Liquid Water Permeability of Exterior Wood Coatings–Testing According to a Proposed European Standard Method

By Jan Ekstedt, Gunilla Östberg

The proposed European standard method for the assessment of liquid water permeability, prEN 927–5, gives significant differences in water absorption values for different types of paints on wood. The proposed limits in the performance standard for the water absorption values for coatings to be used in different types of construction seem to be at acceptable levels.

There is a good correlation between the level of water absorption and outdoor experience of the performance of the paints. Aging can drastically influence the water protection properties of the coating. Some sort of aging of the samples is needed in the assessment of the water absorption properties of coatings. An artificial aging procedure is proposed in this paper.