Attachment_18_-_Section_09_23_00_Gypsum_Plastering.pdf

FA4419-14-R-0102

Attachment 18

SECTION 09 23 00

GYPSUM PLASTERING

PART 1 GENERAL

1.1 REFERENCES

1.2 SUBMITTALS

1.3 QUALITY ASSURANCE

1.3.1 Sample Panels

1.3.2 Sustainable Design Certification

1.4 DELIVERY, STORAGE, AND HANDLING

1.5 ENVIRONMENTAL CONDITIONS

1.5.1 Gypsum Plaster

1.6 Gypsum Plaster Full Size Sample

PART 2 PRODUCTS

2.1 MATERIALS

2.2 GYPSUM BASE COAT PLASTER

2.2.1 Gypsum Neat Plaster Base Coat

2.2.2 Gypsum Ready-Mixed Plaster Base Coat

2.2.3 Gypsum Wood-Fibered Plaster Base Coat

2.2.4 High Strength Gypsum Plaster Base Coat

2.3 GYPSUM FINISH COAT PLASTER

2.3.1 Gypsum Gaging Plaster Finish Coat

2.3.2 High Strength Gypsum Gaging Plaster Finish Coat

2.3.3 Gypsum Molding Plaster for Ornamental Plaster

2.3.4 Keene's Cement Finish Coat

2.3.5 Acoustical Plaster Finish Coat

2.4 HYDRATED LIME

2.5 AGGREGATES

2.5.1 Sand for Gypsum Base Coats

2.5.2 Sand for Gypsum Sand Float Finish

2.5.3 Lightweight Aggregates, Perlite or Vermiculite for Gypsum Base Coat

2.5.4 Silica Sand or Perlite Fines

2.6 WATER

2.7 PROPORTIONING

2.7.1 Gypsum Base Coat Plaster

2.7.1.1 Sand and Gypsum Plaster Base Coat

2.7.1.2 Lightweight Aggregate and Gypsum Plaster Base Coat

2.7.1.3 Sand and Wood Fibered Gypsum Plaster Base Coat

2.7.1.4 Sand and High-Strength Gypsum Plaster Base Coat

2.7.2 Gypsum Plaster Finish Coat

2.7.2.1 Lime-Putty

2.7.2.2 Lime-Putty Gypsum-Gaged (White Coat)

2.7.2.3 Aggregated Finish Coat

2.7.2.4 Gypsum Sand Float Finish[ for [_____]]:

2.7.2.5 Keene's Cement Lime-Putty Finish[ for [_____]]

2.7.2.6 High Strength Gypsum-Gaged Plaster Finish[ for [_____]]

2.7.2.7 Acoustical Plaster Finish[ for [_____]]

2.8 MIXING

2.8.1 Job-Mixed Materials

2.8.2 Ready-Mixed Packaged Materials

2.9 BONDING AGENT

PART 3 EXECUTION

3.1 SURFACE PREPARATION

3.2 WORKMANSHIP

3.2.1 Slump Tests

3.2.2 Application

3.2.3 Control And Expansion Joints

3.2.4 Curing

3.2.4.1 Gypsum Plaster

3.3 GYPSUM PLASTER WORK

3.3.1 Gypsum Plaster Thickness Requirements

3.3.2 Gypsum Plaster Basecoat Work

3.3.2.1 Gypsum Two-Coat System

3.3.2.2 Gypsum Three-Coat System

3.3.3 Gypsum Plaster Finish Coats

3.3.3.1 Lime-Putty and Gypsum-Gaged Finish Coats

3.3.3.2 Keene's Cement Lime-Putty Finish Coat

3.3.3.3 Gypsum Sand Float Finish Coat

3.3.3.4 Acoustical Plaster Finish Coat

3.4 ORNAMENTAL PLASTER WORK

3.5 PATCHING AND POINTING

-- End of Section Table of Contents –

SECTION 09 23 00

GYPSUM PLASTERING

PART 1 GENERAL

1.1 REFERENCES

The publications listed below form a part of this specification to the extent referenced. The publications are referred to within the text by the basic designation only.

