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SECTION 09210

GYPSUM PLASTER & INTERNALAND EXTERNAL RENDER SYSTEM

REVISION HISTORY

B 05.06.03 Clause 2.5.2 includedDavid

DugganPaul

RobertsRoger

Nickells

A 23.02.03 General RevisionsDavid

DugganPaul

RobertsRichardSmith

0 08.02.03Standard Specification Gypsum Plaster &Internal and External Render System

PhillBridger

PaulRoberts

RichardSmith

Rev Date Description Prepared

by

Checked

by

Authorised

by

WSA/D1204 Rev B/2003 09210/1 Gypsum Plaster & Internal and ExternalRender System

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WSA/D1204 Rev B/2003 09210/2 Gypsum Plaster & Internal and External

Render System

1 GENERAL

1.1 SECTION INCLUDES

1.1.1 The Contractor shall become familiar with other sections of the Specifications affecting workof this trade.

1.1.2 Furnish all labour, material, plant, equipment and appliances and perform all necessaryoperations required to execute the work of this section.

1.1.3 Gypsum plaster finish coat to plasterboard.

1.1.4 Internal and External sand cement render.

1.1.5 Priming of base material to be included.

1.2 RELATED SECTIONS

1.2.1 This schedule is intended to be used as a helpful indication of the related sections within theProject Specifications. It is not necessarily comprehensive or complete and it is theContractor's responsibility to ascertain all applicable sections required to understand the fullScope of Works intended.

Section 03300 Cast in Place Concrete Section 03411 PreCast Concrete

Section 04300 Unit Masonry System

Section 07900 Joint Sealers

Section 09200 Gypsum Board Systems

1.3 REFERENCES

1.3.1 The minimum standards for products specified in this section shall be relevant BSI standardsincluding but not limited to the following. Except as otherwise specified herein, perform workin accordance with specification codes and standards cited therein and to latest applicableaddenda and supplements.

BS 443 Galvanized Wire

BS 882 Aggregates

BS 890 Limes

BS 1191 Part 1 - Lightweight Plasters

BS 1191 Part 2 - Premixed Plasters

BS 1198 Sands - Internal Plastering

BS 1198 Sands - External Rendering

BS 1200 Sands for Mortars

BS 1202 Nails

BS 1369 Metal Lath

BS 1494 Part 2 Fixings

BS 1521 Waterproof Papers

BS 3148 Water for Plastering

BS 3416 & BS 6949 Black Bitumen Solutions

BS 6100-6.1 & 6.6.2 Glossary of Terms Internal Plastering

BS 4721 Ready-mixed Lime/Sand for Mortar

BS 4887 Mortar Plasticizers

BS 5262 Code of Practice for Render

BS 5492 Code of Practice for Internal Plastering

BS 6452 Beads for Plastering

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WSA/D1204 Rev B/2003 09210/3 Gypsum Plaster & Internal and External

Render System

BS EN ISO 1461 Hot Dip Galvanizing

BS 8000 Part 10 Code of Practice for Plastering and Rendering

BS 8290 Suspended Ceilings Metal Fixing Systems

1.4 SUBMITTALS

1.4.1 Submit under provisions of Section 01300.

1.4.2 Submit samples, specifications, description of system and installation method in accordancewith the Contract Documents. Submission shall indicate all dimensions, details ofconstruction, details of installation, relation and connections with adjoining work,reinforcement, welds, fastenings, anchorages and shop and site finishes.

1.4.3 Before submission of shop drawings submit to the Engineer a complete listing of testingagencies, manufacturers, fabricators and subcontractors for all types of plasterwork andrender.

1.4.4 Submit copies of reports of tests performed on the proposed products. Submit a list of

installations completed, where proposed products were used.

1.4.5 Submit, in accordance with the Contract Documents, to the Engineer copies of the informationfrom the manufacturer confirming compliance with the specification.

1.4.6 Certificate (in the form of standard data sheet or letter) that materials and products to beused comply with these specifications.

1.4.7 Submit samples of the specified plaster and render materials to show the surface texture andthe maximum range or variation in colour and shade, beads, movement joints etc.

1.5 QUALITY ASSURANCE

1.5.1 Perform Work in accordance with relevant British Standard.

1.6 QUALIFICATIONS

1.6.1 Applicator: Company specializing in performing the work of this section with minimum 5(five) years documented and proven experience approved by manufacturer.

1.7 MOCKUP

1.7.1 Provide mockup of Venetian plaster under provisions of Section 01400.

1.7.2 Provide mock up of colour through render from approved supplier.

1.7.3 Provide mockup of skim plaster to plasterboard.

1.7.4 Provide mockup of external sand cement render

1.7.5 Construct mockup on both concrete and blockwall within area to be agreed with Engineer.

1.7.6 Mockup may remain as part of the Work as agreed with Engineer.

1.8 ENVIRONMENTAL REQUIREMENTS

1.8.1 Do not apply plaster when substrate or ambient air temperature is less than 10 degrees C nor

more than 27 degrees C or as agreed with engineer.

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1.8.2 Provide water curing to external render as necessary.

2 PRODUCTS

2.1 MATERIALS

2.1.1 Plaster: Gypsum Plaster

Class B - natural gypsum/calcium sulphate from an approved source.

2.1.2 Water: Clean, fresh, potable and free of mineral or organic matter which can affect plaster.

2.1.3 Bonding Agent: type recommended for bonding plaster to concrete and concrete blocksurfaces.

2.1.4 Undercoat - 10mm gypsum plaster in single coat.

2.2 FINISHING PLASTER

2.2.1 3mm lightweight gypsum finishing plaster to BS 1191 Class B type B2 board finish plasters.

