.