K.E.
McNURNEY,inc.
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Drywall & Interior Plaster FAQ |
Levels of Gypsum Board Finish Scope The following industry specifications describe various levels of gypsum board finishes prior to the application of decoration. The recommended level of finish for gypsum board wall and ceiling surfaces varies depending on their location in the structure, type of paint to be applied, final decoration to be applied and can also be dependent upon the type and strength of illumination striking the surface. Each recommended level of finish is described with typical applications. Terminology Accessories: metal or plastic beads, trim or molding used to protect, conceal or decorate corners, edges or the abutments of the gypsum board construction. Back-Roll: Rolling a spray painted surface (while still wet) with a paint roller immediately following spray application. Critical or Severe Lighting: strong side lighting from windows or surface-mounted light fixtures. Wall and ceiling areas abutting window mullions or skylights, long hallways or atriums with large surface areas flooded with artificial and/or natural lighting are a few examples of critical lighting areas. Strong side lighting from windows or surface mounted light fixtures may reveal even minor surface imperfections. Light striking the surface obliquely, at a very slight angle, greatly exaggerates surface irregularities. If critical lighting cannot be avoided, the effects can be minimized by skim coating the gypsum board surfaces, or by decorating the surface with medium to heavy textures, or by the use of draperies and blinds which soften shadows. In general: gloss, semi gloss and enamel paint finishes highlight surface defects; textures hide minor imperfections. Joint Photographing or Telegraphing: the shadowing of the finished joint areas through the surface decoration. Paint: Any pigmented liquid, liquefiable, or mastic composition designed for application to a substrate as a thin layer which is converted to an opaque solid film after application. Used for protection, decoration or identification or to serve some functional purpose, such as filing or concealing surface irregularities. Primer / Sealer Drywall: a paint material formulated to fill the pores and equalize the suction difference between gypsum board surface paper and the compound used on finished joints, angles, fastener heads, accessories and over skim coatings. A good primer / sealer (note: I always recommend a good quality paint as the primer coat because the "PVA" drywall sealers lack enough solids) formulated with higher binder solids, applied undiluted, is typically specified for new gypsum board surfaces prior to the application of texture materials and gloss, semi gloss, and flat latex wall paints. An alkali and moisture resistant primer and a tinted enamel undercoat may be required under enamel paints. Always consult with the finish paint manufacturer for specific recommendations. Primer / Sealer Wall coverings: white, self-sizing water base, "universal" (all purpose) wall covering primers have recently been introduced into the marketplace for use on new gypsum surfaces. These products are claimed to make drywall strippable, bind poor latex paint, allow hanging over glossary surfaces and existing vinyl's, hide wall colors, and to be water washable. Properly Painted Surface: A surface that is uniform in appearance, color and sheen. It is one that is free of foreign material, lumps, skins, runs, sags, holidays, misses, strike-through, or insufficient coverage. It is a surface which is free of chips, splatters, spills, or over spray which was caused by the contractors work force. Compliance with the criteria of a "properly painted surface" should be determined when viewed without magnification at a distance of five feet or more, under normal lighting conditions and from a normal viewing position. (note: a surface uniform in appearance, color, and sheen may not be sufficiently achieved with a coat of primer or a single coat of topcoat.) Skim Coat: a thin coat of joint compound over the entire surface to fill imperfections in the joint work, smooth the paper texture, and provide a uniform surface for decorating. Spotting: to cover fastener heads (nails, screws, staples) with joint compound. Texture: a decorative treatment of gypsum board surfaces. Texturing: regular or irregular patterns typically produced by applying a mixture of joint compound and water, or proprietary texture materials including latex base texture paint, to a gypsum board surface previously coated with primer/sealer. Texture material is applied by brush, roller, spray, trowel or a combination of these tools, depending on the desired result. Textured wall surfaces are normally over painted with the desired finish; over painting of textured ceiling may not be deemed necessary where an adequate amount of material is applied to provide sufficient hiding properties. A primer / sealer may not be required with certain proprietary texture materials. Always consult with the manufacturer of the texture material for specific recommendations. Tool Marks and Ridges: a smooth surface may be achieved by lightly sanding or wiping the joint compound down with a dampened sponge. Great care should be exercised to ensure that the nap of the gypsum board facing paper is not raised during sanding operations. Topcoat: