The use of fungicidal/insecticidal products and solutions to timbers by means of a gel or possibly paste is well recognised. The technique is explained in HSE Guidance Notes ‘In-situ timber treatment using timber preservatives.
A special type of emulsion which can be applied in the form of a thick paste to the surface area of the timber where deep penetration is necessary, and/or where it is essential to maintain a concentration of a pesticide product in a specific location. They are generally normally applied by trowel, caulking gun or alternatively by brush and are both insecticidal and fungicidal in action.
Timberwise timber paste consists of a concentration of fungicide in an emulsion which is intended to deeply permeate the timber structure.
In a case where the timber is damp at the time of treatment the active components diffuse quickly into the timber to allow protection against both fungal decay and wood boring beetle – until such a point in time that the timber dries down to a moisture content that will not assist fungal development.
Having said that, where timbers are dry the product would certainly diffuse and thus offer protection in the event that timbers turn out to be temporarily wet (and therefore susceptible to fungal attack) at any given time in the future.
This technique has been utilised effectively on numerous projects in the past.
It should be noted that, when managing fungal decay, it is crucial that measures are implemented to remove all source(s) of moisture leading to decay, in combination with the chemical treatments, as part of the overall specification of repairs.