Abstract: A process for storing sound and heat insulating fiber materials comprising reducing fiber-fiber friction in the product by drying and by applying a friction reducing agent, preferably a silicone oil, onto said fibers, optionally freezing the product, preferably to a temperature below the glass transition temperature of the adhesive in the product, enclosing the product in an air-tight and moisture-proof material, evacuating the package and reducing the porosity of the product by at most 1/3 by compressing, sealing the package and, after storing, opening the package and optionally working the product mechanically.