ASTM INTERNATIONAL (ASTM)

ASTM C11 (2013) Standard Terminology Relating to Gypsum and

Related Building Materials and Systems

ASTM C206 (2003; R 2009) Standard Specification for Finishing Hydrated Lime

ASTM C28/C28M (2010) Gypsum Plasters

ASTM C35 (2001; R 2009) Inorganic Aggregates for Use in Gypsum Plaster

ASTM C472 (1999; R 2009) Physical Testing of Gypsum, Gypsum Plasters and

Gypsum Concrete

ASTM C59/C59M (2000; R 2011) Gypsum Casting Plaster and Gypsum Molding

Plaster

ASTM C61/C61M (2000; R 2011) Gypsum Keene's Cement

ASTM C631 (2009) Bonding Compounds for Interior Gypsum

Plastering

ASTM C842 (2005; E 2010; R 2010) Application of Interior Gypsum Plaster

ASTM E1042 (2002; E 2008; R 2008) Acoustically Absorptive Materials Applied by

Trowel or Spray

SCIENTIFIC CERTIFICATION SYSTEMS (SCS)

SCS Scientific Certification Systems (SCS) Indoor

Advantage

UL ENVIRONMENT (ULE)

ULE Greenguard UL Greenguard Certification Program

1.2 SUBMITTALS

Government approval is required for submittals with a "G" designation; submittals not having a

"G" designation are [for Contractor Quality Control approval.][for information only. When used, a designation following the "G" designation identifies the office that will review the submittal for the Government.] Submit the following in accordance with Section 01 33 00 SUBMITTAL

PROCEDURES:

SD-03 Product Data

Certification

SD-04 Samples

Gypsum Plaster[; G][; G, [_____]]

Submit four 900 mm 36 inch square panels of varying texture for the Contracting Officer's approval.

Full Size Sample[; G][; G, [_____]]

SD-08 Manufacturer's Instructions ready-mix gypsum plaster

[ Acoustical Plaster Finish]

Submit manufacturer's printed mixing instructions for ready-mix plaster[ and acoustical plaster finish].

1.3 QUALITY ASSURANCE

1.3.1 Sample Panels

Erect sample panel at the building site, or as otherwise directed. Finished gypsum plaster work must match the approved sample panel.

1.4 DELIVERY, STORAGE, AND HANDLING

Deliver manufactured materials in the manufacturers' original unbroken packages or containers which are labeled plainly with the manufacturers' names and brands. Keep cementitious materials dry and stored off the ground, under cover, and away from sweating walls and other damp surfaces until ready for use.

1.5 ENVIRONMENTAL CONDITIONS

1.5.1 Gypsum Plaster

Maintain an ambient temperature of not less than 55 degrees F continuously during plastering, and drying, and until occupancy heating conditions are established in the area.

Maintain this temperature for not less than one week prior to the application of plaster.

Provide regulated ventilation to prevent "sweatouts" or "dry-outs." When the building is exposed to hot dry winds or day-to-night temperature differentials of 20 degrees F or more, cover openings that are not glazed. Gypsum and related materials must conform to

ASTM C11.

1.6 Gypsum Plaster Full Size Sample

After selection of an acceptable texture, construct a sample panel separate from the building, minimum size of 4 ft in height, by 4 ft in length, using 6 inch metal studs, and gypsum board, metal lath and gypsum plaster. The sample wall must show all aspects of gypsum plaster work, including but not limited to, expansion joints, control joints, corner extrusions, and casing beads.

Finish work must match the approved sample panel. The Contractor shall protect the sample wall from damage during the length of the contract.

PART 2 PRODUCTS

2.1 MATERIALS

Conform to the specifications, standards, and requirements specified herein. Provide asbestos-free materials.

2.2 GYPSUM BASE COAT PLASTER

2.2.1 Gypsum Neat Plaster Base Coat ASTM C28/C28M.

2.2.2 Gypsum Ready-Mixed Plaster Base Coat ASTM C28/C28M.

2.2.3 Gypsum Wood-Fibered Plaster Base Coat ASTM C28/C28M.

2.2.4 High Strength Gypsum Plaster Base Coat ASTM C28/C28M, gypsum neat plaster, except plaster must have a compressive strength of not less than 2,500 psi, when tested dry in accordance with ASTM C472.

