File:Diaphragm arch, South East Tower, Beaumaris Castle.JPG
Diaphragm arch, South East Tower, Beaumaris Castle
File:TournusTonnengewölbe.jpg
Diaphragm arches in Romanesque architecture (St Philibert, Tournus)
A diaphragm arch is a transverse wall-bearing arch forming a partial wall dividing a vault or a ceiling into compartments<ref>Technical Terms and the Understanding of English Medieval Architecture" E. C. Fernie, Architectural History Vol. 44, (2001), pp. 13-21 [1]</ref> while also bracing the walls.Template:Sfn
When used under a wooden roof (with solid spandrels) it has the advantage of providing a partial firebreak.<ref>Architecture in Britain: the Middle Ages, Volume 12, p. 210</ref> It was first used in Roman Syria, during the 2nd century AD.<ref>Arte medievale, 1987</ref> The diaphragm arch is present in Islamic, Carolingian, Ottonian and Romanesque architecture.Template:Sfn