The influence of the type of coating on thermally modified wood and the resulting durability of the surface treatment on a facade

Abstract

Many architects choose wooden façades to clad modern buildings, and Thermowood® is a popular choice for such applications. This study focuses on methods to prolong the “fresh” appearance of Thermowood® façades, specifically Thermo-ash (Fraxinus excelsior L.), Thermo-spruce (Picea abies (L.) Karst.) and Thermo-pine (Pinus silvestris L.). The study involves exposing three groups to natural weathering: one reference untreated group, one group with a thin-layer alkyd coating, and another with a thick-layer acrylate coating. The results indicated that a thick-layer acrylate coating was the most suitable treatment for Thermowood® surfaces, as this coating retained a better appearance and demonstrated superior coating durability. Furthermore, cost-benefit analysis (CBA) suggested a thick-layer acrylate coating proved to be the most suitable and cost-effective choice, based on architects’ desires, to maintain a “fresh/original” appearance.