150 years of the shiny slag brick that is a defining feature of the Tees Valley

“On Wednesday, some experiments in the matter of the construction of the new bricks – which are made out of slag – were carried out at the works of one of the most eminent firms in Cleveland,” said the report in the Echo’s sister paper.

This is the advent of the shiny, blue-grey scoria brick. The slag brick.

A typical Tees Valley back lane, lined with scoria bricks - this one is in the Eastbourne area of Darlington

It was called the “scoria brick” from the Greek word meaning “excrement or dung”. The Romans applied the word to the hot, dark lava wastefully tossed from the top of a volcano.

The blast furnaces of Middlesbrough produced huge quantities of scoria which was just tipped onto the boggy saltplains to build up the river walls until Joseph Woodward, who we think had run a boot warehouse in Priestgate, had the bright idea of pouring the molten slag into moulds, reheating it (or annealing it) and then tipping it out as bricks.

“Knowing what we know, we need scarcely say that the experiments were highly successful,” said the D&S. “Some who might have entertained doubts as to the practicability of Mr Woodward’s patent were fairly converted by what they saw on Wednesday. The fact is significant enough.”

They saw that slag bricks are almost unbreakable and they are waterproof.

They were used to line the earthen floors of the disease-ridden yards so that piles of effluent could be sluiced out, and they lined gutters so water would run away.

Navvies surfacing part of Marton Road, Middlesbrough, with scoria bricks in August 1902. Picture courtesy of Vintage Middlesbrough, by Norman Moorsom

Stockton bought the first consignment of slag bricks, and soon many of the earth roads of south Durham and the Tees Valley were lined with them – their durability meant that they could withstand the iron-rimmed wheels of horsedrawn carriages. In the late 1890s, Darlington ordered that all its yards should be lined with slag bricks for health reasons.

Having lined the Tees Valley, Mr Woodward exported. In 1912, 62,881 tons of scoria bricks – we reckon that equates to 11m bricks – were shipped from Teesmouth, with 37 per cent going to Canada and 36 per cent to the West Indies. Rotterdam is to this day lined with Tees Valley slag. Our scoria bricks are also to be found in Belgium, the US, South America and Africa.

Scoria bricks in Vane Terrace, Darlington, with the name of Mr Woodward's company, the Tees Scoria Brick Co, pressed into it

But when motor cars came along, drivers wanted a smoother ride than the brick streets could offer. Over time the major roads were tarmacked, and the scoria bricks survived only in the back alleys.

Mr Woodward’s company eventually went bankrupt in 1966 and was formally wound up in 1972.

A lane in the Eastbourne area of Darlington, lined with diamond-patterned scoria bricks

However, as his manufacturing processes had become more sophisticated, some of his scoria designs had become more decorative – his double hexagonal interlocking bricks are a joy to behold. They have become sought after as design features in driveways leading to the poshest houses in the area, proving the really is mortar these bricks than meets the eye.

WE are always keen to hear of scoria bricks – are there any unusual bricks or displays down your way? Please email chris.lloyd@nne.co.uk if there are.