and their regularity of shape and colour. High-grade bricks were used for face work and lower grades were bought for use as internal bricks. Unfortunately it seems to have been common practice for a high grade brick to be broken in half so that it could be used twice, each end appearing as a header in the wall. The result of this parsimony was that the wall was deficient in bonding bricks, i.e. bricks tying the outer skin of brickwork back to the inner part of the wall, often resulting in the outer skin peeling away from the inner and bulging out. This issue, known as snapped or snap headers, leads to walls which need to be repaired either by rebuilding or by fitting various types of proprietary tie. Stock bricks The term 'stock brick' can either indicate the common type of brick stocked in a locality, or a handmade brick made using a stock. A stock or stock board is an iron-faced block of wood fixed to the surface of the moulder's bench. The brick mould fits over the stock; the brick maker fills the mould with prepared clay and cuts it off with a wire level with the top of the mould, before turning out the 'green' brick onto a wooden board called a pallet for drying and firing. Reclaimed London stock bricks are sought after for decorative and conservation use. The mortar usually used with them in original construction was lime mortar, which is much softer and weaker than modern cement based mortar and can be cleaned off second-hand bricks easily leaving them ready for re-use. Nevertheless, the supply of second-hand stocks cannot always meet the demand, and 'new' second-hand stocks can be obtained from builders' merchants. Unfortunately, some of the new products are painted white or black to simulate the whitewashed or soot blackened surfaces often encountered in the real second hand bricks – making them unsuitable for face-work. Mortar Most London stock bricks are more or less porous, as is the lime mortar in which they have traditionally been laid. The pointing should be flush pointing so that rain water can run down off the surface and not be encouraged to soak into the wall as is the case with recessed or struck pointing. When used in this way the brickwork does not get wet all the way through and is thus effectively waterproof. Lime