COFFER CEILINGSA coffer (or coffering) in architecture, is a sunken panel in the shape of a square, rectangle, or octagon in a ceiling, soffit or vault. A series of these sunken panels were used as decoration for a ceiling or a vault, also called caissons ('boxes"), or lacunaria ("spaces, openings"), so that a coffered ceiling can be called a lacunar ceiling: the strength of the structure is in the framework of the coffers.some example of ancient time are given below-

Gilded coffering on a barrel vault Giuliano da Sangallo's flat caisson ceiling,

of the apsis in Nazaré, Portugal Basilica di Santa Maria Maggiore, Rome

Late 16th century coffered ceiling Coffering on the Arch of Septimius Severus, Rome

of Santa Maria in Aracoeli, Rome

Coffered ceiling with 39 painted 15th-century flat coffered ceiling, Duomo of Pisa

panels in Palazzo Vecchio, Florence,

Italy

Inside Pisa's Duomo Painted coffering in octagons

and squares at Fontainebleau

Neoclassical coffered dome of Council chamber ceiling, Halifax Town Hall, 1863

James Wyatt's Pantheon, London

Commerce Court, Toronto Coffered and glazed dome,

Halifax Town Hall, 1863

Waffle slab is a reinforced-concrete floor and roof construction employing a square grid of deep ribs with coffers in the interstices.

LOAD ANALYSIS IN A COFFERED CEILING