In many respects, timber is an ideal building material but because of its anisotropic nature, joints have to be carefully considered. The strength of a connection is usually determined by the timber properties in the weaker direction (perpendicular to the grain) in compression, shear or tension.
Carpentry joints were first developed for use in medieval frames. However they are still used in restoration, reproduction work and modern buildings that use traditional forms.
Generally these structures originally used oak or chestnut, but for the pegs unseasoned ‘green’ timber was used.
Timber connections, such as carpentry joints, have limited tension and moment capacity. Therefore most connections are configured to transfer compression and shear forces only.
Carpentry joints mainly fall into three categories: mortice and tenon joints, lap joints and scarf joints.