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| Delamination of
texture on drywall surfaces is an expensive and apparently increasing problem. Job site
investigation of this problem reveals not one cause, but
several. Read more >>> |
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| Recommended Surface
Treatment For Finishing Gypsum Panels To Attain a Level 5 Finish |
| 1. Scope. The
purpose of this document is to describe guidelines for determining the visual performance expectations
that an acceptable surface treatment will impart to achieve a Level 5 finish over a properly prepared
Level 4 joint treated gypsum panel surface. |
| 2. Terminology. The
following definitions are applicable to this document. |
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gypsum panel products (n): The
general name for a family of sheet products consisting essentially of gypsum. - ASTM C11 |
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inspection lighting (adj): Inspection
lighting shall be representative of normal lighting conditions in intensity and location. |
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normal lighting conditions (adj): Normal
lighting conditions are described as those in place when the project is finished. This includes, but
not limited to, design lighting (e.g. wall washers, spots and floods, etc) and natural
lighting." - PDCA |
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normal viewing position (adj): The
normal viewing position shall be at any angle provided it is established at a minimum distance of five
feet perpendicular from the surface to be viewed. |
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properly painted surface (adj) : One
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 drips, splatter, spills, or overspray which were caused by the contractor's workforce.
Compliance to meeting the criteria of a "properly painted surface" shall be determined
when viewed without magnification at a distance of five feet or more, under normal lighting conditions
and from a normal viewing position. - PDCA |
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skim coat (n): A
type of surface treatment that employs the use of joint compound to minimize
surface variations. |
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surface treatment (adv): Any
method of treating a gypsum panel substrate to minimize surface variations. |
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uniform surface (n): A
gypsum panel substrate that exhibits the same visual appearance properties over the entire surface
area when decorated. |
| 3. Guidelines For Determining An Acceptable Surface Treatment. The
following performance descriptions have been established as a guide. |
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Index |
3.1 Conditions for Installation |
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3.2 Materials |
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3.3 Visual Performance Expectation |
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3.1 Surface Treatment - Conditions for Installation |
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3.1.1 Surface
treatment shall be installed over a properly prepared gypsum panel substrate. The level of gypsum
panel finish should meet the minimum criteria of a Level 4 finish as described in; GA-214 "Recommended
Levels of Gypsum Board Finish", NWCB "Recommended Levels For Finishing Of Gypsum Board",
and/or equivalent.
3.1.2 Surface treatment will be applied over unpainted properly prepared gypsum
panel substrates only.
3.1.3 - Leave sufficient material that minimizes surface variations over
joints, fasteners, trims, and gypsum panel surface in accordance to the jobsite standard.
3.1.4
During the construction phase, jobsite conditions should be maintained in accordance with Drywall Finishing
Council document titled, "Interior Job Condition Specification For The Application of Drywall Joint
Compounds, Drywall Textures, And Paint / Coatings".
3.1.5 A jobsite standard of the finishing
system, surface treatment, and decoration of gypsum panel substrate shall be constructed for the purpose
of establishing a level of visual appearance deemed acceptable.
3.1.6 The jobsite standard shall
be constructed in advance of work.
3.1.7 The constructed jobsite standard shall be representative
of the wall and ceiling configuration typically found at the jobsite. |
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3.2 Surface Treatment - Materials |
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3.2.1 All surface treatment
materials should be compatible with materials in the underlying properly prepared gypsum panel substrate,
and provide an acceptable surface to receive decoration.
3.2.2 Any material may be used that meets
the visual performance expectations of a surface treatment applied over a properly prepared gypsum panel
substrate.
3.2.3 Surface treatment materials may be applied by any method deemed practical and/or
recommended by the manufacturer. |
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3.3 Surface Treatment - Visual Performance Expectation |
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3.3.1 Provide a finished surface
that is suitable for decoration.
3.3.2 Provide a uniform decorated surface when viewed without
magnification under occupancy conditions with normal lighting conditions and from a normal viewing
position. Consideration shall be given to window treatment and/or any other decorative finishes that
could affect lighting and viewing.
