The claw-purlin truss in the mansard roof has a purlin beam supporting the rafters of the lower and upper parts of the roof.
Roofs with a mansard structure are two-story roofs. The lower part of the structure has roof slopes with a steep inclination angle, and higher roof slopes with a smaller slope angle. Such a solution gives exceptionally wide possibilities of arranging the attic for utility purposes.
The mansard roof can be solved in both the collar and the purlin structure.
The construction of a claw-purlin roof is based on a common purlin beam of lower rafters with a large angle of inclination and upper rafters with a small angle. The lower pair of rafters is additionally braced with forceps.
For larger roof spans, when there is a possibility of additional use as a usable space of the upper part of the attic, a collar beam structure can be used, in which the collar flaps act as ceiling beams under the mezzanine.