What is a collar beam primarily used for in construction?

A collar beam is primarily used in construction to tie opposite rafters together. Its main function is to provide horizontal support in the roof structure, helping to maintain the shape of the roof and prevent the rafters from spreading apart under the weight of the roof or any additional loads, such as snow. By connecting the rafters, the collar beam contributes to the overall stability and integrity of the roof structure, particularly in pitched roofs, where the forces acting on the rafters can lead to potential failure if not adequately supported.

This important role distinguishes collar beams from other structural components, such as vertical support beams, which serve to help with load distribution but do not have the same function of tying together rafters. Similarly, the collar beam is not a decorative element or a type of framing for exterior walls, as its purpose is specifically functional in the context of roof construction.