Matter and surface
Exposed concrete
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It is concrete left visible just as it comes out of the formwork, without plaster or paint.
What it solves
It joins structure and finish in a single piece with little maintenance. Its mass dampens heat if it is given shade and ventilation.
Today
Design the formwork, joints and ties as part of the finish. Give the steel enough cover and protect faces exposed to water with eaves and drip edges.
Common mistake
Leaving concrete exposed without a drip edge or slope, which in the tropics gets stained with mold and runoff.
Tomorrow
Cements with calcined clays or slag lower the footprint without changing the appearance. In shade and breeze its mass keeps the coolness, but exposed to the afternoon sun it can overheat an entire plaza.
Fact Cement manufacturing generates about 8% of global CO2 emissions.
Where it comes from
- 1Rome Italy, since around 150 BC
Concrete with volcanic ash (pozzolana) raised the dome of the Pantheon, the largest unreinforced concrete dome. - 2Modern Movement Marseille, France, 1952
Le Corbusier called the surface bearing the imprint of the formwork at the Unité d’Habitation raw concrete (béton brut). - 3Argentine modern architecture Buenos Aires, Argentina, 20th century
Clorindo Testa designed the National Library in exposed concrete.
Masters
- Tadao Ando Church of the Light, Ibaraki, Japan, 1989
He left the concrete smooth and unfinished, with formwork joints aligned with the cross of light that cuts through the wall. He teaches that well-designed formwork is already the finish. - Paulo Mendes da Rocha Brazilian Museum of Sculpture, São Paulo, Brazil, 1995
He stretched a large 60-meter concrete beam over a Burle Marx garden that gives shade and marks the place. He uses exposed concrete as structure and as landscape at the same time.
See also
Also in Matter and surface
Diagrams and texts by LDB Arquitectura. They are shared under the CC BY 4.0 license, which allows them to be used and adapted with credit to the source.