Environmental stabilising

In the prevention of any form of biodeterioration, the 3 factors that must be taken into account are the material, the environment and the organism. The removal or alteration of any one of these can prevent the growth of decay organisms.

The control of the environment of a susceptible material, i.e. the control of physical conditions, rather than the application of biocides, is the oldest and still the most widely used method of preventing biological deterioration. For example, in the use of timber in construction the object has been to prevent its moisture content rising to levels at which wood rotting fungi can thrive.

The basic principle in the control of fungal growth is to render the micro-environment in or around the material in buildings as hostile as possible to the settlement, germination and spread of micro-organisms. This can be achieved by:

• preventing or limiting biological agents' growth and proliferation by means of toxic chemicals; or
• ensuring that the material to be protected is kept, or keeps itself, in such a physical condition that growth of biological agents is severely limited or prevented entirely.