Hammerbeam Roof

A hammerbeam roof is a decorative open timber roof in which short horizontal beams, called hammer beams, project inward from the tops of the walls. Each hammer beam is supported by a curved brace beneath it and carries a vertical post (hammer post) and further braces above. This arrangement replaces a full-width tie beam, so the roof can cover a wider space than the length of any available timber. It is often called the most spectacular achievement of the English medieval carpenter.

How it works

The weight of the roof passes down through the hammer posts and braces onto the hammer beams, then through the wall braces into the masonry. Because there is no continuous tie beam, the truss pushes outwards on the walls, so hammerbeam roofs usually need thick walls or buttresses.

Types include:

• Single hammerbeam: one tier of brackets.
• Double hammerbeam: a second tier above the first, used for taller roofs.
• False hammerbeam: the hammer beam has no post above it; the brace runs straight to the collar.

Early examples

Possibly the earliest standing hammerbeam building in England is the Pilgrims' Hall in Winchester Cathedral Close, built about 1310. Hammer beams also appear, hidden behind timber vaulting, in the octagon lantern of Ely Cathedral, begun in 1334 by carpenter William Hurley.

Westminster Hall

The best-known example is Hugh Herland's roof over Westminster Hall, London, commissioned by Richard II in 1393. It spans about 20.7 m (68 ft) and is decorated with 26 carved angels.

Later examples

Notable later hammerbeam or false hammerbeam roofs include the Great Halls of Hampton Court Palace and Eltham Palace, and many East Anglian parish churches with carved "angel roofs", such as St Mary's, Bury St Edmunds. At Stirling Castle, the Great Hall roof built around 1502 was reconstructed between 1991 and 1999 with 57 trusses of green oak.

Regions

The hammerbeam is essentially an English form. Continental European carpenters solved long spans more often with complex trussed or vaulted roofs hidden above masonry vaults.