This article is about an architectural structure. For the large tree root, seeButtress root. For the Royal Canadian Air Force station, seeButtress, Saskatchewan.
Abuttress is anarchitectural structure built against or projecting from awall which serves to support or reinforce the wall.[1] Buttresses are fairly common on more ancient (typicallyGothic) buildings, as a means of providing support to act against the lateral (sideways)forces arising out of inadequately bracedroof structures.
The termcounterfort can be synonymous with buttress[2] and is often used when referring to dams, retaining walls and other structures holding back earth.
Early examples of buttresses are found on theEanna Temple (ancientUruk), dating to as early as the 4th millennium BC.[citation needed]
In addition toflying 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') buttressbisects the angle between the walls where they meet.[3][4]
The gallery below shows top-down views of various types of buttress (dark grey) supporting the corner wall of a structure (light grey).