Gauged brickwork is the highest class of work available in brickwork. The arch, in this case, or other enrichment, must be accurately surveyed, drawn 1:1 scale, templets made, and the rubber bricks cut. These in turn must be perfectly squared on two sides before they are cut to templet size and rubbed accurately until they fit the drawing. The opening in which the arch is installed must be accurately set out before each arch can be constructed. Finally, when the arch has been constructed and has set, it is rubbed with a pumice stone and pointed up. Gauged work is perhaps among the most satisfying and fulfilling of all types of brickwork.
An example of a gauged arch constructed in the 19th Century as a replacement for original 18th Century work. It is badly decayed due to the use of hard cement mortars both above and in the arch itself.
Brickwork above the arch had suffered because of modern interventions and inappropriate materials which had then cracked and sagged. Water ingress and associated decay mechanisms affected the survival of the arch.
The openings are carefully surveyed, and a life size drawing produced using accurate geometry skills. Templets are cut and marked up for cutting the rubber bricks.
Often, arches can be prepared in the workshop but in this example the arches were cut and rubbed on site using a potting shed as a temporary workshop!
The decayed arch and brickwork above the opening is removed to allow access to construct the new arch. Here, a lintel is installed as these are flat arches. Camber arches, those with a very slight rise in the centre, would be built over a former and would be self-supporting. Accurate setting out is vital and the preparation of the existing brickwork to receive the arch is painstaking to achieve the right finish. Here a line is taken from the striking or vanishing point of the arch (taken from the drawing) to test and check the cutting of the angles of brickwork and the laying of the arch voussoirs. This arch has been designed with joints of 2mm.
Once the arch is drawn, templets are prepared to which bricks are squared, marked cut and rubbed until they fit the drawing exactly with the required joint width.
The voussoirs laid in lime putty mortar according to their positions taken from the drawing and accurately marked on the lintel or arch former. They are then checked using the line emanating from the striking point and a pre marked staff on top of the arch. Here the key brick is being laid to complete an arch.
Rubbing the face of an arch will remove all imperfections before the joint lines are revealed and pointed up carried out as required.
The brickwork above the arch has been reconstructed and laid to line prior to pointing up. Where possible, original bricks have been reused. Where inappropriate modern bricks had to be replaced, a 60mm soft handmade facing brick is used. The brickwork is reconstructed based on photographs of the original & pointed with an appropriate putty mortar and penny struck finish. No lintel is visible underneath the soffit because it is set back far enough for its edge to be covered by either the window trim or by pointing. Camber arches in whose soffits are visible on the other hand, must have a nicely finished soffit too.