Durability of some alternatives to preservative-treated wood. Progress report 2: Results from field tests after 5 years’exposure

IRG/WP 07-30442

M-L Edlund, J Jermer

A number of alternatives to preservative-treated wood have been tested according to EN 252 (stake test) and a specially designed ground-proximity field test, the latter in Sweden as well as in Hawaii, USA. Seven untreated wood species and four alternative wood treatments labelled as environmentally friendly (acetylation, linseed oil, heat treatment, vinyl polymer) were included in the study. Four copper-based wood preservatives and CCA were used as references and untreated pine (Pinus sylvestris) sapwood as control. Results after five years’ exposure showed that • Preservative-treated wood, with some exceptions, in general had far better performance than any of the untreated wood species and alternatives tested. • Amongst the alternatives, acetylated wood had a performance comparable to preservative-treated wood. • Heat-treated wood performed well above ground but poorly in ground and should therefore not be used in direct contact with the ground. • Linseed oil-treated wood with a high retention of linseed oil performed well, but because of poor appearance it seems difficult to use successfully in practice. • Larch heartwood performed better than any other untreated wood species tested – slightly better than both oak heartwood and pine (Pinus sylvestris) heartwood. • The ground-proximity test method was considered to be of doubtful value for an easy evaluation of the performance of wood above ground.


Keywords: durability, natural durability, acetylation, heat-treatment, linseed oil, decay, above-ground testing

Conference: 07-10-29/11-02 Taipei, Taiwan


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