Painted wood is a three-component system consisting of paint, wood, and the paint/wood interface. The critical component for maintaining long-term paint performance is the interface. (FOREST PRODUCTS JOURNAL Vol. 37, No. 11/12)
In many instances we are called in to a residential or a strata unit where the original coating and subsequent coats are peeling from the wood interface. This could be the result of moisture and the absence of a primer during original construction. In most cases this problem can be remedied by first removing the failed coatings by means of scraping, hand tooling, sanding or utilizing a chemical stripper and secondly priming with a penetrating oil primer prior to applying the top coat.
However, there are some instances where upon further review of the paint chips removed from the substrate we observed that wood fibers were attached to the paint chip.
Through our experience, we have concluded that in such occurrences the paint/wood interface on the siding has become critically compromised. Furthermore, the tension imparted on the existing coating when applying new coatings will create a surface tension that causes lifting of the original coatings.
Paint coatings applied in the past, though adhered adequately during the initial paint application, will, over time, continue to let go. As result unless the problem at the substrate interface is resolved as a contractor we are unable to warrant the bond of previous coats of paint to the substrate. In our opinion the best way to resolve the failure at the substrate interface level is full replacement of wood siding in all areas where extreme delamination of paint has occurred.