Timber preservation

Abstract

Wood preservation can be interpreted broadly to cover protection from fire, chemical degradation, mechanical wear and weathering, as well as biological attack. Chemical agents include strong acids and alkalies when stored in wooden vats. Mechanical wear, for example the decking of trucks, and of spindles and bearings, often necessitates renewal of timber before decay commences. Physical barriers to weathering can be provided by a simple paint coat as in exterior woodwork or by the use of heavy oils in the treatment of railway ties/sleepers which reduces the movement of the wood as well as providing biological protection. For these non-biological hazards it has been the practice to choose specific timbers for the more exacting jobs. For example hard maple for heavy duty floors, teak for ships’ decking, lignum vitae for propeller bushings. To some degree these special woods are being replaced by wood-plastic composites which offer good dimensional stability, chemical and electrical resistance and much reduced wear. Fire is a separate issue and is discussed later.