This highly versatile material creates bold and daring designs
For some, concrete is a refreshing antidote to an increasingly component-driven construction industry in which buildings are assembled rather than crafted on site. Poured and moulded in situ, concrete is rooted in place and time.
The material can be prefabricated, with precast concrete blocks often used for formwork, but to really bond with this amorphous, gloopy stuff , you need to bake it like a cake on site.
Concrete, a combination of cement, sand and stone, is a highly versatile material which can be made into pretty much any shape, a great way of achieving adventurous and complex, monolithic forms. That said, concrete doesn’t need to stay monolithic - it's easy to manipulate its smooth grey surface by adding stones, pigments, glass chips and tints, amongst other substances, to the concrete mix. Handcrafted concrete is poured into specially devised shutters which can be oiled and lined with different things such as smooth plywood or coarse, sawn timber, to leave different impressions on the material’s surface. Concrete also takes paint well.
Although it only makes up around 10 per cent of concrete, cement’s CO2 emissions account for most of concrete’s environmental burden. But don’t worry, the UK cement industry contains shades of green and has been busy blending cement with materials that are by-products of other industries, such as blast furnace slag and fuel ash, to reduce concrete’s energy consumption. There is even a concrete on the market called hempcrete which contains hemp.
With around 90 per cent of a house’s energy going on heating, cooling and lighting, concrete’s high-thermal capacity means the material can significantly reduce the building’s energy consumption. Exposed concrete can reduce daytime temperatures by up to 5˚C and can reflect light far into a building’s interior, reducing the need for artificial lighting.
Words: Karen Glaser