One-brick walling – that is to say, walls that are one brick (215mm) thick – are no longer used for the external walls of houses and domestic buildings. Instead, their use tends to be limited to garden walls, retaining walls and boundary
walls. Some bricklayers still refer to wall thicknesses in imperial terms, so one-brick walls are sometimes called ‘9-inch walls’ and half-brick walls ‘4^-inch walls’, based on the old brick sizes.
Stretcher bond has an inherent weakness in one-brick walling, due to the continuous vertical ‘collar joint’ that runs the full height of the wall between the front half-brick thickness and the back half-brick thickness. In some instances, one-brick walls are still built in stretcher bond, with the strength issue (or rather the lack of it) being addressed by treating the wall like a cavity wall. A 10mm cavity is left in between the two skins of stretcher bond, which are then tied together with short cavity-wall ties. For advice on the principles of cavity walling, see Chapter 11.
The stronger bonds used for one-brick walls make use of headers that are laid through the thickness of the wall in order to give the wall greater strength and improved load distribution through both height and thickness. The most common bonds for one-brick walls are English bond and Flemish bond which, due to the introduction of headers, are quarter-lap bonding arrangements.