2.3 GYPSUM FINISH COAT PLASTER

2.3.1 Gypsum Gaging Plaster Finish Coat - ASTM C28/C28M.

2.3.2 High Strength Gypsum Gaging Plaster Finish Coat - ASTM C28/C28M, gypsum gaging plaster, except plaster must have a compressive strength of not less than 4,500 psi when tested dry in accordance with ASTM C472.

2.3.3 Gypsum Molding Plaster for Ornamental Plaster - ASTM C59/C59M.

2.3.4 Keene's Cement Finish Coat - ASTM C61/C61M.

2.3.5 Acoustical Plaster Finish Coat - ASTM E1042 Type [I,] [II,] Class A, noncombustible.

2.4 HYDRATED LIME

ASTM C206, Type S.

2.5 AGGREGATES

2.5.1 Sand for Gypsum Base Coats:

ASTM C35. Sand Gradation: Percentage retained by weight (plus or minus 2 percent) on each sieve.

Sieve Size Maximum Minimum

No. 4 0 0

No. 8 5 0

No. 16 30 5

No. 30 65 30

No. 50 95 65

No. 100 100 90

2.5.2 Sand for Gypsum Sand Float Finish:

ASTM C842. Sand Gradation: Percentage retained by weight (plus or minus 2 percent) on each sieve.

Sieve Size Maximum Minimum

No. 20 0 0

No. 30 0.5

No. 100 100 40

No. 200 100 70

2.5.3 Lightweight Aggregates, Perlite or Vermiculite for Gypsum Base Coat ASTM C35.

2.5.4 Silica Sand or Perlite Fines:

For use in lime-putty gypsum-gaged finish, aggregated white coat, must have the following gradation: 10 percent maximum retained on a No. 30 sieve, 4 percent minimum and 70 percent maximum retained on a No. 100 sieve, and 70 percent minimum and 100 percent maximum retained on No. 200 sieve.

2.6 WATER

Use only potable water , free of mineral and organic substances that affect the hardening and durability of the plaster or stucco.

2.7 PROPORTIONING

Unless specified otherwise, materials are specified on a volume basis and must be measured in approved containers, to ensure that the specified proportions will be controlled and accurately maintained during the progress of the work. Measuring materials with shovels (shovel count) is not being permitted. Prepare ready-mix gypsum plaster for use by the addition of water only.

2.7.1 Gypsum Base Coat Plaster

Use of sand or lightweight aggregate is optional in gypsum plaster basecoats, except provide (1) sand for Keene's cement and high strength gypsum-gaged finish coats; (2) lightweight aggregate when necessary for a required fire resistance rating.

2.7.1.1 Sand and Gypsum Plaster Base Coat

Mix scratch coat in the proportion of 100 lb of gypsum neat plaster to not more than 2 cu ft of damp loose sand; mix brown coat in the proportion of 100 lb of gypsum neat plaster to not more than 3 cu ft of damp loose sand; or scratch and brown coats may both be mixed in the proportion of 100 lb of gypsum neat plaster to not more than 2-1/2 cubic feet of damp loose sand.[ Mix the basecoats for double-up work in the proportion of 100 lb of gypsum neat plaster to[ not more than 2-1/2 cu ft of damp loose sand on gypsum lath][ and][ not more than 3 cu ft of damp loose sand on masonry].]

2.7.1.2 Lightweight Aggregate and Gypsum Plaster Base Coat

Mix scratch coat in the proportion of 100 lb of gypsum neat plaster to[ not more than 2-1/2 cu ft of lightweight aggregate on gypsum lath, and not more than 3 cu ft of lightweight aggregate on masonry. Mix brown coat in the proportion of 100 lb of gypsum neat plaster to not more than 2-1/2 cu ft of lightweight aggregate on gypsum lath and not more than 3 cu ft of light weight aggregate on masonry.

