Hammer Beam Roof Truss

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.

Hammer beam roof truss.

The hammer beam timber truss elegantly distributes the roof load extending weight down through the first floor system by way of heavy posts. Modified hammer beam trusses can use a lower tie beam or steel rods to. 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. 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.

A hammer beam truss is a cathedral roof truss with an open center. This truss behaves much more like an actual truss with the ability to have a tension line along the hammer beam up into the web down the other side and or up into the king post. 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. Above these components is a rack of common rafters.

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

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. A timber frame truss roof with ridge beam purlins and common rafters is a stunning combination that creates visual interest and structural complexity.