Fig. I: Alliance Assurance mosaic roundel. and formed a feature of the Alliance Assurance Building, High Street, Shrewsbury. It depicts a castle on a rocky promontory, symbolic of the stability of the company. It is fairly certain that the mosaic was made by Maw & Company, Jackfield. It was rescued from imminent demolition by Tony Herbert in 1975 and placed in store at Jackfield Tile Museum until 1990, when it was decided to restore the mosaic for display in the Museum. The mosaic is comprised of ceramic tesserae of many different colours and sizes; the sizes range from 3 mm square to 14 mm square, and pieces are often cut to specific shapes which form an integral part of design, particularly on the castle itself. The tesserae were bedded on 3 cm-thick concrete which was crisscrossed randomly with steel strengthening strips. These had corroded and expanded causing the mosaic to break apart. The mosaic was broken in a number of places, and many of the tesserae were loose, though only a few were missing. Treatment began by covering the face of the mosaic with strong double sided sticky tape, 8 cm wide. This was chosen because it was removable with water, but strong enough to hold for the limited time required for work on the mosaic. It also had the advantage of being transparent if the backing paper was peeled away; this allowed easy viewing of the complex pattern when required. Once all of the tesserae had been secured in place, each broken section of the mosaic was turned face down onto plywood boards, clamped to a workbench and all of the steel bars removed by cutting into the concrete with a small angle grinder fitted with a stone cutting disk. The mosaic had to be cut into manageable sized sections; this was done by cutting vertically into the concrete until the backs of the tesserae were visible. It was then possible to separate the sections by hand at the same time as carefully cutting the sticky tape around the shapes of the tesserae with a scalpel. I found it preferable to allow the sections to be random in shape, following the dictates of the design. It was then reasonably easy to remove the concrete from the back of the mosaic sections by means of a vertically mounted bench diamond cutting saw. Once the concrete was removed, each section was lifted (still taped on the face), and placed face down on a large piece of 1 cm-thick CONTEXT 52 plate glass. The mosaic was gradually reformed in reverse; this was quite a lengthy process. The mounting and finishing off was relatively simple. The whole mosaic was surrounded with a 10 cm-high wall of flexible Perspex. Onto the back of the mosaic, plaster was poured to a depth of 5 cm. This was done in two stages to allow a layer of fine plastics mesh to be placed in the plaster. When the plaster was dry the whole mosaic was turned, and the tape removed. I used a mixture of Polyfilla, pva emulsion and water mixed to a smooth paste as a grouting mixture as I felt that this would give added adhesive strength between the very small tesserae. The small amount of missing area was filled with plaster and painted to match with acrylic artist colours. The face was then waxed with Renaissance"wax. It should be pointed out that any cutting tool should only be used by individuals trained in their use. RESTORATION IN SITU As a result of a change to the pattern of visitor flow and an increase in their number, the Entrance Hall Mosaic (Fig.2) of Jackfield Tile Museum had, over a period of two years, gone into a rapid decline in its condition. Steel strengthening bars which had been placed within the original concrete bed of the floor had corroded and expanded, causing bubbling of the surface, severe crumbling and in some parts loosening of the tesserae. I decided to lift sections of the mosaic which were small enough as to be manageable, approximately 40 cm square, or following the dictates of the design, and to lift no more than three sections at any one time. Tapping all over the floor area with a small rubber mallet highlighted the areas where the tesserae were not fixed to the bed. A hollow sound indicated if this were so. Each section was taped up, as in the previous project, the grouting around the edge of each section was loosened either by hand or using a cutting tool, depending on how solid it was, and then each section was lifted and placed face down onto plywood boards in one move. A useful tool for this process proved to be roofing tiler's 'hook'. Any tesserae which were firmly fixed to the bed were left in place. The corroded steel strips were removed. The concrete bed was ground back by approximately 5 mm, to allow space for new adhesive. The sections were taken, face down on plywood boards, to the workshop, where all loose grouting and old cement were removed. They were then covered with a layer of floor tile adhesive in which was placed a layer of plastics mesh. When dry the sections were turned, the tape removed from the face and sections cleaned of any remaining loose debris or dirt. Each section was then returned to the hall and repositioned onto a bed of modern tile adhesive. Missing areas were replaced with new matching tesserae and the whole floor was grouted with tile cement. High quality tile cement was used throughout to provide the strength and stability needed in a high traffic area. HOLDING OPERATION The mosaic floor in the entrance porch of St John the Baptist Church, Whittington, is grey marble and a yellow stone. Much of the marble had
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