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FINISHING 7

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F I N I S H I N GINTRODUCTION

TECHNICAL ENQUIRYLINE t 01275 377789 f 01275 377456 www.lafargeplasterboard.co.uk

Lafarge Finishing Systems

Lafarge Deco System*

The Lafarge Deco system is a uniquefinishing system comprising pre-sealed plasterboard and a pre-sealedjoint compound. Once installed andjointed the Deco system is ready fordecoration, eliminating the need fora coat of sealer.

Lafarge Taping and Jointing

The Lafarge Taping and Jointingsystem is used for the seamlessjointing of plasterboards. Oncejointed, the finished surface shouldbe sealed ready to accept directdecoration.

Lafarge Supreme Skim Plaster

Lafarge Supreme Skim plaster is agypsum based high quality plasterfinish for skim plastering toplasterboard.

Lafarge Universal Texture

Lafarge Universal Texture provides acrack-resistant textured, decorativefinish to interior walls and ceilings.

Note:

* Lafarge Plasterboard does notrecommend the use of gloss,eggshell, silk or sheen paints in-linewith BS 8212: 1995. However, shouldyou choose to use such finishes,Lafarge recommend the use of anadditional coat of Lafarge UniversalSealer on the Deco Systems.

The use of matt finish paints arelikely to produce a superior finish.

Contents

The Deco System 287

Taping and jointing 291

Skim plastering 301

Texture 305

Ready reckoner 308

System selection

Common application areas:

Residential: New Housing■ ■ ■ ■

Flats■ ■ ■ ■

Renovation■ ■ ■ ■

Commercial: Offices■ ■ ■

Entertainment■ ■ ■

Institutional■ ■ ■

Shops■ ■ ■

Industrial: Factories■ ■ ■

Warehouses■ ■ ■

Specials: Cinemas■ ■ ■

Hospitals■ ■ ■

Lafa

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F I N I S H I N GDECO SYSTEM

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Deco is a range of pre-sealed boardsand colour-matched joint cementswhich create a consistent white finishready for final decoration.

As the boards are factory-sealed there isno requirement for a separate sealer*coat to be applied on-site, translating totime and labour savings.

The Deco range includes threewallboards:

• Predeco, for ‘standard’ applicationssuch as housing

• Megadeco, which meets the highersystem performance requirements ofcommercial, industrial environments,hospitals and schools

• Hydrodeco, for use where moistureresistance is needed.

* Lafarge Plasterboard does not recommend the use of gloss, eggshell, silk or sheenpaints in-line with BS 8212: 1995. However, should you choose to use such finishes,Lafarge recommend the use of an additional coat of Lafarge Universal Sealer on theDeco Systems.

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Lafarge Deco SystemThe Lafarge Deco system is acomplete lining and finishingsystem, used as a quality alternativeto conventionally sealed wallboards.

The Deco system consists of a pre-sealed wallboard used with PredecoJoint Filler and Deco Joint Cement.

The Deco system uses a factory-sealed paper board liner with aunique purpose-designed coating,combined with colour matched jointcements so that, once constructed,linings and partitions have a pre-sealed consistent white appearanceready for final decoration.*

The Deco wallboard and Decojointing compounds togetherprovide a wallboard surface readyfor direct decoration without theneed for site-applied drywall sealersand primers.

The environmental performancecriteria, cutting and fixing of Decowallboard are identical to those ofstandard wallboard.

Components

The main components of the systemare:

• pre-sealed wallboard

• special pre-sealed jointingcompounds

• pre-sealed cove

LimitationsThe Deco system is not compatiblewith a plaster finish.

*Paint application

Lafarge Plasterboard does notrecommend the use of gloss,eggshell, silk or sheen paints in-linewith BS 8212: 1995. However, shouldyou choose to use such finishes,Lafarge recommend the use of anadditional coat of Lafarge UniversalSealer on the Deco Systems.

The use of matt finish paints arelikely to produce a superior finish.

Introduction

Table 7.1 Deco System ComponentsPredeco Joint Filler Description Pack size

12.5 kg bags

Deco Joint Cement Description Pack size

20 kg

Deco Machine Description

20 kg

Predeco Description

Megadeco Description

Hydrodeco Description

Lafarge Predeco Cove Description

A unique setting compound for bedding tapesand filling joints on the Deco range of boards. It must be over coated with Deco Joint Cement or Deco Machine.

Also for bedding Lafarge Tape-On Corner beadsand Lafarge Flex Tape.

A unique pre-mixed two-coat, air-drying cement.Designed for bedding tapes and finishing jointson the Deco range of boards. Can be applied byhand or mechanical jointing and sanded with150/120 grit sandpaper.

Lafarge wallboard with Deco pre-sealed surface.

Combines properties of Firecheck, dBcheck andToughcheck with Deco pre-sealed surface.

Lafarge Moisturecheck with Deco pre-sealedsurface.

Lafarge Cove with Deco pre-sealed surface.

A unique pre-mixed air-drying cement designedfor bedding tapes and finishing joints on theDeco range of boards. Formulated for usethrough automatic taping tools. Sand with150/120 grit paper. May be hand applied.



