This was achieved by the use of multiple decorated orders on the west face only, so that the chancel arch almost operated like a picture frame and in one direction only. The clergy had a different view – of an arch that was almost or entirely plain. For the laity the chancel arch was, especially in the twelfth and early-thirteenth centuries, an elaborate frame for the sacred ritual. What is striking about the structure of the chancel arch, however, is that there is a clear tendency for its two faces – the western public face and the eastern clergy face – to be very different. Roods and screens are very much secondary elements in church building added after the architecture and its sculpture defined its spaces, and arguably always seen as subject to change. The bricks used in such an arch are often referred to as 'voussoirs'.At St James, Hanslope grooves have been hacked out of the Romanesque capitals and impost blocks to house a later screen. This is also found sometimes in Romanesque architecture.ĭuring the 18th and 19th centuries, British bricklayers became aware that, by thickening the vertical mortar joint between regularly shaped bricks from bottom to top, they could construct an elliptical arch of useful strength over either a standard 'former', or over specially constructed timber falsework (temporary structure to be removed once the construction is complete). In Visigothic and Moorish architectural traditions, the voussoirs are often in alternating colours ( ablaq), usually red and white. The outer boundary of a voussoir is an extrados. Voussoir arches distribute weight efficiently, and take maximum advantage of the compressive strength of stone, as in an arch bridge. Each wedge-shaped voussoir turns aside the thrust of the mass above, transferring it from stone to stone to the springer's bottom face ( impost), which is horizontal and passes the thrust on to the supports. The word is a stonemason's term borrowed in Middle English from French verbs connoting a 'turn' ( OED). An enlarged and sometimes slightly dropped keystone is often found in Mannerist arches of the 16th century, beginning with the works of Giulio Romano, who also began the fashion for using voussoirs above rectangular openings, rather than a lintel (Palazzo Stati Maccarani, Rome, circa 1522). The keystone is often decorated or enlarged. The springer is the lowest voussoir on each side, located where the curve of the arch springs from the vertical support or abutment of the wall or pier. The keystone is the centre stone or masonry unit at the apex of an arch. Īlthough each unit in an arch or vault is a voussoir, two units are of distinct functional importance: the keystone and the springer. William Henry Playfair, University of Edinburgh: bevelled edges of each stone block emphasise the voussoirs, which have a curved base and together form a semi-circle at the top of each arch.Ī voussoir ( / v u ˈ s w ɑːr/) is a wedge-shaped element, typically a stone, which is used in building an arch or vault.

For the bridge design, see extradosed bridge.

Medieval architecture voussoir stone