09220_en.doc

SECTION 09220

INTERIOR PLASTER

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 in the text by the basic designation only.

ITALIAN Laws

R.D. 2231 dated 16 Nov.1939 Norms for Acceptance of Limes.

R.D. 3 June 1968 New Norms for Acceptance Requirements and Test Methods on Cements

Decree of Ministry of Public Works, 31 August 1972 “Norms for Acceptance Requirements of Cement Agglomerates and Hydraulic Limes.

Italian National Institute for the Unification of Standards (UNI) Publications

UNI 2332-1

(1979) Test Sieves. Test Sieves and Relevant Receivers and Lids. Dimensions and Tolerances.

ITALIAN/EUROPEAN HARMONIZATION STANDARDS (UNI EN)(UNI ENV)(UNI EN ISO)

UNI ENV 413-1

(1994) Masonry Cement - Part 1: Specification

UNI EN 459-1

(2002) Building Lime - Part 1: Definitions, Specifications and Conformity Criteria

UNI EN 459-2

(2002) Building Lime - Part 2: Test Methods

UNI EN 932-1

(1998) Tests for General Properties of Aggregates - Part 1: Methods for Sampling

UNI EN 932-3

(1998) Tests of General Properties of Aggregates - Part 3: Procedure and Terminology for Simplified Petrographic Description

1.2

SUBMITTALS

Submit the following:

1.2.1 Product Data

Submit address and telephone number of the Manufacturer of products listed below.

Portland Cement

1.2.2 Samples

Exterior finish

Sample Panel

1.2.3 Manufacturer's Instructions

Ready-mix plaster

1.2.4 Requirements

Submit manufacturer's printed mixing instructions for ready-mix plaster finish.

1.3 QUALITY ASSURANCE

Finished plaster work shall 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 Portland Cement-Lime Plaster

Maintain an ambient temperature of not less than 4 degrees C continuously where plastering work will be performed. Maintain this temperature for not less than 48 hours prior to the application of plaster, while performing plastering, and during the curing operation. In interior plastering work, maintain heat within the building until normal occupancy conditions are established. When the building is exposed to hot dry winds or day-to-night temperature differentials of 10 degrees C or more, cover openings that are not glazed.

PART 2 – PRODUCTS

2.1 GENERAL

Products incorporated into this project shall meet the following requirements.

2.2 PORTLAND CEMENT

Provide gray portland cement with the following chemical composition:

Silicon dioxide 0.0%

Aluminum dioxide 0.0%

Ferric oxide 0.0%

Magnesium oxide 6.0% maximum

Sulfur trioxide 3.5% maximum

Loss on ignition 3.0% maximum

2.3 MASONRY CEMENT

Ministerial Decree dated 3 June 1968 and UNI ENV 413-1 natural in color.

2.4 HYDRATED LIME

R.D. 2331 dated 16 November 1939, UNI EN 459-1, and UNI EN 459-2.

2.5 AGGREGATES

2.5.1 Sand for Portland Cement Lime Plaster

UNI EN 932-1, UNI EN 932-3, and UNI 2332-1. except gradation of sand shall conform to the following requirements:

a. Sand Gradation for Basecoats:

Percentage Retained by weight

(plus or minus 2 percent) on each sieve

Sieve Size Minimum Maximum

No. 4 0

No. 8 0

No. 16 10

No. 30 30

No. 50 70

No. 100 95

b. Sand for Finish Coats: White and graded within the limits shown above for basecoats, except that the sand shall pass the No. 8 sieve, and for smooth finish the sand shall pass the No. 30 sieve.

2.6 WATER

Suitable for domestic consumption, and free of mineral and organic substances that affect the hardening and durability of the plaster.

2.7 PROPORTIONING AND MIXING

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

2.7.1 Basecoat Proportions

2.7.1.1 Portland Cement Plaster Basecoats

Mix scratch coat in proportion of one part by volume portland cement, not more than 3/4 parts by volume hydrated lime and 2 1/2 to 4 parts sand (volume of sand per sum of cement and lime). Mix brown coat in proportion of one part by volume portland cement, not more than 3/4 parts by volume hydrated lime and 3 to 5 parts sand (volume of sand per sum of cement and lime).

2.7.1.2 Scratch Coat for Ceramic Tile Backing

Mix scratch coat in the proportion of one part by volume of portland cement to 1/5 part by volume of hydrated lime, and 5 parts by volume of damp loose sand.

2.8 FINISH COAT PROPORTIONS

2.8.1 Cement Plaster Finish Coat

2.8.1.1 Color

Color of finish coat shall be white. Approved coloring compounds shall be added to produce the required color.

2.8.1.2 Texture

Texture shall be compatible with painting type “orange peel” or “satin” as shown on drawings. Color of finish coat shall be white. Approved coloring compounds shall be

2.8.1.3 Portland Cement-Lime Plaster Finish Coat

Mix finish coat in the proportion of one part by volume of portland cement to not more than one part by volume of hydrated lime, and not more than 4 parts by volume of damp loose sand. Workability shall govern the actual amount of lime and sand used in the finish coat, within the limits specified herein. Where smooth troweled finish is indicated, allow plaster to set up to the extent that it does not flow ahead or under the trowel, yet has not solidified. Trowel the face lightly to embed the granules. Do not over-trowel or burnish the surface.

2.8.1.4 Masonry Cement Plaster Finish Coat

Mix finish coat in the proportion of one part by volume of masonry cement to not less than 2 1/2 nor more than 3 parts by volume of damp loose sand.

