Prevention of fungal attacks

In order to prevent the attacks of fungi it is essential that all timber should be properly dried before it is used. Once it has been installed the next step is to ensure that there is adequate ventilation, particularly of roof spaces and of the space below the floor boards on the ground floor. Ventilation louvres should be installed and these should not be closed in winter.

Damp may also arise from leaking drains and gutters, and from condensation arising on the inside of external walls.

If such constructional measures are not sufficient to prevent fungal growth it may be necessary to resort to chemical treatment, using one of the numerous substances which render the timber unsuitable as a substrate for fungi.

The surface of the timber can be painted or sprayed with the chemical, or the wood can be immersed in it, if this is still possible.

However, this will only protect the surface as the penetration of the chemical will be very limited, depending upon the type of timber, the nature of its surface and the degree to which it has been dried. The most efficient method of protecting timber is to impregnate it with the chemical, preferably under pressure, so that this reaches all parts. The heartwood of some trees cannot be impregnated but generally speaking this is protected naturally, e.g. in oak and pine.

Once the source of the damp has been traced and suitable countermeasures have been taken, it would be advisable to identify the fungus involved. This will usually involve consultation with an expert, al- though in some cases an experienced building craftsman may be able to help.

When dry rot has been identified it is essential that all the infected timber is removed and burnt in order to prevent the dispersal of the spores. In the case of panelling and floor boards it is advisable to remove about half a metre of timber beyond the infected area.

Adjacent brickwork should be carefully cleaned and then scorched with a blowlamp. Newly installed timber must, of course, be completely dry and it should have been impregnated under pressure.

The measures recommended above would apply in cases of serious attacks by other fungi, and here again the advice of professional experts can be sought.