Hammer Beam Roof Structure

A false hammerbeam roof truss has two definitions.

Hammer beam roof structure.

Diagram of a hammerbeam roof hammerbeam roof systems developed in english architecture in the medieval period. Modified hammer beam trusses can use a lower tie beam or steel rods to. Herland s experience at winchester in the early 1390s. A hammer beam timber frame bent pictured above is a beautiful and more complicated design and creates dramatic vaulted spaces.

Hammer beam roof english medieval timber roof system used when a long span was needed. The structure a hammer beam roof is analysed from the perspective of the king s carpenter hugh herland. Not a true truss the construction is similar to corbeled masonry see corbel in that each set of beams steps upward and inward by resting on the ones below by means of curved braces and struts. Unless the structure has the ability to resist the outward thrust present at the bottom of the hb truss the modified hb truss is the way to go.

1 there is no hammer post on the hammer beam 16 17 as sometimes found in a type of arch brace truss 18 or. The hammer beam bent is often associated with religious structures great halls or great rooms. A hammerbeam is a form of timber roof truss allowing a hammerbeam roof to span greater than the length of any individual piece of timber in place of a normal tie beam spanning the entire width of the roof short beams the hammer beams are supported by curved braces from the wall and hammer posts or arch braces are built on top to support the rafters and typically a collar beam. A true hammer beam truss like the one shown here relies on exterior buttresses reminiscent of the flying buttresses of notre dame cathedral to hold it in place and keep the roof planes from spreading apart.

This analysis is based on drawings made in 1913 to facilitate the repair of the roof and on the author s archaeological reconstruction of the carpentry based on those drawings. The hammer beam is the short beam at the base that attaches to the wall. For any would be castle builder a great hall is probably on the wish list to be built as part of the structure and having a hammer beam type roof over the room is probably part of the design. Hammer beam trusses can have a single hammerbeam or multiple hammerbeams.

The hammer beam roof is the crowning achievement in english gothic architecture and open timber roof design. It uses reinforced posts curving slightly outward from the wall to support the weight. A hammer beam truss is a cathedral roof truss with an open center. We usually use the hammer beam itself as a robust bending member as the hammer post vertical and brace into the post go into significant compression.