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Application details

Table 7.2 Jointing compound suitabilityProduct Bedding Second Finishingname coat coat coat

Pre-Deco Joint Filler ✓ ✓ –

Deco Joint Cement ✓ Not needed ✓

Machine Deco Joint Cement ✓ ✓ ✓

Jointing Methods

2 x Deco Filler & 1 x Deco JointCement – Ref TJ17

• Most widely used combination. Asthe filler has a setting time of 90 minutes this allows the secondcoat to be over-coated in 90 minutes

• Deco Joint Cement must be usedto provide the pre-sealed featuresof the system. There are bothmachine and hand appliedversions available

• Final coat of Deco Joint Cementor Deco Machine Joint Cement,drying time vary on atmosphericconditions because this is an air-drying compound

Full operation with Deco JointCement/Deco Machine JointCement – Ref TJ18

• Mostly used where machinetaping is required

• Drying time vary on atmosphericconditions because this is an air-drying compound

Other jointing products on Decoboards

• Only those compounds shown intable 7.2 are suitable on Decoboards. Lafarge cannot warrantythe adhesion of other compoundsto Deco boards.

The Deco System is not compatiblewith a plaster finish.

Deco System – Tape and joint operation complete

Traditional system – Tape and joint operation complete

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Specification clauses

Lafarge Deco SystemTaping and jointing the decoratingface of Lafarge Deco pre-sealedplasterboards.

Additional Clauses

Add general clauses, see Section 8, ifrequired, for:

• Health and Safety

• Storage and materials

• Site conditions and workmanship

NBS clauses

When using the NBS Specification,use clause K10 PLASTERBOARD DRYLININGS/PARTITIONS/CEILINGS.

The Lafarge Plasterboard websitecontains a full set of NBS clauses,completed for each LafargePlasterboard system. See:www.lafargeplasterboard.co.uk/nbssearch/index.asp

Location ……………………………………Client reference ……………………………………Joint TapeLafarge Paper Joint Tape, width 50mm with centre crease.

Edge BeadsLafarge Edging Bead, reference BEAD EDGE ………, or

Lafarge Tape-Ons Stop Bead ……… mm.

Internal/external corner protectionLafarge Flex Tape for external angles, or

Lafarge Tape-On Beads Type ……… for internal/external angles.

Edge Beads and Tape-Ons manufactured in accordance with requirements ofBS 8212: 1995.

Jointing compoundsPredeco Joint Filler

Deco Joint Cement

Deco Machine Joint Cement

ApplicationApplication to be in accordance with Lafarge Plasterboard’s instructions. Vinylbased compounds may be applied over gypsum based bedding coats, butgypsum based compounds must not be applied over vinyl based compounds.

Finished tolerancesFinished tolerances to be in accordance with BS 8212: 1995 section 3, figure 3.

Materials and InstallationAll materials unless otherwise indicated shall be supplied by LafargePlasterboard Ltd, and shall be installed in accordance with their currentliterature and in accordance with BS 8212: 1995.

Notes:

Red text lists alternative productspecifications.

(Italic red text within bracketsgives advice on selecting theinformation needed).


F I N I S H I N GTAPING AND JOINTING

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Taping and jointing is the quick, professional, quality approachto finishing drywall systems. Purpose-designed tape bedding and filling compounds, offer either three coat or two coatformulations, are markedly quicker and require less drying time,than skim plastering.

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Lafarge Taping and JointingSystemLafarge Taping and Jointing systemis used to create continuous seamlessplasterboard walls and ceilings usingeasy application methods, includingtwo stage systems. It is used forjointing:

• Tapered edge wallboard

• All internal and external cornerjoints

• Lafarge Fresco

• Lafarge Profiles

Jointing Compounds

Product TypesThere are three different types ofjoint compounds:

Air-drying:

• New Pure Velvet

• Readymix Lite

• FineForm Mid-Weight

• Rapid SandAir-drying products are limestonebased. Drying times will depend onclimatic conditions.

Lafarge offer both powderedproducts (New Pure Velvet andRapid Sand) and ready mixedproducts (FineForm Mid-Weight andReadymix Lite)

Air-drying compounds are oftenused as the finishing coat due to theproduct being easy to sand. Theycan also be used for bedding andfilling.

Air-drying products are not suitablefor Flex Tapes or Tape-on beads andshould not be used as a sub coatprior to the application of settingcompounds.

Setting Compounds:

• Fast SetFast Set is a gypsum-based jointingcompound with a 90 minute settime. Fast Set should be used for thebedding and filling coats during thejointing process. Fast Set is notrecommended as a finishing coat, asit is difficult to sand.

Drying/Setting Compounds:

• Easy FinishEasy Finish combines the qualities ofair-drying and setting compounds. Itis a gypsum-based product with a 90minute set time, but unlike Fast Set,it can be used as a finishing coat asit is easily sanded. With Easy Finishthe jointing process can becompleted in two stages instead ofthe usual three.