Where plaster thickness exceeds one inch, the aggregate proportion may be increased to 3 cu ft. Mix the basecoats in two-coat double-up work in the proportion of 100 lb of gypsum neat plaster to[ not more than 2-1/2 cu ft of lightweight aggregate on gypsum lath and not more than 3 cu ft of lightweight aggregate on masonry. Gypsum ready-mixed plaster with perlite aggregate may be provided in lieu of field-mixed lightweight aggregate and gypsum plaster, provided the specified proportion of aggregate to plaster does not exceed the proportion specified for field-mixed plaster.

2.7.1.3 Sand and Wood Fibered Gypsum Plaster Base Coat

Mix basecoats in the proportion of 100 lb of wood-fibered gypsum plaster to not more than one cu ft of damp loose sand.

2.7.1.4 Sand and High-Strength Gypsum Plaster Base Coat

Mix scratch coat in the proportion of 100 lb of high strength gypsum base coat plaster to not more than 2 cu ft of damp loose sand. Mix brown coat in the proportion of 100 lb of high strength gypsum basecoat plaster to not more than 3 cu ft of damp loose sand.

2.7.2 Gypsum Plaster Finish Coat

2.7.2.1 Lime-Putty

Prepare lime-putty in accordance with the printed directions of the manufacturer.

Use putty following preparation or following a soaking period as recommended by the manufacturer.

2.7.2.2 Lime-Putty Gypsum-Gaged (White Coat)

Use over sand and gypsum plaster or sand and wood-fibered gypsum plaster. Mix finish coat in the proportions of one part of gypsum gauging plaster to a volume of hydrated lime or lime putty. This mix is approximately equivalent to one 100 lb bag of gypsum gauging plaster to:

a. Not more than four 50 lb bags of hydrated lime, or

b. Not more than 4-1/2 cu ft of lime putty, or

c. Not more than 35 gal of lime putty.

2.7.2.3 Aggregated Finish Coat

Finish coat must consist of the lime-putty, gypsum-gaged finish specified herein with the addition of fine pulverized silica sand or perlite fines in the following proportions:

a. 1/2 cu ft per 100 lb bag of gypsum gauging plaster used in finish, or

b. 1/8 cu ft per 50 lb bag of hydrated lime, or

c. one gal per cu ft of lime-putty.

2.7.2.4 Gypsum Sand Float Finish

Mix finish in the proportion of one part neat unfibered gypsum plaster to not more than two parts of sand, by weight.

2.7.2.5 Keene's Cement Lime-Putty Finish

Mix finish in the proportion of not more than 100 lb of lime putty to100 lb of

Keene's cement.

2.7.2.6 High Strength Gypsum-Gaged Plaster Finish

Mix finish in the proportion of 200 lb of high strength gauging to 100 lb of hydrated lime.

2.7.2.7 Acoustical Plaster Finish

Mix finish in accordance with manufacturer's printed instructions.

2.8 MIXING

2.8.1 Job-Mixed Materials

Mix materials in mechanical mixers except finish coats containing lime may be hand mixed. Mechanical mixers must be an approved type that accurately and uniformly controls the quantity of water. When mixing by hand, mix dry plaster aggregate to a uniform color in the mixing box, add water, and hoe the plaster immediately into the water and mix thoroughly to a proper consistency. Water used for rinsing and cleaning containers and tools must not be used in mixing the materials. Sand proportions must be damp and in loose condition. A volume of damp loose sand must contain a minimum of

80 lb of dry sand in one cu ft. Mix the material while the mixer is in continuous operation in the following sequence:

a. Add maximum close to 90 percent of estimated quantity of water.

b. Add approximately one-half of the sand. If vermiculite or perlite is used, add all the aggregate.

c. Add cement and approved admixtures.

d. Add remainder of sand.

e. Mix with remainder of water as required. Mix until the mixture is uniform in color and consistency. Avoid excessive mixing and agitation. Discard gypsum plaster which has begun to set before it is used; do not permit retempering. Do not use frozen, caked, or lumped materials. Empty mixers and mixing boxes after each batch is mixed, and keep free of old plaster.

