Abstract: A naturally derived additive to fibrous materials and to building materials for imparting resistance to mold and mildew growth, including one or more additives extracted from a group of plant species, such as those from the families of Myrtacea, Rutaceaea, Zingiberaceae and Labiatae and essential oils derived from specific species such those selected from the following groups: Melaleuca quinquenervia, Melaleuca ericifolia, Melaleuca altemifolia, Melaleuca leucadendron, Citrus reticulata and Origanum vulgare.

Abstract: A gypsum board panel having two facing main surfaces and machine edge surfaces, the board including an outer gypsum layer in which a polymer additive has been entrained, and the machine edges being shaped to have a three-dimensional feature, such that the features are complementary, and one machine edge surface can engage the complementary surface of the machine edge of an adjacent gypsum board panel. The three-dimensional features may include a triangular, in cross-section, ridge, or a rectangular ledge, or a concave edge, with a corresponding complementary groove or depression on the opposed edge for engagement with the edge of an adjacent board.

Abstract: A method of manufacture of multilayer gypsum board, and a gypsum additive delivery system, including wet gypsum board passing through a board forming station in which additives are delivered to one or more layers of a multi layered gypsum board panels, such as engineered polymers, providing a better and more water resistance surface. Preferably, the gypsum board has a first layer of a mixture of set gypsum having an outer surface and a polymeric compound or wax emulsion additive entrained therein and impregnated in a thin sheet of randomly aligned inorganic fibers to essentially encase the core gypsum within two facing layers.