Inspections and surveys for biodeterioration

Using a resistograph decay detection drill

The structural integrity of the timbers in buildings e.g. trusses, purlins, joists, wall plates, beams, etc. can be assessed with the use of a resistograph decay detection drill to establish the extent of decay and type of repairs required.

The decay is not immediately apparent either because a surface layer of sound timber hides the decay within the beam or sometimes the decay is in the middle of the beam, with a thin veneer of sound timber on the outer face. This is dry rot, which is very sensitive to air movement and desiccation. It is trying to maintain the ideal environment to decay the timber away from sunlight and air movement leaving the surface veneer.

The extent of the decay along the beam is governed by the amount of moisture available to the dry rot. The dry rot is able to generate moisture when digesting the cellulose, which can maintain the decay in the absence of desiccating air movement. The decayed timber remaining is mainly Lignin.

Determine the age of dry rot for legal and insurance claims

A sound building mycological knowledge and expertise in timber pathology would enable someone to establish the extent of infestation and determine the age of the decay in legal and insurance claims.

This is based on the calculations of extent of infestation in the masonry and extent of decay in timbers.

Figure 2: Non-destructive inspection of the floor void with the endoscope