The finish coat(s) of a coating system, formulated for appearance and or environmental resistance. Wall covering: Any type of paper, vinyl, fabric, or specialty material that is pasted onto a wall or ceiling in a wide array of colors, patterns, textures, and performance characteristics, such as wash ability and abrasion resistance. Levels Of Gypsum Board Finish LEVEL 0: No taping, finishing or accessories required. This level of finish may be useful in temporary construction or whenever the final decoration has not been determined. LEVEL 1: All joints and interior angles shall have tape embedded in joint compound. Surface shall be free of excess joint compound. Tool marks and ridges are acceptable. This level of finish often referred to as "fire taping", is frequently specified in plenum areas above ceilings, in attics, in areas where the assembly would generally be concealed, or in building service corridors and other areas not normally open to public view. Accessories (cornerbead, base shoe other trims) optional at specifier discretion in corridors and other areas with pedestrian traffic. LEVEL 2: All joints and interior angles shall have tape embedded in joint compound and one separate coat of joint compound applied over all joints, angles, fastener heads and accessories. Surface shall be free of excess joint compound, tool marks and ridges are acceptable. This level of finish is specified where water resistant drywall is used as a substrate for tile; may be specified in garages, warehouse storage or other similar areas where surface appearance is not of primary concern. LEVEL 3: All joints and interior angles shall be tape embedded in joint compound and two coats of joint compound applied over all joints, angles, fastener heads and accessories. All joint compound shall be smooth and free of tool marks and ridges. Note: It is recommended that the prepared surface be coated with a primer/sealer prior to the application of final finishes. This level of finish is typically specified in appearance areas which are to receive heavy or medium texture (spray or hand applied) finishes before final painting, or where heavy-grade wall coverings are to be applied as the final decoration. LEVEL 4: All joints and interior angles shall be tape embedded in joint compound and three coats of joint compound applied over all joints, angles, fastener heads and accessories. All joint compound shall be smooth and free of tool marks and ridges. Note: It is recommended that the prepared surface be coated with a primer/sealer prior to the application of final finishes. This level of finish is typically specified where light textures or wall coverings are to be applied, or economy is of concern. LEVEL 5: All joints and interior angles shall be tape embedded in joint compound and three separate coats of joint compound applied over all joints, angles, fastener heads and accessories. A thin skim coat of joint compound, or a material manufactured especially for this purpose, shall be applied to the surface. The surface shall be smooth and free of tool marks and ridges. Note: It is recommended that the prepared surface be coated with a primer/sealer prior to the application of final finishes. This level of finish is recommended where gloss, semi gloss, enamel or nontextured flat paints are specified or where severe side lighting conditions occur. This highest quality finish is the most effective method to provide a uniform surface and minimize the possibility of joint photographing and of fasteners showing through the final decoration. (note: Application of primer/paint products over Level 4 and Level 5 smooth finish: Industry experience demonstrates an effective method for achieving a visually uniform surface for both the primer and topcoat is spray application immediately followed by back rolling or roller application using good roller techniques such as finishing in one direction and using roller types and naps recommended by the paint manufacturer.
Resources ASTM C-840 - Standard Specifications for Application and Finishing of Gypsum Board. American Society for Testing and Materials. GA-505 - Gypsum Board Terminology. Gypsum Association. GA-214-96 - Recommended Levels of Gypsum Board Finish. Gypsum Association. FSCT - Coatings Encyclopedia Dictionary. Federation of Societies for Coatings Technology. DWFC - Recommended Specification for Preparation of Gypsum Board Surfaces Prior to Texture Application. Drywall Finishing Council Inc. DWFC - Interior Job Condition Specifications For The Application of Drywall Joint Compounds, Drywall Textures, and Paint/Coatings. Drywall Finishing Council Inc.
All of the statements, opinions, specifications, and recommendations on levels of gypsum board finish contained on this website are for general information purposes only and are not intended to imply that these are the only materials, methods, procedures, or processes which are available or suitable. Always consult with your licensed building professional. By publishing this web site K.E. McNurney, Inc. makes no express or implied warranty or other representation as to the quality, characteristics, or suitability of the materials or techniques described herein, and specifically disclaims any implied warranties of merchantability or fitness for a particular purpose which may arise by operation of law or otherwise.
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