Buttress

Vicolo di Formia (1956)
Oil painting by Antonio Sicurezza of an alleyway with buttresses between buildings

A buttress is an architectural structure built against or projecting from a wall which serves to support or reinforce the wall.[1] 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,[2] and is often used when referring to dams, retaining walls and other structures holding back earth.

Early examples of buttresses are found on the Eanna Temple (ancient Uruk), dating to as early as the 4th millennium BCE.[citation needed]

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.[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).

Buttress ground plans
Angled buttress 
Clasping or clamped buttress 
Diagonal or 'french' buttress 
Setback buttress 
Other Languages
беларуская: Контрфорс
беларуская (тарашкевіца)‎: Кантрафорс
català: Contrafort
čeština: Opěrný systém
Deutsch: Strebewerk
eesti: Tugipiilar
español: Contrafuerte
Esperanto: Kontraŭforto
euskara: Hormabular
français: Contrefort
Gaeilge: Taca
galego: Contraforte
한국어: 버트레스
Հայերեն: Կոնտրֆորս
hrvatski: Kontrafor
italiano: Contrafforte
қазақша: Контрфорс
lietuvių: Kontraforsas
Nederlands: Steunbeer
日本語: 控え壁
occitan: Contrafòrt
português: Contraforte
română: Contrafort
русский: Контрфорс
Simple English: Buttress
slovenščina: Opornik
srpskohrvatski / српскохрватски: Kontrafor
svenska: Strävpelare
West-Vlams: Steunbeir
中文: 扶壁