Why brick is a better calendar than you might think

Brick is one of the most eloquent materials in the British landscape. It records fashion, taxation, transport and technology in every course. A façade can be original, refaced, patched or rebuilt, and the bricks often tell you which. No single clue gives a date on its own, but size, bond, colour and context together narrow the field. Start by standing back, then move in close.

Brick sizes: the taxman's fingerprint

Before the late eighteenth century, bricks varied enormously. Tudor and Stuart bricks were often about 9 by 4½ by 2¼ inches (roughly 230 by 115 by 57 mm), but locally they could be smaller or wildly irregular. In 1784 the government introduced a brick tax, charged per thousand bricks. Manufacturers responded by making each brick larger, so fewer were needed. A late Georgian or early Victorian wall may therefore contain bricks 9½ to 10 inches long and nearly 3 inches thick. The tax was repealed in 1850, and sizes gradually settled towards the familiar 8½ by 4 by 2½ inches (about 215 by 102 by 65 mm).

Measure ten bricks in an unobtrusive area, including the mortar joints. Noticeably long, thick bricks suggest 1784–1850; slimmer, uniform bricks suggest later. Regional exceptions abound: London stocks, gaults and Flettons all have their own habits. Always measure away from repairs.

Bond patterns: the grammar of the wall

The way bricks are laid is called the bond, and it changed with fashion and structural need. English bond alternates whole courses of headers and stretchers. It is strong, old-fashioned and common from Tudor times into the early Georgian period. Flemish bond alternates headers and stretchers within each course. It became fashionable in the late seventeenth century and dominated polite Georgian façades, often with darker headers creating a chequered effect. English garden wall bond uses three or four stretchers to one header and is typical of eighteenth- and nineteenth-century houses, cottages and garden walls. Rat-trap bond stands bricks on edge to form a hollow wall; it appears from the late eighteenth century onwards.

By the nineteenth century, stretcher bond — all bricks showing their long faces — became common, especially once cavity walls arrived. A solid brick wall in stretcher bond is usually later than one in English or Flemish bond, though it can be a later extension or refacing. Look also at the side and rear elevations. Builders often saved the best bond for the front.

Colour, texture and firing: reading the kiln

Early bricks were fired in clamps, temporary stacks with fuel mixed in. The heat was uneven, so colours varied wildly: reds, browns, purples, yellows and blues could appear in the same wall. Underfired "place bricks" were soft and pale; overfired "burrs" or vitrified headers turned glassy blue-black. London stock bricks, made from brick earth and ash, are yellow-brown and speckled, often laid with black headers in Flemish bond. Gault bricks from the Cambridgeshire area are pale cream or yellow. Suffolk whites and Staffordshire blues are other regional signatures.

From the mid-nineteenth century, kiln firing and machine moulding produced more uniform bricks. Victorian builders also enjoyed polychrome effects, banding red, blue and buff bricks. Colour alone is unreliable: soot, paint, render and cleaning all alter it. Tuckpointing, where coloured mortar imitates fine joints, can make a plain wall look more refined than it is. Use colour as a supporting clue, not a verdict.

Alterations, refacing and the tell-tale joints

Many British houses are palimpsests. A Tudor timber frame may wear a Georgian brick front; a Victorian terrace may hide an earlier cottage. Look for straight joints, where one wall butts against another without interlocking. Look for toothing, where bricks project in a saw-tooth pattern, ready for a wall that was never built or was later removed. Changes in bond, brick size, colour or mortar across a façade suggest different campaigns. Plat bands, string courses and gauged brick arches can all be later insertions.

Mathematical tiles are a subtle trap: glazed tiles shaped like bricks, often black or red, used from the late eighteenth century to reface timber-framed buildings. They can look like brick from a distance. Bricked-up windows leave arches, keystones and a change in bond. A rendered or painted façade hides everything, so inspect the side or rear, where original work is often left exposed. Reused bricks, with old mortar clinging to them, usually indicate a later wall built from earlier material.

A practical walk-round method

To date a façade sensibly, work through these steps:

• Step back. Note the overall proportions, roof line, chimneys and storeys. A polite Georgian front often sits behind a shallower roof than a Victorian one.
• Scan for joints. Walk the length of the wall and mark any straight joints, changes in level or obvious patches.
• Measure bricks. Record brick length, width and course height in at least three places, avoiding repairs. Include the mortar joint.
• Identify the bond. Check the main façade, then the sides and rear. Note whether the bond changes.
• Study colour and mortar. Look at vitrified headers, speckling, tuckpointing and the width and softness of the mortar. Lime mortar is usually pre-twentieth century; hard cement is later.
• Cross-examine. Compare your findings with maps, deeds or local knowledge if you have them. The bricks give you a range, not a precise year.

A historic brick façade is an honest witness, but a forgetful one. It will not give you a single date. It will give you a story of fashion, tax, transport and repair, and that story is often more interesting than the year alone.