Scoria brick

{{Short description|Iron slag brick}}

{{Distinguish|Scoria}}

{{Use dmy dates|date=June 2024}}

{{Use British English|date=June 2024}}

File:Whitby Scoria Bricks 1.jpg]]

Scoria bricks{{efn|Sometimes spelled Scoriæ{{cite news |title=Patent Scoriæ Bricks |url=https://www.newspapers.com/article/northern-echo-patent-scori-bricks/148423079/ |access-date=31 May 2024 |work=Northern Echo |date=1 November 1873 |pages=1}} or Scoriae}} is a type of blue-grey brick made from slag, originally manufactured from the waste of the steelworks of Teesside, common across the North-East of England.{{cite news |last1=Walsh |first1=David |title=Scoria bricks: history at our feet |url=https://northeastbylines.co.uk/region/north-east/scoria-bricks-history-at-our-feet/ |access-date=31 May 2024 |work=North East Bylines |date=6 March 2022}}{{cite news |last1=Lloyd |first1=Chris |title=The almost unbreakable slag bricks which lined the streets of the Tees Valley |url=https://www.darlingtonandstocktontimes.co.uk/news/20001616.almost-unbreakable-slag-bricks-lined-streets-tees-valley/ |access-date=31 May 2024 |work=Darlington and Stockton Times |date=20 March 2022 |language=en}} The bricks were also exported around the world and can be found in Canada, West Indies, Netherlands, Belgium, United States, India and South America.{{cite web |last1=Lloyd |first1=Chris |title=There's mortar bricks than meets the eye |url=https://www.thenorthernecho.co.uk/news/3206104.mortar-bricks-meets-eye/ |website=The Northern Echo |access-date=31 May 2024 |language=en |date=14 July 2008}}

The word Scoria originally comes from Greek, meaning "Excrement", but came to be used by the Romans for a kind of volcanic rock. The bricks were invented by Darlington industrialist Joseph Woodward, in the 1870s, with him registering a patent in 1873 and forming the "Tees Scoriae Company" the same year.{{cite news |last1=Lewis |first1=Stephen |title=York's back alleys in the spotlight: who designed those distinctive bricks? |url=https://www.yorkpress.co.uk/news/24263598.yorks-distinctive-back-alley-scoria-bricks-spotlight/ |access-date=31 May 2024 |work=York Press |date=20 April 2024 |language=en}} At its peak the company was taking 30% of the slag from the South-Tees works.

The bricks were produced by pouring the slag cauldrons, coming on trains from the steel works, into moulds made with hinged bottoms and mounted on a revolving platform allowing the moulds to be filled separately. As the bricks solidified they were removed and placed in a beehive oven, where the residual heat annealed the whole of the brick.{{cite news |title=English Slag Paving Blocks |url=https://www.newspapers.com/article/the-peabody-gazette-herald-english-slag/148394640/ |access-date=31 May 2024 |work=The Peabody Gazette-Herald |date=24 November 1910 |pages=7}}{{cite news |title=Scoriæ Bricks |url=https://www.newspapers.com/article/waterville-telegraph-scori-bricks/148423826/ |access-date=31 May 2024 |work=Waterville Telegraph |date=9 October 1874 |pages=1}} The bricks were found to be extremely durable against water, frost, chemicals and heavy loads, which led to them being used as a road surface. On the other hand, an early trial of the bricks in Liverpool found the bricks to wear unevenly and become slippery in wet conditions.{{cite book |last1=Boulnois |first1=Henry Percy |title=The Municipal and Sanitary Engineer's Handbook |date=1898 |publisher=E. & F.N. Spon |page=59 |url=https://books.google.com/books?id=lkVDAAAAIAAJ |access-date=31 May 2024 |language=en}}