Effect of Wood Surface Treatment on Fungal Decay and Termite Resistance

Abstract

Surface treatments, such as immersion, brushing, spraying, dipping, and steeping have been extensively used to treat wood for use in low hazard class areas or as an on-site remedial/supplemental treatment of in-service wooden structures to extend their service life. In the present study the wood was subjected to steeping with three preservative formulations, i.e., copper azole type C (CA-C), alkaline copper quat type C (ACQ-C), and tebuconazole-propiconazole combo (TP), and the effect of surface treatment on fungal decay and termite resistance was evaluated. The results showed that the depth of chemical penetration into the wood and the surface absorption primarily depends on the permeability of the wood species. The efficacy of decay and termite resistance was determined by surface retention per unit area of the surface-treated wood. The surface treatment with CA-C, ACQ-C, and TP significantly enhanced the decay and termite resistances of the wood. But for low-permeability wood species such as Picea asperata, a higher concentration of preservatives or periodic re-surface-treatment is necessary to maintain resistance to decay and to termites.