Assessing timber decay organisms

The following techniques are used to diagnose decay:

• physiochemical and morphological characteristics of decay;
• cultural characteristics of organisms;
• genetic fingerprinting;
• trained animals; and
• Volatile Organic Compounds (VOCs) testing.

Special search techniques

The condition of concealed timbers and cavities may be deduced from the general condition and moisture content of the adjacent structure. Only demolition or exposure work can enable the condition of timber to be determined with certainty and this destroys what it is intended to preserve.

A non-destructive approach is therefore required and, to help reduce uncertainty, instrumentation and test equipment can be useful at this stage. Tests and instruments are only aids to the surveyor: results must be interpreted with experience and care. A slavish reliance on any technique, and failure to take into account its limitations, is a recipe for disaster.

Non-destructive inspection may include the use of trained animals, fibre-optics, ultrasonic and infrared techniques.

Assessment of the activity of decay organisms involves the following:

• detection of decay organisms;
• identification of decay organisms;
• assessment of the viability of decay organisms;
• quantification of the state of decay;
• environmental conditions assessment; and
• structural assessment of decay.