Topical Problems Regarding the Wood Impregnation with Salts

摘要

Topical problems regarding the impregnation of spruce wood with protection salts are described. The attention is drawn to the mechanical debarking technique which, if not properly applied, leads to important losses of impregnatable sapwood and consequently to early failures. Early failures can be avoided by additional treatments of the ground contact zone of the poles. Spruce poles may easily be impregnated in the sap fresh state. During drying, however, shrinkage cracks occur after the impregnation. Therefore the unprotected heart region becomes exposed and is easily invaded by decay fungi. In order to avoid such not impregnated cracks, impregnation tests with a modified vacuum pressure procedure have been carried out on dry spruce poles. The results obtained and the conclusions are notified. Furthermore, questions concerning the impregnation of construction timber and the possibilities for the improvement of the impregnation of spruce wood by mechanical pretreatment in order to get a better penetration of the preservatives are discussed.