Since the 1880s, millions of us have tramped over glass bricks, or blocks, set into cast-iron or concrete frames on the building side of pavements. Few of us will have given these hard working bricks much thought, and yet, like a kind of Cinderella of the building world, these underfoot servants have found fame and glamour in the designs of some of the most cherished modern buildings of the past 80 years.
Originally used in industrial buildings, but mostly as pavement lights to bring daylight into cellars and underground passageways, the glass brick was adopted by art deco architects for use in walls, screens and stairs, and, made very special indeed in such early modern movement masterpieces as the Maison de Verre (1928), a glass house constructed in an 18th-century Parisian courtyard, off rue Saint Guillame, by Pierre Chareau (1883-1950).
Chareau was not an architect, but a furniture and set designer who began his career, aged 16, with the Paris branch of the London department store, Waring & Gillow. And yet, his influence on architects ever since the completion of the Maison de Verre has been enormous. Glass bricks, as Chareau proved, bring a magical quality of light into buildings - bright yet diffused, effective yet softly glowing. From Chareau's time, walls of glass bricks were constructed, often curved and bringing a light-filled, streamlined glamour into the most humdrum buildings.
Ever since, glass bricks - as an architectural statement - have gone in and out of fashion and yet, whether fashionable or not, they have been used in ever increasing numbers in the design of airports, hospitals, railway stations, factories and public lavatories.
The bricks themselves are not strong enough to be built up into load-bearing walls, and so are either used as screen walls or set into other materials for support, typically iron and concrete. They are made from sand set into moulds and heated to 1,982C, about twice the temperature needed to make typical building bricks.
Hot stuff, then, and guaranteed to bring a little art deco, Hollywood or modern movement glamour into any building, however humble, and yet perfectly happy to be trodden on underfoot.
