Modern construction depends a great deal on acoustic materials as sound containment or sound control either in residential or commercial application. These materials are either mineral in nature or more recently have included synthetics as an economical material. There are many forms of these products available but the one thing they have in common is porosity and cavities that capture sound. In new installations, these products usually do not require a coating. The acoustical plaster is tinted to the final color before application and the ceiling panels are factory finished. Practically all on site finishing is limited to the repaint market.
To repaint acoustical materials, the object is to retain the porosity and cavities (to keep the sound deadening properties) while applying a new, decorative coating. this is best accomplished with flat latex rather than a higher sheen product. Harder drying, low sheen to high gloss materials will reduce the efficiency of the sound reduction. The flat finishes will provide a more uniform appearance without amplifying the inherently inconsistent surfaces of acoustic materials.
Acoustic plaster is best finished with airless spray. Using highly pigmented flat latex paint. Normally, this material is reduced with water to prevent bridging and give easy flow into the acoustic cavities. The reduced material is thin and may even be applied with H.V.L.P. spray equipment. Two coats are usually required and should be applied in opposite ( crisscross ) directions to eliminate shielded or shadowed appearance.
Acoustical panels are rolled almost as easily as sprayed ( using a 1″ or 1 1/2″ nap synthetic roller ). Again, two coats are recommended, rolled in opposite directions. In most cases, washing the surface prior to application is not necessary or feasible due to the delicate nature of the plaster and porosity of the panels. If washing is desired, a TSP solution or laundry detergent is suggested. Any water stains should be sealed with pigmented white shellac ( available in aerosol containers ) or a high quality water based stain blocker prior to finish.
