Timerber Joinery is a post and beam wood construction technique which does not make use of metal fasteners. For connection, it relies upon the precision interlocking of members for load transfer.
Many historic structures in North America were built at a time when metal fasteners were not readily available. Instead, wood members were joined by shaping the adjoining wood members to interlock using mortise and tenon joinery as shown in Figure 5.18 similar to that which is still used in the making of strong inconspicuous joints for furniture. The mated joints were restrained by inserting wooden pegs into holes bored through the interlocked members.
Timber joinery is presently undergoing a resurgence in popularity. It is being used where the exhibition of the craftsmanship required to precisely shape and interlock large wood members is a desired building feature. Although used mainly for upscale residential construction, timber joinery is also being used for commercial construction in some instances.
Metal fasteners are efficient means of transferring loads. They permit the used of moderate sized members to carry and transfer loads because the installation of metal fasteners requires only minimal removal of wood fibre in the area of the fasteners. Timber joinery, on the contrary, requires the removal of significant wood fibre where joints occur. For this reason, the adequacy of timber joinery is usually governed by the connections. Increased member size in relation to what would be required for construction employing metal fasters is often required.
In addition, wood engineering codes do not provide specific load transfer information for timber joinery due to sensitivity to quality of workmanship and material quality. As a result, engineering design must be conservative.
The amount of skill and time required for measuring, fitting, cutting, and trial assembly is far greater for timber joinery than for other types of wood construction. Therefore it is not the most economical means of connecting the members of wood buildings. Timber joinery is not used where economy is the overriding concern. Instead, it is used to provide a unique structural appearance which portrays the natural beauty of wood without distraction.
Figure 5.18 Basic Joints for Timber Joinery Construction