Scoria Blocks – The Origins of Eco-Friendly Paving
Innovation Born from Industry
Scoria bricks, also known as brick pavers, are a striking silvery-blue paving unit made from steel slag, a byproduct of the steel-making process. The term “scorio” is derived from the Greek word “scoria”, meaning excrement or waste—aptly describing the molten rock-like slag used in these bricks.
In the mid-19th century, Joseph Woodward patented a machine to manufacture these blocks at his Teeside Scoria Brick Company. Molten slag was transported by train directly from nearby blast furnaces to his factory, poured into moulds, and left to cool into solid units. The success of this process was so great that Woodward went on to open several more factories, all strategically located near steel foundries. His pioneering approach not only prevented millions of tons of industrial waste from going to landfill but also laid the foundation for one of the first sustainable block paving methods in Britain.
My own first memories of Scoria bricks came while working on a drystone walling project in Marsden, Yorkshire. A pile of stone I had delivered included several of these unfamiliar blocks. Assuming they were granite, I split one open—only to be met with the overwhelming stench of rotten eggs from the sulphur trapped inside. The sulphur smell lingered for hours and could be detected up to 10 metres away.
Built to Last
Scoria bricks were typically laid over a base of compacted stone or steel slag, with a sharp sand laying course. Each layer was compacted with rollers and tamped using large wooden hammers by hand crews. This installation method shares notable similarities with today’s block paving techniques.
What truly set Scoria apart was its strength and resilience. With ultra-low water absorption and high resistance to frost, chemicals, and weathering, these pavers proved incredibly long-lasting. Their endurance saw them exported as far as Canada, Belgium, and South America—and many still remain in place today across the UK.
Despite their durability, Scoria bricks fell out of favour with the rise of the motor car, as passengers demanded smoother and quieter surfaces. The textured surface could also be slippery, particularly in wet conditions.
A Legacy with Modern Potential
Even though their widespread use has diminished, Scoria’s eco-credentials and historical significance keep them relevant. Some reclaimed units can still be sourced from specialist yards, and many experts believe a modern, slip-resistant version could see Scoria return as a truly sustainable paving solution.
