This document has been excerpted from a consensus document
prepared by the Association of the Wall and Ceiling Industries International, Ceilings
& Interior Systems Construction Association, Gypsum Association, and Painting
and Decorating Contractors of America as a guide to gypsum board finishing.
The members of these international trade organizations are dedicated to providing
the best possible job for the most reasonable cost.
By incorporating the appropriate sections of this recommended specification into
the project documents, the architect, general contractor, and building owner can
better anticipate the final appearance of the decorated wall and ceiling system.
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The following levels of finish are established as
a guide for specific final decoration. The minimum requirements for each level shall
be as described herein.
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| 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.
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| 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 or in building
service corridors, and other areas not normally open to public view. Accessories
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 as ãfire taping.ä
Where a 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.
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| Level 2 |
All joints and interior angles shall have tape embedded
in joint compound and wiped with a joint knife leaving a thin coating of joint compound
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 embedment shall be considered a separate coat of joint compound
and shall satisfy the conditions of this level.
- Specified where water-resistant 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.
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| 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 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/ wall covering specification
in this regard.)
- 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.
This level of finish is not recommended where smooth painted surfaces or light to
medium wall coverings are specified.
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| 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 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 finishes is present.
Unbacked vinyl wall coverings are not recommended over this level of finish.
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| Level 5 |
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.
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
fee 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. Se painting
specification in this regard.
- This level of finish is highly recommended where
gloss, semi-gloss, enamel, or nontextured flat paints are specified or where severe
lighting conditions occur.
The 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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Provided courtesy of:
Hard Drywall, Inc. -- 578 Martin
Avenue-- Rohnert Park, CA 94928
(707) 686-2400 |
