We welcomed Michael Hammett on St. Valentine’s Day to talk to us about bricks. Prior to retirement, Mike was a senior architect at the Brick Development Association (which represents UK brick manufacturers) he was responsible for technical guidance on the design and construction of brick masonry. He is currently an active member of the British Brick Society, a history and archaeology group.
Michael explained the Romans’ contribution to building in Brick. The Romans made large bricks which measured about 18 inches square and about 1½ inches thick. So, from 43AD until 412AD, the Romans introduced the use of brick in England, Scotland and Wales. However, after they departed, bricks were no longer manufactured here. Bricks were still used, but only those taken from buildings built by the Romans. You can see even today many examples of Roman bricks in our churches (St Albans Abbey/Cathedral).
Around 1160AD ‘native bricks’ started to be produced. These were known as Great Bricks as they measured about 12″ x 6″ x 4″ (modern British Standard is 8 5/8″ x 4 1/8″ x 2 5/8″ – but now metricated). During the 14th Century, probably due to increased trade from the forming of the Hanseatic League, brick technology was imported into eastern ports in England. Hull and Beverley in Yorkshire became important brick towns with Municipal brickyards being established in Hull in 1303.
In the early 15th century various halls and castles started to be constructed in brick (Tattershall Castle in Lincolnshire and Faulkbourne Hall in Essex). Such buildings were often constructed using bricks made on, or near to, the site of the building.
Bricks were being made individually and were expensive and, therefore, were only the domain of the rich.
Clay near the surface was dug up and weathered over the winter. It was then mixed with water and ‘plugged’ (well mixed, often by feet). ‘Pug Mills’ powered by horses replaced this labour intensive procedure and later machines replaced the horses. Clots of the mixed clay were dropped in sanded moulds and the excess removed. The bricks then needed to dry out over 6 weeks, or so, and once dry enough, they were fired in ‘a clamp’, or ‘a kiln’. A clamp was a body of bricks set on a bed of fuel, encased by previously fired bricks to conserve heat. A large numbers of bricks could be fired in a clamp, but once lit, the firing could not be controlled and the quality could not be guaranteed.
A kiln allowed heat to be controlled and the bricks to be fired to a more regular standard. Brick firings used firstly wood, then coal or coke and then oil or gas, as fuel.
Gradually more buildings were constructed in brick, especially following the Great Fire of London in 1666 (wooden buildings were vulnerable to fire). To satisfy the demand, London Stock bricks were made in their millions; additions of ash, or and chalk, to the clay, created their characteristic colouration.
In the 19th century great demand for bricks stimulated the exploitation of deep lying clays and machine manufacture. Clays from Fletton (Peterborough) were discovered to have their own fuel within and, once heated, they fire themselves! This resulted in great cost savings and the working of similar clay in the Bedfordshire, Northamptonshire and North Bucks formed a major sector of British brick production.
Today, traditional brickmaking methods are still used by some brickmakers, but the bulk of production uses machines to extract the clay, mix it and form the bricks by pressing or extruding and wire–cutting. Firing is done in huge continuous burning kilns that can complete the process in 3½ days.
So, look up and see the history around us present in our buildings; it may surprise you!