Introduction

Table 7.3 Jointing compoundsFast Set Description Pack size

12.5 kg bags

Easy Finish Description Pack size

10 kg bags

Rapid Sand Description Pack size

22.5 kg bag

New Pure Velvet Description Pack size

25 kg bags

FineForm Mid-Weight Description Pack size

20 kg bucket

Readymix Lite Description Pack size

20 kg bucket

Joint Tape Description Pack size

150m roll

Flex Tape Description Pack size

33m roll

Corner 90º Tape-On Bead Description Pack size

50 lengths

per carton

Sanding Paper Description Pack size

Packs of 50 sheets

Gypsum based jointing compound with a 90 minutessetting time for bedding tapes and filling joints.

Also suitable for bedding Lafarge Tape-on Cornerbeads and Lafarge Flex Tape.

Fast Set cannot be used in automatic tapingmachines. Sand with 120 grit paper.

An air-drying lightweight powder compound forhand or machine application.

A light weight air-drying compound for beddingtapes and finishing joints, either by hand orusing a machine. Rapid Sand allows the jointingoperation to be completed in two stages. Sandwith 120/150 grit paper.

Vinyl based pre-mixed jointing compound forair-drying applications. Suitable for beddingtapes and finishing joints by the Premier orsimilar automatic taping tools or by hand.Sand with 120 grit paper.

A setting/drying compound for hand jointingonly. It cannot be used in automatic tapingmachines. Used for bedding external cornerprotection (Lafarge Tape-on-Corner Beads andLafarge Flex Tape), bedding tapes and finishingjoints. Sand with 120/150 grit paper.

A lightweight air-drying pre-mixed jointcement for hand or mechanical jointing.Used for bedding tapes and finishing joints.Two coat application due to low shrinkageformulation. Sand with 120 grit paper.

White perforated cross-fibre paper tape forreinforcing joints. Suitable for hand ormechanical application with Lafarge jointingcompounds.

Silicon carbide open coat 120 and 150 gritsanding paper. For use with hand or polesanders. Size 100 x 250mm.

An air-drying powdered compound for beddingtapes and finishing joints as a three-stageapplication not suitable for bedding cornerprotection. Can be applied over Fast Set as afinish and sanded with 150 grit paper.Can be applied by hand or mechanical methods.

Flex Tape is cross fibre paper tape reinforcedwith rust-resistant steel strips for theprotection of irregular external corner angles.

Wax coated pre-formed 90º corner protectionTape-On bead, paper tape reinforced withgalvanised metal for protection of externalcorners and board edges.



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Application details

Table 7.4 Use of jointing compoundsCorner Bedding Filling Finishing Sandingtape tape coat coat paper

Fast Set ✓ ✓ ✓ ✗ 120 grit

Rapid Sand* ✗ ✓ Not required ✓ 150 grit

FineForm Mid-Weight* ✗ ✓ ✓ ✓ 120 grit

New Pure Velvet ✗ ✓ ✓ ✓ 150 grit

Easy Finish ✓ ✓ Not required ✓ 120 grit

Readymix Lite* ✗ ✓ Not required ✓ 150 grit

* Whilst air-drying compounds are suitable for filling joints, it is necessary to leave adequate drying time between each coat.

Tapered edge board jointing

Lafarge Joint Tape beddedin Lafarge jointingcompound

Jointing compound struckoff flush with the face ofplasterboard

Final coat of jointingcompound feathered out50 to 60mm beyondsecond coat

Second coat of jointingcompound feathered out50 to 60mm beyond firstcoat

Allow to set hard or dry fully, thenapply a second coat of jointingcompound over the joint, featheringout 50 to 60mm beyond the edgesof the first coat. Allow this to sethard or dry fully, then complete thejoint with a further coat of jointingcompound feathered out 50 to60mm beyond the second coat.

Finally, finish the joint by sandingsmooth with Lafarge 120 or 150 gritsanding paper and seal the entirewallboard surface and joint withLafarge Universal Sealer or, if avapour control layer of no greaterthan 15 MNs/g is required, two coatsof Lafarge Drywall Sealer may beapplied to the finished surface.

JointingIt is recommended that jointing iscarried out in the followingsequence:

1. Internal angles

2. Tapered edge joints

3. Cut edge joints

4. Finally external angles.

Jointing can be carried out manuallyor by Premier Internationalautomatic taping machine usingLafarge compounds and tapes.

Lafarge manufacture three types ofjoint compounds:

• Air-dying compounds

• Setting compounds

• Combined drying/settingcompounds.

Air-drying compounds are RapidSand, FineForm Mid-Weight andReadymix Lite. These compoundsare suitable for use in PremierInternational automatic taping toolsor similar machine application.

Setting compounds such as Fast Setcan be used to increase the speed ofthe jointing process. Use Fast Set tobed the tapes and fill the joints.Once dry over coat with an air-drying compound.

Easy Finish is a 2-coat drying/settingcompound, which is used to fill andfinish the joint in two coats.

Setting compounds may not be usedin automatic taping machines unlessthe machines are designed to acceptsetting compounds.

Never use air-drying compoundsbeneath setting compounds, as thebedding coat may not dry outproperly.

Tapered edge board joints: hand application

Apply Lafarge Jointing Compoundto the joint. Cut Lafarge Joint Tapeto length, centre the tape over thejoint and press the tape firmly intothe compound.

