Sparren

Sparren is a term used in architecture and carpentry to refer to the rafters of a pitched roof. A rafter is an inclined timber that extends from the wall plate at the eaves to the ridge or crown of the roof, forming the main skeletal framework that supports the roof deck, sheathing, and coverings. Rafters are installed at regular spacing and work in conjunction with horizontal members such as purlins and with vertical or diagonal braces as required by the design.

Sparren transfer roof loads—dead loads from the roof materials and live loads such as snow or wind—into the walls and, ultimately, the foundation. The design and size of sparren depend on span, pitch, wood species, and local building codes. In traditional timber-framed construction they are often paired with other structural elements, including tie beams to resist spreading forces.

Materials range from solid timber to engineered wood products; modern constructions may also use metal components or composite materials. Sparren joints vary from simple end-bearing connections to complex mortises, tenons, or metal brackets, and may incorporate birdsmouth cuts to seat securely on the wall plate.

In architectural drawings, sparren are usually annotated as inclined members with a defined spacing, length, and bearing points. The term is most common in German-language architectural and carpentry contexts, but similar concepts exist worldwide under language-specific terms for rafters.