Specifications

To ensure that the structure of any construction performs to the expected dead and live loads to which the building will be subjected over the course of its life, it is necessary to choose the size, length and grade of timber according to the expected loads and overall function. To determine the spanning ability of load carrying members, span tables allow users to choose an appropriate size and stress grade to achieve spanning needs.

The specification process is the process of the designer communicating their intentions to the supplier of the material. The properties required are generally determined by the performance requirements of the elements within the specific type of application.

Structural grading is the process by which timber is sorted into groups, or stress grades, with ideally, similar structural properties in each group.

Good risk management practices can help reduce the risk of damage from termite attack on buildings. The Termite Risk Management handbook details how, providing an invaluable resource for builders and designers across Australia.The handbook covers regulatory and statutory requirements, provides guidelines for use during the building process and finishes by discussing the risk of damage to houses from termites. Learn more here.

The basic premise of termite risk management is that the level of termite protection should match the level of site risk. Concepts such as “whole-of-house protection” and “integrated pest management” go some way towards meeting technical aspects of this debate.

The weathering process leads to a slow breaking down and wearing away of surface fibres, change in colour and roughening of the surface. Under extreme conditions, timber may deform, check, split and pull away from fasteners. The extent of weathering will vary with timber species and ambient conditions. Although unprotected timber has been used externally for centuries, the weathered effect is not always desirable. In most applications timber needs protection from the elements of water, cold, heat and ultra-violet light to promote a long service life. In addition to protection from the elements, finishes may provide a decorative effect.

The look and feel of an interior is determined by the combination of its functionality and the desired aesthetic. Where timber is used in the interior fit-out of a construction the finish applied to the timber often determines the strength of the aesthetic impact. A number of finishes are available to enable the designer and installer to enhance the beauty of the timber product and increase its functionality. Learn more about timber interior finishes here.

Maintenance affects all who use timber in buildings. Designers, architects, engineers and drafting staff need to ensure that the elements specified can be maintained effectively and inexpensively. They need to give some thought as to how it can be maintained. Builders need to use details that minimise contact between moisture and the wood, and are easy to inspect and repaint. Building owners, servicemen and maintenance trades need to take care of barriers and regularly inspect and touch-up timber elements and their protection.

A range of different chemical treatments has been developed to enhance the durability and service life of timber. These treatments impregnate the wood cells, making them resistant to decay, insects, weather or fire. While such treatments will add to the cost of the timber, they can significantly increase the timber's service life. When used in environments in which there are known biological hazards, it is cost-effective to specify treated timber and expect a longer service life or a lower cost maintenance schedule.