The article presents a research of water-vapour permeability of the spruce and fir specimens finished with five different exterior wood film-forming pigmented coating systems based on the Cup method. The samples have been weathered by an accelerated weathering device far over 500 hours. The results of the measurements of water-vapour permeability before and after ageing have shown a decrease in permeability of ali the samples tested. Some major differences in permeability between some types of coating systems have been found. The method, when used together with the water uptake measurement during accelerated weathering, enables qualitative correlations of the coating protection functions of different coating systems.
|