Lafarge Joint Tape is ready creasedfor use on internal angles; alwaysbed the face with the crease lineinto the compound. Take care toavoid trapping air bubbles andensure that there is at least 1mmbed of jointing compound and strikeoff flush with the plasterboard face.

Two Coat compounds (Easy Finish,Readymix Lite and Rapid Sand)

Apply compound to the joint. CutLafarge Joint Tape to length, centrethe tape over the compound andpress the tape firmly into thecompound. Take care to avoidtrapping air bubbles and ensure thatthere is at least a 1mm bed ofcompound and strike off (fill) flushwith the plasterboard face. Allow todry fully, and apply a second coat ofthe same compound over the firstfeathering out 50-60mm beyond theedges of the first coat.

Finally finish the joint by sandingand sealing as detailed before.

300mm approx

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Application methodsThe type of product used depends on the way the jointer works. Jointers fall into two categories:

Hand taping and jointing Machine jointing – Premier International automatic taping tools

Flat joints Paper tape Paper tape bedded with air-drying compound (always air-drying compound)

Covered in two coats of setting compound or one coat followed by 7”, 10” or 12” boxes

of setting compound and one coat of air-drying joint cement

Finished with one coat of air-drying joint cement

Internal corners Paper tapes bedded with air-drying or setting compound Paper tapes bedded with air-drying compound

Covered with setting or air-drying joint cement Finished with air-drying compound

Finished with one coat of air-drying joint cement

External corners Flex tape bedded with setting compound Flex tape bedded with setting compound

Filled with setting or air-drying joint cement Filled with setting compound or air-drying joint cement

Finished with one coat of air-drying joint cement Finished with air-drying joint cement

Application details

Flat joints – tapered edge

Flat joints – square and cut edge joints

Jointingcompound

Lafarge JointTape bedded inLafarge jointingcompound

First coat of LafargeJointing Compoundstruck off withplasterboard face

Second coat of Lafargejointing compoundfeathered out beyondfirst coat

Finishing coat ofLafarge jointingcompound featheredout 50 to 60mmbeyond second coat


LafargeJointingcompound

Fill withLafargeFast Set

Square edgewallboard

Tapered edgewallboard

First coat of Lafargejointing compounddown edge of JointTape

Second coat of Lafargejointing compoundfeathered out beyondfirst coat

Finishing coat ofLafarge jointingcompound featheredout onto plasterboardface

200mm

200mm

300mm approxNote: If using a two coat Lafargejointing compound product thereis no requirement for the secondcoat process



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Application details

Internal angles

External angles

Jointingcompound


First coat of jointingcompound struck offwith plasterboard facewith the tape beddedinto compound

Second coat of jointingcompound featheredout beyond first coat

Finishing coat ofjointing compoundfeathered out beyondsecond coat

LafargeFast Set orEasy Finish

Lafarge Tape-On Beador Lafarge Flex Tapebedded in

First coat of LafargeFast Set or Easy Finishfeathered out with thetape bedded intocompound

Second coat of LafargeFast Set or final coatof Easy Finishfeathered out

Final coat of jointingcompound featheredout if using a threecoat application

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Corner and edge protectionProper treatment of corners andedges is very important. LafargeTape-On gives a superior appearanceand stronger finish that resistsimpact and cracking forces. Itcombines the ease and speed ofapplication of a flexible tape withthe strength of a rigid bed. Theexposed paper surface gives goodjointing compound adhesion.

Tape-On Corner

For sharp external angles.

External angle 90º, supplied in 2400and 3000mm lengths.

External Corners

Protect external angles with LafargeTape-On rigid corners. For small orirregular reveals and angles useLafarge Flex Corner Tape.

Apply a 50mm wide band of FastSet on each side of the angle. Cutthe corner section to length and bedin around the angle. Strike off flushwith the plasterboard face, thenallow to set hard. Apply furthercoats of jointing compound asabove.

Follow a similar procedure forLafarge Flex Corner Tape.

NOTE: Taping and jointing shouldnot be carried out at extremetemperatures (greater than 40ºC or less than 5ºC). Do not tape and joint on frozenbackgrounds.

Application details

Tape-On Corner, 90º external corner

Two layer board layout, externalcorner

Tape-On Stop Bead 9.5 and 12.5mm

Edge Bead 9.5 and 12.5mm

Machine application

In automatic taping machines alwaysuse Lafarge FineForm Mid-Weight,Rapid Sand or Readymix Lite. Donot use a setting compound such asLafarge Fast Set and Easy Finish.This may be used only in thefinishing boxes designed to acceptsetting compounds.

Vertical joints

Run the machine up from thebottom of the wall, maintainingcontact with both wheels. Stop andcut the tape 100mm from the ceilingbefore completing the run. Wipedown tapes with a broad knife andallow to dry.

Ceiling joints

Tape butt joints before taperededge joints. For the first 150mmkeep both wheels on the surface tobed the tape, then tilt the machineslightly so only one wheel is incontact and move the machinebackwards. Tilting the machine willminimise spillage. Replace bothwheels on the surface before cuttingthe tape and completing the run.Wipe down tapes with a broad knifeand allow to dry.

Finishing

Apply the first finishing coat with175mm (7”) box. Start vertical jointsat the ceiling and run down toabout knee height. Lock the handleand run the box back up from thefloor to complete the joint. Onceiling joints run to about 700mmfrom the opposite wall beforereversing the direction of the box.

