Effects of Capping on Long-Term Performance of Creosoted Douglas-Fir Piling in Newport Oregon

摘要

The American Wood Protection Association Standards require that any cuts or holes drilled into treated wood be supplementally treated with a preservative and that timbers or poles receive a water-shedding cap. However, these recommendations are routinely ignored, resulting in early decay and failure. The effects of supplemental treatments and capping on incidence of decay fungi was examined over a 34-year period at a marina near Newport, Oregon. Pile tops received combinations of fumigant or water diffusible preservatives and different cap types. Capping alone resulted in a gradual decline in the incidence of decay fungi, while fumigants without caps produced a sharp decrease in the incidence of decay fungi. Combinations of capping and supplementaltreatments produced the most rapid and long-lasting effects. The results highlight the benefits of supplemental treatments and capping for limiting the incidence of decay fungi in cut-off piling and poles.