Hammer Beam Roof Truss

A hammer beam truss is a cathedral roof truss with an open center.

Hammer beam roof truss.

Above these components is a rack of common rafters. Hammer beam roof english medieval timber roof system used when a long span was needed. Modified hammer beam trusses can use a lower tie beam or steel rods to. A timber frame truss roof with ridge beam purlins and common rafters is a stunning combination that creates visual interest and structural complexity.

This truss is favored in heavy timber construction in situations where wide clear spans are required and where a different structural member would obstruct the view of gable end windows. For a truss of 32 feet span a 1 1 4 inch square bar will be ample and it may be twisted to give a more pleasing effect. These trusses can almost always be self contained not requiring any additional framing to be supported. This truss has the appearance of a hammer beam truss and when placed over a high nave the effect of the rods is not objectionable.

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. In a hammerbeam roof a series of short wooden horizontal beams curved support beams and wooden. 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. There is a hierarchy of timber framing at work here with trusses supporting the ridge and purlin beams.

The hammer beam timber truss elegantly distributes the roof load extending weight down through the first floor system by way of heavy posts. 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.