Treatment of constructional timber: for safe load-bearing structures
The combination of building design and the use of the right impra®lit wood preservative is the ideal means of providing safe, long term protection for timber constructions that frequently perform load-bearing functions. Wood-rotting fungi and insects are effectively prevented and building owners are saved from nasty surprises.
The process
The non-pressure process is ideal for the preventative impregnation of impra®lit preservatives for wood used as structural timbers for lath work or boarding in roofs.
The preservative penetrates into the wood through capillary action and diffusion, due to the hydrostatic pressure of the impregnation solution in the impregnation vessel or due to temperature differences in the impregnation fluids.
1) Dipping process
In the dipping process the wood is completely immersed into a bath filled with the impregnation solution. The preservative absorption depends on the dipping time and the solution concentration. In addition the impregnation result is influenced by the type of wood and the wood moisture content.
The wood moisture content at the start of the impregnation is at the fibre saturation point for water-soluble wood preservatives and for solvent-based preservatives it is less than 20 %.
2) Steeping
Special dipping process in which the immersed item remains for one or more days in the preservative solution. The long immersion period allows impregnation of even semi-dried timbers with a wood moisture content of between 3 and 50 %.
