Levels of Drywall Finishing
This trade document spells out accepted levels of finishing in a range of situations.
If you’re a professional, it’s important to be as specific as possible when drawing up acontractdrywalling工作。我看过合同the finished taping job is referred to in such vague terms as “taped to industry standards” or “taped to a workmanlike finish.”
This type of language can lead to problems. I know a taper who never received his final payment, because the owner wasn’t satisfied with the finished taping job. It seems the owner did his final inspection with the help of a 500-watt halogen light, and he found a lot of little problems that he wanted fixed (never mind that the surface would never be exposed to that type of lighting again).
In an effort to prevent these types of misunderstandings, four major trade associations developedRecommended Levels of Gypsum Board Finish, a document that does a great job of explaining the levels of finishing and where specific finishes are best suited. (The relevant sections of this document are reproduced below.)
To summarize,there are a number of factors to consider before you begin a taping job. These include the following:
- The degree of decorative treatment desired.
- The type and angle of surface lighting.
- The choice of paint and the method of application.
- The finish of the wall-covering material.
Factors that require a high level of finishing include the following:
- Critical lighting conditions.
- Any paint with a glossy (or even eggshell) sheen as a final finish.
- Thin wall coverings as a final finish.
Factors that require a lower level of finishing include the following:
- Textured surface as a final finish.
- Heavy-grade wall coverings as a final finish.
Recommended Levels of Gypsum Board Finish
This document (GA-214-96) was developed by the Association of the Wall and Ceiling Industry, Ceilings & Interior Systems Construction Association, Gypsum Association, and Painting and Decorating Contractors of America.
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 set in joint compound. Surface shall be free of excess joint compound. Tool marks and ridges are acceptable.
Frequently specified in plenum areas above ceilings, in attics, in areas where the assembly would generally be concealed, in a building’s service corridors, and in other areas not normally open to public view. Accessories are optional at specifier discretion in corridors and other areas with pedestrian traffic.
Some degree of sound and smoke control is provided: In some geographic areas this level is referred to asfire taping. Where fire-resistance rating is required for the gypsum board assembly, details of construction shall be in accordance with reports of fire tests of assemblies that have met the fire-rating requirement. Tape and fastener heads need not be covered with joint compound.
Level 2
All joints and interior angles shall have tape embedded in joint compound and wiped with a joint knife with a thin coating of joint compound left over all joints and interior angles. Fastener heads and accessories shall be covered with a coat of joint compound. Surface shall be free of excess joint compound. Tool marks and ridges are acceptable. Joint compound applied over the body of the tape at the time of tape embodiment shall be considered a separate coat of joint compound and shall satisfy the conditions of this level.
指定在防水gypsum backing board (ASTM C 630) 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 have tape embedded in joint compound and one additional coat of joint compound applied over all joints and interior angles. Fastener heads and accessories shall be covered with two separate coats of joint compound. 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 drywall primer prior to the application of final finishes. See painting/wallcovering specification in this regard.
Typically specified in appearance areas that are to receive heavy- or medium-texture (spray- or hand-applied) finish before final painting, or where heavy-grade wallcoverings are to be applied as the final decoration. This level of finish is not recommended where smooth-painted surfaces of light to medium wallcoverings are specified.
Level 4
All joints and interior angles shall have tape embedded in joint compound and two separate coats of joint compound applied over all flat joints and one separate coat of joint compound applied over interior angles. Fastener heads and accessories shall be covered with three separate coats of joint compound. 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 drywall primer prior to the application of final finishes. See painting/wall covering specification in this regard.
This level should be specified where flat paints, light textures, or light to medium wallcoverings are to be applied.
In critical lighting areas, flat paints applied over light textures tend to reduce joint photographing. Gloss, semigloss, and enamel paints are not recommended for use over this level of finish.
The weight, texture, and sheen level of wallcoverings applied over this level of finish should be carefully evaluated. Joints and fasteners must be adequately concealed if the wallcovering material is lightweight, contains limited pattern, or has a gloss finish, or if any combination of these finishes is present. Unbacked vinyl wallcoverings are not recommended over this level of finish.
Level 5
All joints and interior angles shall have tape embedded in joint compound, two separate coats of joint compound applied over all flat joints, and one separate coat of joint compound applied over interior angles. Fastener heads and accessories shall be covered with three separate coats of joint compound. A thin skim coat of joint compound or 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 finish paint. See painting specification in this regard.
This level of finish is highly recommended where gloss, semigloss, enamel, or nontextured flat paints are specified or where severe lighting conditions occur. This highest quality finish is the most effective method of providing a uniform surface and minimizing the possibility of joint photographing and of fasteners showing through the final decoration.
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谢谢你注意到石膏Association's levels of finish document. GA-214, has been revised many times since 1996 and is now entitled "Levels of Finish for Gypsum Panel Products." The most recent revision was completed in 2021. Also, a supplementary quick reference guide has been made available in recent years.
Both documents are available for free in the GA bookstore. More than 30 complimentary GA documents can be accessed, here:https://gypsum.org/ga-publications-at-a-glance/.