Abstract: The present invention is directed to methods for the spray application of additive compositions containing additive materials in the manufacture of sheet material products, such as paper products, textile products, and flexible sheet products by using compressed fluids, such as carbon dioxide and ethane, as a spraying medium. Additive compositions with high viscosity and which are substantially free of water and/or volatile solvent can be applied to sheet materials. Water-borne additive compositions with reduced water content can also be applied to sheet materials. One preferred spray method uses a decompressive spray of the compressed fluid which produces a uniform spray pattern and a narrow droplet size distribution that can improve application efficiency and quality when additive compositions are applied during the spraying step to rapidly conveyed sheet materials.