In masonry, toothing stones are stones or bricks that are left projecting from a masonry wall so that later pieces can be bonded into it. They form a (usually vertical) line of projections intended to interlock with a future wall or extension. If the addition is never built, the exposed stones can provide evidence of uncompleted plans for buildings archaeology.
Construction Toothing stones can be left in alternate courses, the horizontal layers of a wall. This allows a later continuation along the same line to bond with the existing masonry. The term toothing also describes cutting back part of existing masonry to form a joint with new work.
In historic construction, toothing was also used in external walls built in several leaves, with projections left to bond with an outer facing. Where the intended facing was a decorative façade that was never completed, the projections remained exposed. Examples occur on unfinished brick church façades in Italy, including that of the Church of the Suffragio in Rimini.
Historical terminology The term tusses occurs in the building contract for Catterick Church in Yorkshire, which required the mason to leave projecting stones for a future vestry. In his 1838 architectural dictionary, John Britton explained the term by reference to the stones' resemblance to teeth or tusks. He recorded tushes as a name still used in parts of England, and toothing as the equivalent London usage.
In German, these projections are called (literally, 'waiting stones'), also or , and sometimes . The historical Austrian term was .
Evidence of building history At Koło Castle in Poland, toothings helped researchers distinguish stages of construction and changes to the planned walls. The residential tower had toothings prepared for perimeter walls. On its eastern side, the later wall matched the intended thickness of ; on the western side, the wall was thick and overlapped the prepared toothing. Elsewhere in the castle, the joints between walls and toothings helped establish the sequence in which the south-western tower and adjoining curtain walls were built.
Toothing stones have also informed reconstructions. During preparations to rebuild the King's House in Brussels, found them in the façade. He considered them alongside an early 16th-century report mentioning a tower and gallery. This evidence influenced his decision to add two levels of galleries and a central tower to the reconstructed building, work on which began in 1876.
Toothing left for future construction should be distinguished from similar-looking projections left when an adjoining part of a building has been demolished, particularly in ruins.
Examples
See also Joint (building)
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