2.3 ACCESSORIES

2.3.1 Beads/stops for internal use to be galvanised steel to BS 6452.

2.3.2 Beads/stops for external use to be galvanised steel to BS 2989 designation Z2G450N andpassivated.

2.3.3 Dissimilar solid backgrounds for plaster.

2.3.4 200mm wide galvanised mesh strip for backgrounds in the same plane and galvanised cornermesh at internal angles fixed not more than 600mm centres along both edges.

2.3.5 Fasteners: Nails, staples, or other approved metal supports, of type and size to suitapplication, galvanized, to rigidly secure lath and associated metal accessories in place.

2.4 PLASTER MIX

2.4.1 Mix and proportion plaster and render in accordance with British Standards andmanufacturer's instructions.

2.5 EXTERNAL RENDER

2.5.1 15mm minimum 2-coat sand cement render base to primed block work.

2.5.2 Sand to lime to cement mix of 1.1.5 to 1.1.6.

2.6 INTERNAL RENDER

2.6.1 12mm minimum 2 coat sand cement render to primed blockwork.


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3 EXECUTION

3.1 EXAMINATION

3.1.1 Verify site conditions under provisions of Section 01100.

3.1.2 Verify that surfaces and site conditions are ready to receive work.

3.1.3 Masonry: Verify joints are cut flush and surface is ready to receive work of this section.Verify no bituminous or water repellent coatings exist on masonry surface.

3.1.4 Concrete: Verify surfaces are flat, honeycomb is filled flush, and surface is ready to receivework of this section. Verify no bituminous, water repellent, or form release agents exist onconcrete surface that are detrimental to plaster or plaster bond.

3.1.5 Acceptance of Backgrounds: Before starting preparation and applying coatings ensure thatbackgrounds are secure, adequately true and level to achieve specified tolerances, free fromcontamination and loose areas, reasonably dry and in a suitable condition to receive specifiedcoatings. Ensure that all cutting, chasing, fixing of concealed conduits, service outlets, fixing

pads and the like and making good of the background, are completed.

3.1.6 Remove efflorescence, laitance, dirt and other loose material by thoroughly dry brushing.

3.1.7 Remove all traces of paint, grease, dirt and other materials incompatible with coating byscrubbing with water containing detergent and washing off with plenty of clean water. Allowto dry before applying coatings unless specified otherwise.

3.1.8 Scrub in situ concrete surfaces with water containing detergent to ensure complete removal ofmould oil, surface retarders and other materials incompatible with coating. Rinse with cleanwater and allow to dry unless specified otherwise.

3.1.9 Grounds and Blocking: Verify items within walls for other sections of work have beeninstalled.

3.1.10 Mechanical and Electrical: Verify services within walls have been tested and approved.

3.2 PREPARATION

3.2.1 Dampen masonry surfaces to reduce excessive suction.

3.2.2 Clean concrete surfaces of foreign matter. Thoroughly dampen surfaces before using acidsolutions, solvent, or detergents to perform cleaning. Wash surface with clean water.

3.2.3 Roughen smooth concrete surfaces and smooth faced masonry.

3.2.4 Apply bonding agent in accordance with manufacturer's instructions.

3.3 INSTALLATION - ACCESSORIES

3.3.1 Continuously reinforce internal angles with corner mesh, return metal lath 75mm from cornerto form the angle reinforcement; fasten at perimeter edges only.

3.3.2 Place corner bead at external wall corners; fasten at outer edges of lath only.

3.3.3 Place strip mesh diagonally at corners of lathed openings. Secure rigidly in place.

3.3.4 Place metal lath over backing materials. Secure rigidly in place at centres of not more than


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600mm along both edges.

3.3.5 Place casing beads at terminations of plaster finish. Butt and align ends. Secure rigidly inplace.

3.3.6 Install frames plumb and level in opening. Secure rigidly in place.

3.3.7 Position to provide convenient access to concealed work requiring access.

3.4 CONTROL AND EXPANSION JOINTS

3.4.1 Locate expansion joints every 5m on external walls and in positions agreed with Engineerusing double casing bead spaced 3mm apart to form joint filled with 2-part polysolphide.

3.4.2 Coordinate joint placement with other related work.

3.5 PLASTERING

3.5.1 Apply gypsum plaster in accordance with relevant British standards and manufacturer'sinstructions.

3.5.2 Apply each coating firmly to achieve good adhesion and in one continuous operation betweenangles and joints. All coatings to be not less than the thickness specified, firmly bonded, ofeven and consistent appearance, free from rippling, hollows and ridges.

3.5.3 Finish surfaces to a true plane, to correct line and level, with all angles and corners to a rightangle unless specified otherwise, and with walls and reveals plumb and square.

3.5.4 Prevent excessively rapid or localised drying out.

3.5.5 Dubbing Out: If necessary to correct inaccuracies, dub out in thicknesses of not more than10mm in same mix as first coat. Allow each coat to set before the next is applied. Crossscratch surface of each dubbing out coat immediately after set. Dubbing out will not bepermitted on smooth dense concrete surfaces except as recommended by the plastermanufacturer.

3.5.6 Undercoats generally to be not less than 8mm thick with thicknesses greater than 16mmapplied as two equal coats. Rule to an even surface and cross scratch each coat to provide akey for the next hand-applied coat.

3.5.7 Apply finish coat to minimum 3mm thickness.

3.5.8 Smooth Finish: Trowel or float to produce a tight, matt, smooth surface with no hollows,

abrupt changes of level or trowel marks. Do not use water brush and avoid excessivetrowelling and over polishing.

3.5.9 Perform work in panels to nearest natural break or between accessories.

3.6 TOLERANCES

3.6.1 Maximum Variation from True Flatness: 3mm in 3 m.

END OF SECTION