3.3.3 Inspection lighting shall be representative of normal
lighting conditions in intensity and location.
3.3.4 Achieves a level of visual appearance as
established by the approved jobsite standard. |
| 4. Comments. The
following definitions are applicable to this document. |
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intent - This
performance description is designed to minimize decorating problems that can occur due to surface
variations between the gypsum panel surface and areas finished with joint compound. |
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surface smoothness - Because
the joints and fasteners must be concealed with fill and finish coats of joint compound, it is impossible
to achieve a finished surface that is a flat plane. Instead, the joints and fasteners are finished with
graduated arcs designed to prevent recesses or ridges that result in distinct shadows in critical light. |
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environmental control - Temperature,
humidity, and airflow should remain constant, and as close to occupancy conditions as possible. The
potential for finishing and decorating problems is minimal when job environmental conditions match
occupancy environmental conditions. Controlling and maintaining environmental conditions is key.
Changes in temperature, humidity, and airflow can have a profound adverse effect. |
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environmental limitations / considerations - All
products shall be applied and maintained in accordance with manufacturers recommendations. |
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environmental conditions - Follow
the Drywall Finishing Council document titled, "Interior Job Condition Specification For The
Application of Drywall Joint Compounds, Drywall Textures, And Paint / Coatings". |
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gypsum panel preparation - To
achieve optimum surface treatment performance over gypsum panel products, the substrate must meet
the minimum performance criteria of a Level 4 finish. Refer to Gypsum Association GA-214 titled,
"Recommended Levels of Gypsum Board Finish". |
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project standard specification - A
project standard of the approved wall and/or ceiling configurations shall be established to provide
a visual sample constructed, finished, and decorated in accordance with applicable project specifications.
As a guideline, refer to PDCA P5-94 titled, "Benchmark Sample Procedures For Paint and Other Coating
Systems". |
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level of paint finish - A
Level 5 paint finish is recommended. This system when combined with the Level 5 gypsum board finish
is the most effective method to minimize joint and fastener photographing and provides the most uniform
final finish. Refer to Drywall Finishing Council document titled, "Recommended Levels of Paint
Finish Over Gypsum Board". |
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installation - It
is not the intent of this document to direct, specify and/or limit installation of surface treatments
to a particular trade. |
| 5. Resources. The
following definitions are applicable to this document. |
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ASTM C-11. Standard
Terminology Relating to Gypsum and Related Building Materials and Systems. American Society for Testing
and Materials, West Conshohocken PA |
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DWFC. Interior
Job Condition Specifications For The Application of Drywall Joint Compounds, Drywall Textures, and
Paint / Coatings. Drywall Finishing Council Incorporated, Garden Grove CA |
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DWFC. Recommended
Levels of Paint Finish Over Gypsum Board. Drywall Finishing Council Incorporated, Garden Grove CA |
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DWFC. Recommended
Specification for Preparation of Gypsum Board Surfaces Prior To Texture Application. Drywall
Finishing Council Incorporated, Garden Grove CA |
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FSCT. Coatings
Encyclopedic Dictionary. Federation of Societies for Coatings Technology, Blue Bell PA |
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GA-214-96. Recommended
Levels of Gypsum Board Finish. Gypsum Association, Washington DC |
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GA-216-00. Application
and Finishing of Gypsum Board. Gypsum Association, Washington DC |
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PDCA, Glossary of Terms. Painting
and Decorating Contractors of America, Fairfax VA |
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PDCA. Standard P1-92. Touch-Up
Painting and Damage Repair - Financial Responsibility. Painting and Decorating Contractors
of America, Fairfax VA |
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PDCA. Standard P4-94. Responsibilities
for Inspection and Acceptance of Surface Prior to Painting and Decorating. Painting and Decorating
Contractors of America, Fairfax VA |
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PDCA, Standard P5-94. Benchmark
Sample Procedures for Paint and Other Coating Systems. Painting and Decorating Contractors of
America, Fairfax VA |
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