1 Description1.1 Theproductisaspray-orhand-applied,polymer-modified renderconsistingoftwocomponents,abasecoatand atopcoat,foruseonsuitablypreparedexteriorsubstrates ofbrickwork,blockworkandconcretesuitedtoreceivinga renderedfinish.

1.2 StonepackBaseCoatisusedasaprimarycoat,priorto applicationofthefinishcoat.

1.3 StonepackRenderTopCoatisacolouredcementitious renderandisavailableinastandardrangeof13colours, othercoloursbeingavailabletospecialorder.

1.4 A8-10mmthicknessofStonepackRenderBaseCoatmay betakentohaveaweightofbetween12-15kgm2.

1.5 A8-10mmthicknessofStonepackRenderTopCoatmay betakentohaveaweightofbetween12-15kgm2.

1.6 Thecomponentsaremanufacturedinbatchblending processes.Qualitycontrolisexercisedoverincomingraw materials,duringtheproductionprocessesandonthefinal products.

2 Delivery and site handling2.1 Thecomponentsaredeliveredinsealed25kgbagsorone tonnebagonpallets.

2.2 Thecomponentsmustbestoredabove5°Cindry conditions,offthegroundinacoveredstoragearea protectedfrommoistureandfrost,andusedinrotation.

2.3 Whenstoredunopened,thetopcoatwillhaveashelf-life of12monthsfromthedateofmanufacture.Thebasecoat mustbeusedwithintwomonthsofthedateshownon thebagtoallowfortherequirementsoftheChromium(VI) DirectiveforCementandTheControlofSubstances HazardoustoHealth(Amended)Regulations2004 (COSHH).

2.4 Eachbagbearsthemanufacturer’smark,batchnumber anddateofproduction.

2.5 Thecomponentsarecement-basedandcontainmineral aggregatesandotheradditives.Theymustbehandled usingroutineprecautionsforPortlandcement.

DesignData3 General3.1 StonepackRenderwillimprovetheweatherresistanceofa wallandprovideanewdecorativefinish.

3.2 Theproductissatisfactoryforexternaluseonbackgrounds oftraditional,brickwork,blockwork,andconcrete

substratespreparedandsuitedtoreceivingarendered finish.Itisessentialthatwallsaredesignedandconstructed topreventmoisturepenetrationandtheformationof condensation.

3.3 Newconstructionstoberenderedwiththeproductshould bedesignedandconstructedinaccordancewiththe relevantrecommendationsofBS5628-3:2005(in particularClause5.5onexclusionofwater),BS5262: 1991andBSEN13914-1:2005.Thedesignershould selectaconstructionappropriatetoitslocation,payingdue attentiontodesign,detailingandworkmanship(including relevantsectionsofBS8000-10:1995)andmaterialstobe used.

3.4 Theassessmentcoverstheareaofthewallabovethe damp-proofcourselevel.Theproducthasnotbeen assessedforuse:

•onwoodwoolslabs

•overtimber-frameconstruction

•overmetal-frameconstruction

•onthebacksofparapetandscreenwallsrenderedon theface

•onhorizontalsurfacesexposedtotheweathersuchas ledges,sillsandcopings

•asrenderingtochimneystacks.

3.5 Theproductmustnotbeusedonsuperficialwater-repellent substrates,onplasterorplasterpaintorcoatings.

4 Strength and stability4.1 Theproducthasadequateresistancetoimpactdamage andcracking.Whereitmaybeexposedtosevereimpact, egsomeindustrialsites,orappliedoverexisting backgroundcracks,precautionsmayberequiredtoreduce theriskofdamage.

4.2 Incommonwithtraditionalrenders,itisessentialthatthe surfacetoberenderedprovidesasoundmechanicalkey toensureasatisfactorybondbetweenthesubstrateand theproduct.

5 Weather resistance5.1 Wallstoreceiveanapplicationoftheproductmustbe designedandconstructedinrelationtolocalexposure conditionstominimisetheincidenceofrainpenetration.

5.2 Therenderwilltendtoshedwaterandreduceconsiderably theamountofwaterabsorbedbythesubstrateduringrain.

5.3 Thewatervapourresistanceofa10mmthicknessof StonepackTopCoatis0.58MNsg–1.

5.4 Whenappliedasa15mmto20mmfinishedthickness,it issuitableforexternaluseonneworexistingbuildingsin areaswherethelocalwind-drivenrainwallspellindexis lessthan75litresm2perspell.

TechnicalSpecificationProductDatasheet

6 Performance in relation to fire Therenderisclassifiedasnon-combustibleasdescribedin thenationalBuildingRegulations.

7 Maintenance and repair7.1 Conventionalrenderingtechniquesandmaterialsmay beusedtorepairdamagetotheproducts.Theadviceof Stonepackshouldbesoughtforparticularinstallations.