Final coats are applied with 250mm(10”) and 300mm (12”) boxes. Thejoint cement must be dry beforeapplying a further coat. Adjust thecrown on each box to distribute thecorrect amount of compound foreach coat.

Nail spotting

Use the nail spotter to fill all nailand screw depressions.

Sand with Lafarge 120 or 150 gritSanding Paper and seal with LafargeUniversal Sealer or Lafarge DrywallSealer.

Cut edge joints

Keep cut edge joints to a minimum.If exposed cut edges cannot beavoided treat edge with a PVACbonding agent prior to jointing.Lightly sand cut edges to removeany paper burrs. Carry out jointingas for tapered edges.



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Application details

Jointing Methods – 3 coat

2 x Fast Set & 1x Rapid Sand orNew Pure Velvet – Ref TJ10

• Most popular system as thecomponents are the most costeffective to combine, popular innew housebuilding.

• 3 coat system

• First two coats will set in 90 minutes per coat

• Final coat of New Pure Velvet orRapid Sand, drying time variesdepending on atmosphericconditions

• New Pure Velvet or Rapid Sandused to “top out” the joint as it is a finer and easier to finishcompound and Fast Set is only for filling and bedding

• The final coat can be machineapplied

2x Fast Set & 1x FineForm Mid-Weight– Ref TJ11

• Popular method for contractorswho prefer to use ready mixedcompounds to finish

• 3 coat system

• First two coats will set in 90 minutes per coat

• Final coat of Fine From Mid-weight, drying time variesdepending on atmosphericconditions

• Readymix used to “top out” thejoint as it is a finer and easier tofinish compound and Fast Set isonly for filling and Finishing

• The final coat can be machineapplied

3 x Readymix – Ref TJ16

• 3 stage application

• May be machine or hand applied

• Drying time on each coat will be dependent on atmosphericconditions as FineForm Mid-Weightis an air-drying compound

Jointing Methods – 2 coat

2 x Readymix Lite – Ref TJ12

• 2 coat application due to very lowshrinkage properties of ReadymixLite

• Machine or hand appliedapplication

• Drying time varies depending onatmospheric conditions

• Readymix Lite is an easy to sandcompound

2 x Easy Finish – Ref TJ13

• 2 coat application due to lowshrinkage properties of EasyFinish

• Hand applied only due to set time(90 minutes)

• Full operation possible as EasyFinish is easy to sand

• Cost effective and quickcombination

• Joints can be completed in 180 minutes

1 x Easy Finish & 1 x ReadymixLite – Ref TJ14

• 2 coat application due to lowshrinkage properties of bothproducts

• Final coat can be 10” or 12”boxed by machine or handapplied

2 x Rapid Sand – Ref TJ17

• 2 coat application

• May be machine or hand applied

• Drying time on each coat will bedependent on atmosphericconditions as Rapid Sand is an air-drying compound

Note: The second coat of any 3 coat jointing method can be replaced using asuitable air-drying joint cement.

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Lafarge Taping and JointingSystemsTaping and jointing the decoratingface of plasterboards using LafargeJoint Tape and Lafarge jointingcompounds.

Additional Clauses





NBS clauses



Location ……………………………………Client reference ……………………………………Joint TapeLafarge Paper Joint Tape, width 50mm with centre crease.

Edge BeadsLafarge Edging Bead, reference BEAD EDGE ………, or

Lafarge Tape-Ons Stop Bead ……… mm.

Internal/external corner protectionLafarge Flex Tape for external angles, or

Lafarge Tape-On Beads Type ……… for internal/external angles.

Edge Beads and Tape-Ons manufactured in accordance with requirements ofBS 8212: 1995.

Jointing compoundsLafarge Fast Set

Lafarge New Pure Velvet

Lafarge FineForm Mid-Weight

Lafarge Easy Finish

Lafarge Readymix Lite

Lafarge Deco Joint System

Lafarge Rapid Sand

(Note: Use only Lafarge Fast Set to bed Lafarge Tape-On Corner Protection.)

Sealer coatLafarge Drywall Sealer or Lafarge Universal Sealer applied across wholedrylined surface by brush/roller in one/two coats to coverage raterecommended by Lafarge. (One coat is sufficient for decorating. Two coats ofLafarge Drywall Sealer will provide a small amount of vapour resistance.)

ApplicationApplication to be in accordance with Lafarge Plasterboard’s instructions. Vinylbased compounds may be applied over gypsum based bedding coats, butgypsum based compounds must not be applied over vinyl based compounds.

Finished tolerancesFinished tolerances to be in accordance with BS 8212: 1995 section 3, figure 3.


Notes:





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Installation

Internal AnglesUsing a 4” tapingknife, apply jointingcompound to bothsides of internal angle.

Internal AnglesBed paper joint tapeinto corner and covertape with jointingcompound, strikingoff flush with theplasterboard face.

Internal AnglesWhen tape has sethard or fully dried,apply a second coat of jointing compound,feathering out beyondthe edges of thefirst coat.

