Untersuchungen über Prüfverfahren, Beurteilungskriterien und Anforderungen für Außenbeschichtung auf Holzwerkstoffen der Klasse 100 G. Tl.1-3.

When using wood-based materials as exterior layer it is necessary to coat this material with a weathertight coating. Examinations of test-methods, criteria and requirements have been carried out to identify the weathertightness of liquid or paste-like done coating system. To this end, test-methods for lacquers, particle boards and other building materials have been examined and, where necessary, modified. Four coating systems weathered on building material in natural climate and on pieces of particle boards in conditioned chambers have been tested. The examinations concerned e.g. the moisture behaviour of wood-based materials in building materials, of the particle boards in conditioned chambers and of the coating systems themselves; further on the water vapour permeability, impact resistance, flexibility and adhesive strength of the coating systems as well as the absorption of wood-based materials by the capillary water flow through the water-repellent layers of the coating system. The results of the examination served to derivate a proposal for the testing of the coatings with at least one water-repellent layer on polyurethane (PUR) base. This proposal contains requirements and criteria for the coatings, general statements as to the testing and pretreatment of samples from house facades, the climates which should be applied, the different test-methods and the practical use of these test-methods. (WKI)