Buttress

This article is about an architectural structure. For the large tree root, see Buttress root. For slang, see buttocks.

A buttress is an architectural structure built against or projecting from a wall which serves to support or reinforce the wall. Buttresses are fairly common on more ancient buildings, as a means of providing support to act against the lateral (sideways) forces arising out of the roof structures that lack adequate bracing.

The term counterfort can be synonymous with Buttress, and is often used when referring to dams, retaining walls and other structures holding back earth.

Terminology

In addition to flying and ordinary buttresses, brick and masonry buttresses that support wall corners can be classified according to their ground plan. A clasping or clamped buttress has an L shaped ground plan surrounding the corner, an angled buttress has two buttresses meeting at the corner, a setback buttress is similar to an angled buttress but the buttresses are set back from the corner, and a diagonal (or 'french') buttress is at 45 degrees to the walls.

Buttress ground plans

Angled buttress   Clasping or clamped buttress   Diagonal or 'french' buttress   Setback buttress

See also

• Flying buttress , Retaining wall
• Cathedral architecture , Cathedral diagram

Gallery

A buttress (and mostly concealed, a flying buttress) supporting walls at the Palace of Westminster   Buttresses at Sint-Petrus-en-Pauluskerk; Ostend, Belgium   Buttress at The Saviour Chapel, Żejtun, Malta   Flying buttress at Lincoln Cathedral, England   Wall buttresses in the form of a blind arcade cavity wall at Canton Viaduct, United States   Thick buttresses characterize Earthquake Baroque architecture like Paoay Church, Philippines   Buttresses of the western side of the Mosque of Uqba in Kairouan, Tunisia