Dry rot is a misleading name, as the timber has to be damp for it to occur with >28% moisture content. After germination, the fungus can survive in 20-22%, which is lower than other major wood-rotting fungi. Dry rot, despite its name, thrives in damp environments. It can significantly mar the beauty of timber as it breaks down the material through fungal activity.
The S. Lacrymans fungus requires an initial germination temperature of between 21 and 25°C. Its preferred pH level is in the acid-to-neutral range, with limited air movement and water.
Therefore, despite its destructive reputation, dry rot has a high degree of sensitivity to its environment.
At a late stage of the infection, large brown cuboid damage with thick strands would normally be visible.
The fruiting body emerges prominently when the outbreak faces stress from insufficient water or a scarcity of woody material. This highlights the critical relationship between environmental conditions and the outbreak’s health. It underscores the importance of adequate resources for its thriving. (It is the flower of the fungus.)
Dry rot will not live in masonry (without a wood source). The strands bring nutrients back to the main body to help balance its digestive system. They can pass through weak lime mortar or render. However, it cannot pass through solid stone or brickwork. This explains its widespread presence in historically significant properties, highlighting its value and appeal.
Is there a cure
During the inspection, we should pay special attention to the structural timber sections. Whenever possible, let’s conduct drill tests to evaluate any wood rot.
Rapidly remove the water responsible (in all cases). This is not as straightforward as it sounds, as there can be numerous reasons for the delay. This is the main justification for chemical treatments.
I always strive to avoid chemical treatments during specification; any treatments used should be carefully targeted for maximum effectiveness.
Nonchemical treatments
A non-chemical treatment option briefly involves building envelope repairs, structural repairs with steel or slow-grown durable timber (e.g., West Coast Douglas fir), and membranes. Let’s combine these with effective ventilation or moisture sinks! We’ll monitor everything with moisture sensors and a proactive building maintenance schedule to ensure optimal conditions.
In Denmark, an effective method known as heat treatment has been successfully employed. It increases the building’s temperature to a remarkable 50°C over a span of just 16 hours. This innovative approach ensures optimal conditions for maintaining building integrity. It also promotes a healthier environment.