2.9 MIXING

Mix materials in approved mechanical mixers of the type in which the quantity of water can be controlled accurately and uniformly, except that finish coats containing lime may be hand mixed. While the mixer is in continuous operation, add approximately 90 percent of the estimated quantity of water, half of the sand, and all of the cementitious materials.

Introduce the other one-half of the sand into the mixer in that same sequence and mix thoroughly with the remainder of the water until the mixture is uniform in color and consistency. Avoid excessive mixing and agitation. When vermiculite or perlite is used as the aggregate for gypsum plaster add the aggregate to the water before the plaster is added. Discard plaster which has begun to set before it is used; retempering will not be permitted. Do not use frozen, caked, or lumped materials. Empty mixers and mixing boxes after each batch is mixed, and keep free of old plaster.

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

2.10

ACCESSORIES

Corner beads, stops, control joints, and other accessories shall be stainless steel or galvanized steel, predrilled with flanges 2.5 centimeters wide, as minimum.

2.11 ACCEPTABLE PRODUCTS

Acceptable manufacturers that comply with this specification section are listed below:

1.

FARBE

Via Udine,63

33030 Maiano (UD)

Tel.: 0432-959406

Fax.: 0432-959219

2.

RIVVEK

Via Boscalto, 10/12

31023 Resana (TV)

Tel.: 0422-480045

Fax.: 0422-480022

3. RAN KOVER RK S.R.L.

Via Camatte, 1

37040 Zimella (VR)

Tel.: 0442-85700

Fax.: 0442-410974

PART 3 - EXECUTION

3.1 SURFACE PREPARATION

Clean surfaces to receive 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 plaster to surfaces containing frost. Check expansion and control joints and supporting metal structures to ensure that expansion and control joints can move unrestrained.

3.2 APPLICATION OF PLASTER

3.2.1 Application and Slump

Plaster may be applied by hand or by machine. When a plastering machine is used, control the fluidity of Portland cement-lime plaster to have a slump of not more than 65 mm when tested using a 50 by 100 by 150 mm 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 jiggle base plate.

e.

Lay a straightedge across top of cone, being careful not to vibrate cone. Measure slump in millimeters from the bottom edge of the straightedge to the top of the slumped plaster sample.

3.2.2 Workmanship

Apply plaster in three coats, except as follows:

a.

Provide scratch coat, or scratch coat with leveling coat, as backing for ceramic tile.

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 of from 1500 to 2400 mm. Plaster shall not be continuous across expansion and control joints occurring in walls, partitions, and ceilings. Finish plaster work level, plumb, square, and true, within a tolerance of one in 800 mm, 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 shall be no visible junction marks in finish coat where one day's work adjoins another.

3.3 PORTLAND CEMENT-LIME PLASTER

Apply base coats with sufficient pressure to curl the keys around the back of and to provide strong bond on masonry or concrete bases.

3.3.1 Scratch Coats for Plaster

Except at ceramic tile backing, apply in three coats to a thickness of not less than 15 mm. Apply the scratch coat not less than 5 mm thick, lightly score horizontally, and moist cure for not less than 24 hours.

Apply the brown coat after the scratch coat has been aged at least 24 hours in addition to the moist curing period. Apply the brown coat to bring the base coat out to the screeds, compact and straighten to a true surface with rod and darby, and float to receive the finish coat. After the brown coat has been moist cured for not less than 24 hours and aged at least an additional 5 days, apply the finish coat to a thickness of not less than 3 mm. Where previous coat has become dry, dampen the surface evenly with water, prior to the application of the next coat. The finish coat for plaster shall have a troweled finish. Moist cure plaster for 24 hours using a fine fog spray of water and apply to the finish coat as frequently as required to prevent dry-out of the plaster. Do not saturate the plaster to the point where free water stands on the surface. Prevent staining of the finish coat. Provide moist curing.

3.3.2 Scratch Coat for Ceramic Tile Backing

Apply scratch coat and keep continuously damp for not less than 24 hours before tile is to be set. Apply scratch coat in the thickness indicated or as necessary to bring the face of the tile to the required plane, but not less than 6 mm from the face of the material it is being applied to and with a level surface within a tolerance of one in 400 mm. Apply scratch coat after substantial grounds, plugs, hangers, and other such accessories have been installed for plumbing fixtures, electrical outlets, and other fixtures, and fittings have been installed that are to be secured to tiled surfaces. Apply scratch coat with sufficient pressure to ensure a proper bond and key with the base and a proper base for the setting bed. While the mortar is still plastic, cut the scratch coat with a trowel at internal vertical angles to the depth of the coat and for the full height of the tile bed, score horizontally or cross-scratch on 25 mm centers for the extent of the tile bed. Use mortar for scratch coats within one hour after mixing. At no time shall the mortar be retempered. Protect scratch coat and keep moist during curing period.

3.4

PATCHING AND POINTING

Upon completion of the building, cut out and patch loose, cracked, damaged, or defective plaster. Match patching of existing work in texture, color and finish flush with plaster previously applied. Point and patch plastered surfaces and plaster work abutting or adjoining other finish work in a neat manner. Remove plaster droppings or spatterings from surfaces. Leave clean, exposed plastered surfaces, in a condition ready to receive paint or other finish. Remove protective covering from floors and other surfaces, and rubbish and debris from the building.

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Section 09220

Section 09220