2.8.2 Ready-Mixed Packaged Materials

Mix ready-mixed packaged gypsum plaster in accordance with manufacturer's printed instructions.

2.9 BONDING AGENT

ASTM C631, interior application.

PART 3 EXECUTION

3.1 SURFACE PREPARATION

Clean surfaces before application of gypsum plaster of projections, dust, loose particles, grease, bond breakers, and foreign matter . Do not apply plaster directly to surfaces (1) of masonry or concrete that have been coated with bituminous compound or other waterproofing agents, or (2) that have been painted or previously plastered. Before plaster work is started, wet masonry and concrete surfaces thoroughly with a fine fog spray of clean water to produce a uniformly moist condition. Check metal grounds, corner beads, screeds, and other accessories carefully for alignment before starting work. Do not apply gypsum plaster to surfaces containing frost.

3.2 WORKMANSHIP

3.2.1 Slump Tests

Apply Plaster by hand or machine. When a plastering machine is used, control the fluidity of gypsum plaster to have a slump of not more than 3 inch when tested using a 2 by 4 by 6 inch high slump cone. Subsequent to determining water content to meet the specified slump, do not add additional water to the mix. Conduct the slump test according to the following procedure:

a. Place cone on level, dry, non-absorptive base plate.

b. While holding cone firmly against base plate, fill cone with plaster taken directly from the hose or nozzle of the plastering machine, tamping with metal rod during filling to release air bubbles.

c. Screed off plaster level with top of cone. Remove cone by lifting it straight up with a slow and smooth motion.

d. Place cone in a vertical position adjacent to freed plaster sample, using care not to shake or move base plate.

e. Lay a straightedge across top of cone, being careful not to shake or move cone.

Measure slump in mm inch from the bottom edge of the straightedge to the top of the slumped plaster sample.

3.2.2 Application

Apply gypsum plaster in three coats, except as follows:

Gypsum plaster applied to [masonry] [and] [gypsum lath] using the two-coat double-up method. Apply base coats with sufficient pressure and ensure plaster is sufficiently plastic to provide a strong bond to bases. Work base coats into screeds at intervals from 5 to 8 ft. Plaster must not be continuous across expansion and control joints occurring in walls, partitions, and ceilings. Finish work level, plumb, square, and true, within a tolerance of 1/8 inch in 8 ft, without waves, cracks, blisters, pits, crazing, discoloration, projections, or other imperfections. Form plaster work carefully around angles and contours, and well-up to screeds. Take special care to prevent sagging and consequent dropping of applications. There must be no visible junction marks in finish coat where one day's work adjoins another.[ Plastered surfaces to receive[ rubber or vinyl base coves][ wood base boards] must extend to wood ground indicated as backing for base.]

Plaster not required behind built-in cabinets and equipment[, and [_____]].

3.2.3 Control And Expansion Joints

[Install control joints at locations indicated before applying gypsum plaster. Vertical joints must be continuous and butt horizontal joints against the vertical joints. ]Check expansion, control joints and accessories to ensure unrestrained movement, metal lath not continuous behind the joints, and area between joints do not exceed 150 sq ft.

3.2.4 Curing

3.2.4.1 Gypsum Plaster

Before the plaster has set, provide environmental controls to prevent the plaster from drying too fast. After the plaster has set, provide for rapid drying to develop high strength.

3.3 GYPSUM PLASTER WORK

ASTM C842.

3.3.1 Gypsum Plaster Thickness Requirements

Plaster thicknesses are from face of metal lath plaster base (scratch coat) or solid base surfaces.

a. Vertical Surfaces:

Base Types Base Coat Finish Coat Total Thickness

Metal Lath 1/2 inch 1/8 inch 5/8 inch

Masonry 1/2 inch 1/8 inch 5/8 inch

Concrete 1/2 inch 1/8 inch 5/8 inch

Other Bases 3/8 inch 1/8 inch 1/2 inch

b. Horizontal Surfaces. Total plaster thickness for metal lath plaster, masonry and concrete bases is 5/8 inch. Total thickness of plaster for horizontal concrete surfaces is

1/8 to 3/8 inch.

c. Where vertical and horizontal concrete surfaces require more than 5/8 inch and 3/8 inch, to produce required lines or surfaces, [attach metal plaster base for plaster application] [as indicated].