Internal AnglesWhen set hard andfully dried, apply afinishing coat of air-drying compound,feathering outbeyond the edges ofthe second coat.Now allow joint todry fully.

Tapered JointsApply jointingcompound totapered joint.

Tapered JointsBed paper joint tapeinto the compoundand cover tape withjointing compound,striking off flush withthe plasterboard face.

1

2

3

4

5

6

Tapered JointsWhen set hard orfully dried, apply a second coat ofjointing compound,feather out beyondthe edges of the first coat.

When set hard or fullydried apply a finishingcoat of air-dryingcompound,feathering outbeyond the edges of the second coat. Now allow joint todry fully.

Square EdgeJointsWhen taping squareor cut edges, afterbedding the tapeapply a 200mm bandof jointing compounddown the edges ofeach side of the joint tape.

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8

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External AnglesUsing a 4” tapingknife, apply a 50mmwide band of FastSet or Easy Finishon each side of the angle.

External AnglesBed tape onto thecorner. Once bedded,cover each side ofthe tape with a100mm band of FastSet or Easy Finish,feathered out ontoplasterboard face.

Apply a second coatof Fast Set or EasyFinish, feathered out50 to 60mm beyondthe edges of the firstcoat.

External AnglesWhen set hard, apply a finishing coat of air-dryingcompound or EasyFinish, feathered out 50 to 60mmbeyond the secondcoat.

Now allow to dryfully.

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Installation

Square EdgeJointsWhen set hard orfully dried, apply a second coat ofjointing compound250mm wide, downthe edge of each sideof the joint tape.

Square EdgeJointsWhen set hard orfully dried, apply a finishing coat of air-drying compoundover the entire joint,covering tape andfeathering out ontoplasterboard face.

Square EdgeJointsUsing a LafargeJointing Sponge,clean all edges ofjointing compoundon finishing coats to minimise sanding.Now allow joint todry fully.

External AnglesUsing tin snips, cutLafarge Flex Tape tolength. Pre-creasetape so that the heatbonded metal stripsface in towardsplasterboard.

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10

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12 Installation details on Lafargesystems are also available in theLafarge Installation Guide oronline at: www.lafargeplasterboard.co.uk


F I N I S H I N GSKIM PLASTERING

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Lafarge plasterboards are designed toaccept skim plasters with ease,allowing this approach to finishing tobe adopted wherever a ‘traditional’appearance is preferred.

Skim plastering offers little benefitover drywall finishing using taping andjointing techniques but remainspopular in some parts of the country.

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Lafarge Supreme SkimPlasterLafarge Supreme Skim is an ivorycoloured gypsum based finishplaster for internal use. It can beapplied to plasterboardmanufactured to BS 1230: Part 1: 1985to produce a high quality finish.Lafarge Supreme Skim should beused on Lafarge plasterboard ivoryface.

• Suitable for use on most types ofplasterboard

• If Moisture Resistant plasterboardis to be skimmed, a coat of50%PVA/water must be appliedand skimmed whilst tacky

• Not suitable for use on sand andcement backgrounds

• Not suitable for use on gypsumbacking coat plasters

Authority

Lafarge Supreme Skim conforms toBS 1191: Part 1: 1973, GypsumBuilding Plasters, Class B, Types b1and b2.

Composition

Lafarge Supreme Skim is a newgeneration formulation of materials,based on gypsum semi-hydrateproducing a high standard plasterproduct.

Lafarge Supreme Skim’s uniquecharacteristics enables it to be mixedmore easily than other plasters, andless powder is used for the samecoverage. It is also easier to applyand can be trowelled to a matt orsemi-polished finish.

Size

Lafarge Supreme Skim is supplied in25 kg bags.

Fire Protection

Lafarge Supreme Skim, when testedto BS 476: Part 4: 1970 and EuroclassA1 is classed as non combustible andsatisfies the requirements for Class 0in accordance with the NationalBuilding Regulations 1992, and theBuilding Standards (Scotland)Regulations 1990, when tested to BS 476: Part 6: 1981 and Part 7: 1971.

Conditions of use

Lafarge Supreme Skim should beused in accordance with BS 5492:1990, Code of Practice for InternalPlastering, and BS 8000: Part 10: 1989.However, the surface temperature inuse must not exceed 40ºC.

For full details see table 7.5.

Plasterboards

Ivory face

Lafarge Supreme Skim should beapplied to a minimum thickness of2mm. Joints to be reinforced withLafarge Joint Tape.

Grey face (Baseboard and Lathonly)

Lafarge Supreme Skim should beapplied to a minimum thickness of3mm. Joints to be reinforced withLafarge Joint Tape.

Mixing

All tools and buckets should beclean and all water used should beof drinking quality.

Sprinkle Lafarge Supreme Skim,minimising dust, onto the water andmix to a suitable creamy consistency,ensuring no lumps remain.

Lafarge Supreme Skim plastershould always be mixed in wellventilated conditions.

Application

This is the recommended six stepmethod for skimming plasterboard.The italic text denotes the LafargePlasterboard best practicerecommendation.

1 Board InstallationFix the wallboard using either aframed or direct bond installationmethod – ensuring that a 2-3mmgap has been left between theboard abutments.

