In order for wallcovering to be properly installed, walls must be smooth, clean and free of mildew, grease and old adhesive. Remove old wallcovering completely then remove any remaining adhesive with a good quality adhesive remover. Rinse wall and allow to dry. It is recommended that installers use a hard, acrylic, pigmented, wall-protecting primer that is SPECIFICALLY made for WALLCOVERING INSTALLATION and WALL PROTECTION. Do not install a wallcovering unless a temperature above 12 degrees Celsius is maintained in both areas of installation and storage for three (3) days after the installation. If there are any questions concerning the surface to be covered, a test installation of at least three (3) strips applied three (3) days in advance of the main installation is recommended. NEW DRYWALL Measures should be taken to ensure a clean flat surface. All joints should be taped, filled, and given ample time to dry. Use a single coat of pigmented wallcovering primer/ sealer. PLASTER WALLS Unpainted walls must be at least 90 to 120 days old and then washed with an acidic solution (like vinegar) to neutralize any alkaline areas. After this procedure is complete and the plaster wall is dry, a wallpaper acrylic prime/ sealer should be applied. Plaster and masonry wall surfaces should not exceed 5.5% moisture as measured by a moisture meter. A moisture meter should be used to determine moisture content. PREVIOUSLY PAINTED WALLS Fill cracks, holes and other imperfections with a spackling compound. When dry, smooth any rough areas by sanding with a fine grit sandpaper. Enameled or glossed surfaces should be sanded with coarse sandpaper and then primed. Be sure to clean walls with a bleach or ammonia and water solution and then apply a prime/ sealer to the entire wall