collar beam

Quick Reference

Transverse horizontal straight, cambered, or cranked timber connecting pairs of cruck-blades or rafters in a position above their feet and below the apex of the roof, also called a collar-beam, span-beam, spar-piece, top-beam, or wind-beam, thus a collar-beam roof or collar-roof has collars used in its construction. A collar-or arch-brace is a structural timber to stiffen a roof-truss. An extended collar extends beyond its principal to a gable-wall in roofs with large gables, often with the lower part of the principal omitted. A collar-plate, collar-purlin, or crown-plate is a horizontal timber plate resting on collars to tie trusses together, set above a crown-post.

Subjects: Architecture.

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