2 Treating the jointsUsing a trowel or taping knife,generously apply a gypsum-basedsetting compound to the taperedarea of the board. Press Lafarge Joint Tape firmlyinto the compound to create agood bond and remove anyexcess material – fill the taperedarea of the boards with compoundand flatten down with a trowel.

3 Lay onWhen the joint filler starts to set,lay on a thickness of between 2 to5mm of Skim Plaster in 1 coat or 2 layers – minimum thickness 2mm.

4 Flatten downYou can flatten down when theplaster starts to pick up – youshould flatten down with a drytrowel to achieve a flat appearance.

Table 7.5 ApplicationsBackground Minimum thickness

front face (mm)

Wallboard 2

Baseboard 3

Plank 2

Firecheck 2

Panelplus 2

Vapourcheck wallboard 2

Vapourcheck baseboard 3

Vapourcheck Firecheck 2

Lath 3

Thermalcheck 2

Thermalcheck XP 2

Thermalcheck K 2

Vapourcheck Thermalcheck 2

Moisturecheck 2*

* Pre-treatment with a PVAC bonding agent is requiredprior to the application of the plaster finish

Other plasterboards may be used provided they conformto BS 1230 and have been so tested. If in doubt contactthe Lafarge Technical Enquiryline (01275) 377789

Table 7.6 CoverageThickness Coverage(mm) (m2 per 25 kg bag)

2 11

3 7.3

5 First trowelRepeat step 4, but this time witha wet trowel.

6 Second trowelBy repeating step 5 a qualityfinish can be achieved bytrowelling – care should be takennot to over work the plaster withthe trowel as this can lead to ahighly polished plaster finish,which can be more difficult toapply a paint finish.

Decoration

Lafarge Supreme Skim plastershould be allowed to dry outthoroughly before decoration isstarted. Paint manufacturer’sinstructions should be followed fordecorating on to new plaster.

Storage and Site Conditions

Lafarge Supreme Skim plaster has ashelf life of three months. It shouldbe stored in dry, well ventilatedconditions, ensuring adequateventilation at all times. The stockshould be rotated, using the oldestfirst.

All sacks and pallets should behandled with care to avoid tearingthe sacks.

Store on dry timber pallets. Do notstore in direct contact with concretefloors. Avoid storing on dampsubstrates.

Plastering should not be carried outat extreme temperatures (greaterthan 40ºC and less than 5ºC). Inparticular Lafarge Supreme Skimmust not be used on frozenbackgrounds.

Introduction



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Lafarge Supreme SkimPlastersLafarge Supreme Skim is a lightcoloured gypsum based finishplaster. It can be applied toplasterboard backgrounds toproduce a high quality finish.Lafarge Supreme Skim should beused on Lafarge plasterboard ivoryface.

Additional Clauses





NBS clauses



Notes:



Location …………………………………………………………………BackgroundThe background of ……… shall be clean of dust, dirt and grease, reasonablydry, and sufficiently true to allow the finished surface of the specified thicknessof plaster to meet the tolerances required.

Pre-treatmentApply PVAC bonding agent to BS 5270 in accordance with Lafarge technicalliterature. (Insert in pre-treatment required)

Finish coat plasteringLafarge Supreme Skim Plaster to BS 1191: Part 1: 1973, Class B, Types B1 and B2.Thickness ……… mm, applied in accordance with Lafarge Plasterboard’sinstructions.

Joint TapeLafarge Paper Joint Tape, width 50mm with centre crease. (Specify for finishedcoat on plasterboard)

Tolerances of finished surfacesTolerance of finished surface shall be in accordance with BS 5492: 1977,paragraph 37 Trueness of the Plastering System.

Corner and edge protectionLafarge Duo Bead

Lafarge Edging Bead

Plastering bead to be Type ……… by ……… all to BS 6452.


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MixingAdd the powder toclean water and mixit with a drill whiskor plunger until youachieve a creamyconsistency.

Treat jointsUsing a trowel ortaping knife,generously apply aSupreme Skimgypsum-based settingcompound to thetapered area of theboard. Press LafargeJoint Tape firmly intothe compound andflatten with a trowel.

Lay onLay on a thicknessof 2-5mm in one ortwo coats, minimum2mm depth.

Flatten downYou can flattendown when theplaster starts to pickup. You shouldflatten down with adry trowel toachieve a flatappearance.

First trowelRepeat stage 4, butthis time use a wettrowel. You mightfind that withLafarge SupremeSkim plaster a firsttrowel can be donelater than with othersimilar products.

Second trowelBy repeating stage 5,a quality matt orsemi-polished finishcan be achieved bytrowelling.

– You will find it setsin 11/2 - 2 hours.

1

2

3

4

5

6

Installation

Installation details on Lafargesystems are also available in theLafarge Installation Guide oronline at: www.lafargeplasterboard.co.uk


F I N I S H I N GTEXTURE

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Textured finishes may be used tocreate a wide range of decorativeeffects. Primarily specified inbathroom and kitchen environments,they may also be adopted to disguiseunevenness or cracking in olderceilings. Lafarge textured finishes areeasily applied and are formulated toallow practical on-site setting times.

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Lafarge Universal TextureLafarge Universal Texture provides atextured decorative finish to wallsand ceilings.

