Ground and structure
Cantilever
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It is an element that projects from the structure and is supported at one end only.
What it solves
It allows eaves, balconies and floors that project with no columns underneath. It gives shade and protects the facade and the walkway below from the rain.
Today
A cantilever needs an anchored part inside to counterbalance it. Check long-term deflection and vibration, especially on balconies.
Common mistake
Lengthening a cantilever without checking its anchorage, so that over the years the tip sags and cracks.
Tomorrow
A wide cantilever in front of the school creates a dry, cool place where children wait and play on rainy days. With heavier downpours that shelter is worth as much as a classroom.
Where it comes from
- 1Timber-framed houses Europe, peak in the 16th century
The upper floors projected over the street to gain space. Rouen banned them in 1520 for lack of air, and London in 1667 after the Great Fire. - 2Traditional Turkish house and casbahs of the Maghreb Turkey and Algeria, medieval and Ottoman period
The cumba is a projecting bay of the Turkish house. In the Casbah of Algiers medieval examples of projecting floors survive. - 3Fallingwater Pennsylvania, United States, 1936 to 1939
Frank Lloyd Wright cantilevered its terraces over a waterfall. Over the years they sagged and at the beginning of this century they were reinforced with post-tensioned cables.
Masters
- Frank Lloyd Wright Fallingwater, Pennsylvania, United States, 1937
He launches concrete terraces over the waterfall, anchored to the stone core of the chimney. Its story also teaches that cantilever deflection must be anticipated, since they had to be reinforced decades later.
Appears in the routes
See also
Also in Ground and structure
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.