LEVELS OF GYPSUM BOARD FINISH
LEVEL 1 - Tape set in joint compound. Tool marks and ridges acceptable. Surface is free of excess joint compound.
Suggested use: Frequently specified in areas above ceilings, in attics, in areas where the assembly would generally be concealed, or in areas not normally open to public view. Some degree of sound and smoke control is provided. In some geographic areas, this level is referred to as "fire-taping". Tape and fastener heads need not be covered with joint compound.
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LEVEL 2 - Tape embedded in joint compound and wiped with a joint knife, leaving a thin coat of compound over tape.
Surface shall be covered by one separate coat of joint compound. Surface shall be free of excess joint compound. Tool marks and ridges acceptable.
Joint compound applied over the body of the tape at the time of tape embedment shall be considered a separate coat of joint
compound and shall satisfy the conditions of this level.
Suggested use: Specified where water-resistant gypsum backing board is used as a substrate for tile.
May also be specified in garages, warehouse storage or other similar areas where surface appearance is not of primary concern.
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LEVEL 3 - Taped as in level #2, then covered with two separate coats of joint compound.
Joint compound shall be smooth and free of tool marks and ridges.
Note: It is recommended that the prepared surface be coated with a drywall primer prior to the application of final finishes.
Suggested use: Typically specified in appearance areas which are to receive heavy or medium texture finishes before final painting, or where heavy-grade wall coverings are to be applied as the final decoration. This level of finish is not recommended where smooth painted surfaces, or light to medium weight wall coverings are specified.
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LEVEL 4 - Taped as in level #2, then covered with three separate coats of joint compound.
Joint compound shall be smooth and free of tool marks and ridges.
Note: It is recommended that the prepared surface be coated with a drywall primer prior to the application of final finishes.
Suggested use: This level should be specified where flat paints, light textures or wall coverings are to be applied.
In critical lighting areas, flat paints applied over light textures tend to reduce joint photographing.
Gloss, semi-gloss and enamel paints are not recommended over this level of finish. The weight, texture and sheen level of wall coverings applied over this level of finish should be carefully evaluated. Joints and fasteners must be adequately concealed if the wall covering material is lightweight, contains limited pattern, has a gloss finish or any combination of these features is present. Un-backed vinyl wall-coverings are not recommended over this level of finish.
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LEVEL 5 - Taped as in level #4. Surface shall be covered by three separate coats of joint compound. A thin skim coat of joint compound, or a material manufactured especially for this purpose, shall be applied to the entire 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 drywall primer prior to the application of final finishes.
Suggested use: This level of finish is highly recommended where gloss, semi-gloss, enamel or non-textured flat paints are specified, or where severe 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.
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GLOSSARY
Critical Lighting - Strong sidelighting from windows or surface-mounted light fixtures. Wall and ceiling areas abutting windows 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 sidelighting 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, 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 finishes highlight surface defects; textures hide minor imperfections.
Drywall Primer - A paint material specifically 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, and accessories and over skim coatings.
Skim Coat - Either a thin coat of joint compound applied or a material manufactured especially for this purpose and applied in accordance with manufacturer's recommendations, over the entire surface. A skim coat is intended to conceal small imperfections in joints and on the surface of the gypsum board, smooth the texture of the paper, minimize differences in surface porosity, and create a more uniform surface to which the final decoration can be applied. There is no specific mil thickness that constitutes a proper skim coat. A skim coat will not approximate a plastered surface. Once the skim coat dries, the gypsum board paper may show through and the treated joints, filled voids, and spotted fastener heads will likely be visible.
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 drywall primer. Texture material is applied by brush, roller, spray, trowel, or a combination of these tools, depending on the desired result.