Mathematical tile

Mathematical tiles are a building material used extensively in the southeastern counties of England—especially East Sussex and Kent—in the 18th and early 19th centuries. They were laid on the exterior of timber-framed buildings as an alternative to brickwork, which their appearance closely resembled. A distinctive black variety with a glazed surface was used on many buildings in Brighton (now part of the city of Brighton and Hove) from about 1760 onwards, and is considered a characteristic feature of the town's early architecture. Mathematical tiles had an extra price advantage during the time of the brick tax (1784–1850), although later there was a tax on tiles also.

The tiles were laid in a partly overlapping pattern, akin to roof shingles. Their lower section—the part intended to be visible when the tiling was complete—was thicker; the upper section would slide under the overlapping tile above and would therefore be hidden. In the top corner was a hole for a nail to be inserted. They would then be hung on a lath of wood, and the lower sections would be moulded together with an infill of lime mortar to form a flat surface. The interlocking visible surfaces would then resemble either header bond or stretcher bond brickwork. Mathematical tiles had several advantages over brick: they were cheaper, easier to lay than bricks (skilled workmen were not needed), and were more resistant to the weathering effects of wind, rain and sea-spray, making them particularly useful at seaside locations such as Brighton.

Various colours of tile were produced: red, to resemble brick most closely; honey; cream; and black. Brighton, the resort most closely associated with mathematical tiles, has examples of each. Many houses on the seafront east of the Royal Pavilion and Old Steine, for example on Wentworth Street, have cream-coloured tiles, and honey-coloured tiles were used by Henry Holland in his design for the Marine Pavilion—forerunner of the Royal Pavilion. Holland often used mathematical tiles in his commissions, although he usually used blue Gault clay to make them.

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