3.3.2 Gypsum Plaster Basecoat Work

3.3.2.1 Gypsum Two-Coat System

Apply the first coat to cover the base with sufficient material and pressure to form a good bond on the wall or ceiling base. Before the first coat has set and without scratching or cracking the surface, apply a second coat (double back) of the same material proportion as the base coat to the screeds. Straighten to a true surface without application of water, and cross rake or scratch to receive the finish coat.

3.3.2.2 Gypsum Three-Coat System

Apply scratch coat 3/16 to 1/4 inch thick to cover the base with sufficient material and pressure to form a good bond on the wall or ceiling base. Rake or scratch the surface and allow to set firm and hard. Apply the brown coat to bring the base coat out to the screeds, compact and straighten to a true surface without the application of water, and cross rake or scratch to receive the finish coat.

3.3.3 Gypsum Plaster Finish Coats:

Moderately moisten or fog spray base coat of plaster that has become dry before finish coat is applied. Accelerate plaster, if necessary, to provide a setting time of not more than

4 hours from the time the plaster is mixed.

3.3.3.1 Lime-Putty and Gypsum-Gaged Finish Coats:

Apply lime-putty gypsum-gaged finish white coat or aggregated white coat [and high strength gypsum gaged finish] over the base coat, scratch in thoroughly, lay on well, double back, and fill out to a true, even surface. Allow the finish to dry a few minutes, then trowel well with water. Apply maximum pressure in order to compact the finish coat and provide a smooth finish free from blemishes and irregularities. Apply trowel finish coats of gypsum-gaged lime-putty over properly prepared base coats as thin as possible and 1/16 to 1/8 inch thick for conventional plaster system, except as necessary in spots to level out hollows in base coat.

3.3.3.2 Keene's Cement Lime-Putty Finish Coat: NOTE: Do not use Keene's cement as finish coat over a portland cement plaster basecoat, or on monolithic concrete, due to the probability of unsatisfactory bond between gypsum and portland cement materials.

Apply finish over gypsum-sand base coat only, scratch in thoroughly, lay on well, double back, and fill out to a true, even surface. Allow the finish to dry a few minutes, then trowel it well with water. Apply maximum pressure in order to compact the finish coat and provide a smooth finish free of blemishes and irregularities. Continue troweling until the finish sets.

3.3.3.3 Gypsum Sand Float Finish Coat:

Apply finish over the base coat, scratch in thoroughly, lay on with a trowel to an even surface, and then float with [_____] floats to a true, even surface, free of slick spots or other blemishes. Apply sand float finishes to a maximum thickness of 1/8 inch except as necessary to level out hollow spots.

3.3.3.4 Acoustical Plaster Finish Coat:

Apply finish in accordance with manufacturer's printed instructions and in the thickness necessary to provide the sound absorption coefficient specified, but not be less than 1/2 inch thick.

3.4 ORNAMENTAL PLASTER WORK

Complete ornamental work before the finish coat of plaster is applied to adjoining areas. Plaster for ornamental work must consist of a mixture that will produce satisfactory results for the respective conditions, be reinforced properly with fiber or zinc-coated steel wire netting as necessary to provide permanent construction, and be rigidly secured in place. Run plain moldings in place to templates and guides, with true radial lines for curved work; where it is not practicable to run such moldings, cast or run them on a bench and then secure in place firmly.

Cornices and moldings must be straight or curved, true to line, and corners neat.

3.5 PATCHING AND POINTING

Cut out and patch loose, cracked, damaged, or defective gypsum plaster. Patch must match existing work in texture, color and finish flush with previously applied gypsum plaster surfaces.

Point work abutting or adjoining finish work in a neat manner. Remove droppings or spatterings from surfaces. Leave clean and in a condition to receive paint or other finish. Remove protective covering from floors and other surfaces, and rubbish and debris from [the interior and exterior of] the building.

-- End of Section --