Composition

Lafarge Universal Texture is a vinyl-based white texture to provideexcellent pattern quality withoutshrink-back or slop.

Size

Lafarge Universal Texture is suppliedin 25 kg bags.

Fire spread

Lafarge Universal Texture is definedas Class 0 in accordance with theNational Building Regulations 1991Approved Document B1/2/3/4/5 FireSafety and Building Standards(Scotland) Regulations 1990,Regulation D2 when tested to BS 476: Part 6: 1989 and Part 7: 1987and is non-combustible when testedin accordance with BS 476: Part 4:1970 and Euroclass A1.

Application

There are many common texturepatterns in use, which can beclassified as regular, random orfeature patterns. Achieving thedesired pattern quality is largelydependent on the skill andexperience of the workman.

Installation

Typically Lafarge Universal Texture isapplied to the ivory face ofplasterboards and it isrecommended that a 2-3mm gap isleft between the plasterboards andthe following installation sequenceis carried out:

Apply Lafarge Universal Texture tothe joints and press Lafarge JointTape firmly into the texture. Takingcare to avoid trapping air bubbles,strike off flush with the plasterboardface, ensuring that the Lafarge JointTape is fully bedded. Fill screw headswith texture and allow to fully dry.

Apply Lafarge Sealertex or LafargeUniversal Sealer over the entireplasterboard surface; this will helpto equalise the porosity of thesurface and will increase theworking time of the UniversalTexture. Allow to dry fully beforeapplying a coat of Universal Texture.

Apply the Lafarge Universal Textureevenly to a small area (in bands upto about 500mm - 20” wide) with abrush or roller; then form thetexture pattern required, continueworking in small areas making sure

Introduction

Circle

Shell

Stipple

Scroll

Fan

Circle with fan

Swirl

Bark

to blend in the pattern as you movefrom one area to the next.

Form a margin at least 13mm -1/2”wide around all perimeters with a brush.

Note: in humid areas such asbathrooms and kitchens refer to paint manufacturer’s recommendations for suitable paint finishes.



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Lafarge Universal TextureMay be applied to any dryliningspecification.

Additional Clauses

Add general clauses, in Section 8, ifrequired, for:




NBS clauses




Location ……………………………………BackgroundThe background shall be clean, dry and free from dust, dirt and grease. Ifsurface other than new plasterboard is to be textured telephone Enquirylineon: 01275 377789.

Textured coatingLafarge Universal Texture coating applied in accordance with LafargePlasterboard’s instructions.

Joint tapeLafarge Paper Joint Tape

Sealer coatLafarge Sealertex or Lafarge Universal Sealer applied across whole drylinedsurface by brush/roller in one single coat to coverage recommended bymanufacturer.

OverpaintingOver paint, once the texture is completely dry, according to paintmanufacturer’s instructions. (In kitchens and bathrooms overpainting with awashable emulsion paint is recommended.)

Health and safetyAll recommendations contained in the Lafarge Plasterboard Health and SafetyData Sheet shall be followed. (See Lafarge COSHH Data Sheets; also HSE’sCONDAM data, to include disposal of waste product).

Storage of materialsThe recommendations of BS 8212: 1995, Section 5, paragraph 31must becomplied with, all materials used must be within their “Use by” date.

Site conditions and workmanshipProvide adequate, continuous ventilation to areas where texturing has beencarried out until texturing is completely dry.

Site conditions to be in accordance with BS 8212: 1995, Section 5, paragraph28-35. Texturing must not be carried out in temperatures less than 5ºC.

Workmanship to be in accordance with BS 8212: 1995, Sections 3 and 6, and BS 8000: Part 8: 1994.


Notes:



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F I N I S H I N GREADY RECKONER


Coverage information

Table 7.7 Coverage and ready reckonerProduct Pack size Approximate coverage per pack Shelf life

Fast Set 12.5 kg bag 25m2 for filling and bedding 4 months

37m2 as a bedding coat 4 months

Easy Finish 10 kg bag 25m2 for a full taping operation 4 months

47m2 as a finishing coat 4 months

Rapid Sand 22.5 kg bag 64m2 for a full taping operation 6 months


New Pure Velvet 25 kg bag 55m2 for a full taping operation 6 months


FineForm Mid-Weight 20 kg 45m2 for a full taping operation 6 months


Readymix Lite 20 kg 50m2 for a full taping operation 6 months


Universal Texture 25 kg 30-40m2 depending on pattern 6 months

Supreme Skim 25 kg 10m2 depending on thickness 3 months

Sealertex 10 litres 100-300m2 depending on water ratio 12 months

Universal Sealer 10 litres 100m2 12 months

Drywall Sealer 10 litres 100m2 one coat 12 months

70m2 two coat 12 months

Deco Joint Cement 20 kg 50m2 for a full taping operation 6 months

167m2 as finishing coat 6 months

Deco Machine 20 kg 62.5m2 for a full taping operation 6 months

168m2 as finishing coat 6 months

Predeco Joint Filler 12.5 kg 25m2 for filling and bedding 4 months

7 finishing - esi.infocms.esi.info/media/documents/lafar_drywallfinish_ml.pdf · finish for skim...

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