Hammerbeam roof

Pevsner’s Architectural Glossary (second edition) was published by Yale University Press in 2018. It defines a hammerbeam roof (or hammer-beam roof) as a structure with: ‘horizontal brackets projecting at the wall-plate level like an interrupted tie beam; the inner ends carry hammerposts, which are vertical timbers that support a purlin (or horizontal longitudinal timber) and are braced to a collar-beam above.’

Primarily used as a type of roofing support, a hammerbeam roof permits the support structure to extend beyond the length of the original piece of timber. This method may be more time consuming to construct, but it can be less expensive since it does not require long pieces of timber.

However, a hammerbeam roof is not considered a true truss, since it uses a method that rests one support beam inward and on top of the other. In this sense, it is similar to a corbel.

Tie beams are typically put in place to support this method of construction. The short pieces of timber that project from the wall and serve to anchor the tie beams are sometimes referred to as hammer-beams.

Hammerbeam roofs are often highly decorated. This technique was widely used during the English Gothic architecture period.

[edit] Related articles on Designing Buildings Wiki

• Corbel.
• Edinburgh Castle.
• English Perpendicular architecture.
• Gothic architecture.
• Long span roof.
• Rafter.
• The use of timber in construction.
• Truss.
• Types of roof.