7.2 Damagetotheproductsshouldberepairedimmediately andrepairsshouldbecarriedoutinaccordancewiththe relevantrecommendationsofBS5262:1991andBSEN 13914-1:2005.Regularmaintenancechecksshouldbe carriedoutonarchitecturaldetailsforsheddingwaterand onexternalplumbingandfittingstopreventpenetrationof waterintotherendering.

8 Durability8.1 Theproduct,whenappliedtoasuitablypreparedsound substratewillperformsatisfactorilyforaperiodinexcessof 25years.

8.2 Theproductmaybecomediscolouredwithtime, theratedependingonthelocalenvironment.Appearance cannormallyberestoredbycleaningwithwaterand astiffbrush.Inindustrialatmosphereslight-coloured rendersshouldbeavoided.

8.3 Theproducthasadequatecolourfastnessforaperiodin excessof20yearsbutwillbediscolouredbywaterruns andcareshouldbetakentoensurethatthemeasures giveninsection7.2aretaken.

8.4 Theproductmaysufferfromalgalgrowthinasimilar mannertotraditionalexternalrenderedfinishes.

8.5 Incommonwithtraditionalrenderstheproductmaybe subjecttolimebloom.Theoccurrenceofthismaybe reducedbyproperprotectionandavoidingapplicationin adverseweatherconditions.Theeffectislessnoticeableon whiteorpalercolours.

Installation9 Site survey and preliminary work9.1 Advicetothedesignerorrenderingcontractorisavailable fromStonepack.

9.2 Apre-applicationsurveyofthepropertyiscarriedoutto determinethesuitabilityofthesubstratetoreceivethe productsandwhetherrepairstothebuildingstructureare necessarybeforeapplication.Aspecificationisprepared bythedesignerorrenderingcontractorforeachelevation indicating:

•preliminarytreatmentofthebackground

•positionofbeads

•detailingaroundwindows,doorsandateaves

•damp-proofcourselevel

•exactpositionofmovementjoints

•areaswhereflexiblesealantsmustbeused

•anyalterationstoexternalplumbing.

9.3 TestsshouldbeconductedinaccordancewithBS3921: 1985todeterminethesaltcontentofbricksubstrates. ResultsofthetestsshouldbereportedtoStonepackto enablethemtoadviseonthesuitabilityofthesubstrateto receivetherenders.

9.4 Innewbrickworkthemortarmustconformtothebrick manufacturer’srecommendations.

9.5 Allnecessaryrepairstothebuildingstructureare completedbeforeapplication.

9.6 Itisrecommendedthatexternalplumbingberemoved and,wherenecessary,alterationsmadetounderground drainagetoaccommodateitsrepositioningonthefinished faceoftheproduct.

9.7 Onexistingbuildings,purpose-madeover-sillsmaybe necessarytoextendbeyondthefinishedfaceofthe product.Sillsshouldhaveanefficientthroatordriponthe undersideandbedesignedtopreventwaterrunningonto thewallbelow,orintothejambs.Newbuildingsshould incorporatesuitablywidesills.

9.8 Incommonwithtraditionalrenders,newwallstobe renderedshouldbeleftforaslongaspossibletominimise substratemovement.

9.9 Atthetopofwalls,theproductsmustbeprotectedby anadequateoverhangorbyadequatelysealed,purpose- madeflashing.Stonepackcanadviseofsuitable specificationsforaparticularinstallation.

10 Preparation of substrate10.1 Alldamagetothesubstratefromfrostattack,saltsor corrosionmustbecarefullyrepaired.Damagedbricksor blocksmustbereplacedandanyholesorinsufficientlyfilled jointsrepaired.Looseandspallingrenderorprojecting mortarjointsshouldberemovedandunevensurfacesmust belevelledtominimisevariationsinthethicknessofthe product.

10.2TherelevantrecommendationsofBS5262:1991and BSEN13914-1:2005mustbefollowedifa satisfactorybondistobeachieved.Inparticular,the surfacetoberenderedmustprovideagoodmechanical keyandadequatesuctionandbefreefrompaint,oil,soot, lichens,mouldsandsimilargrowthoranythinglikelyto preventasatisfactorybond.

10.3Itisessentialthatthesubstratetoberenderedisclean. Thisappliestonewaswellasoldsurfaces.

10.4Whenthesubstrateconsistsofdifferentmaterialsora materialofvariablesuctiontherecommendations ofBS5262:1991,BSEN13914-1:2005andthe manufacturer’sinstructionsmustbefollowedtoensure evenqualityandappearanceoftheproduct.

TechnicalSpecificationProductDatasheet

10.5Whenapplyingtheproducttoporousorhigh-suction substrates,particularlyinwarmweather,thesurface shouldbewettedonthedaybeforetherenderingis applied.Afurthermistsprayofcleanwatermayberequired priortoapplicationoftherender.

10.6Onbackgroundsofnegligiblesuctiontheadviceof Stonepackshouldbesoughtconcerningspecial precautionsnecessarytoprovideanadequatekey.

10.7Forsurfacesthatareeitherverysmoothorveryirregular,the adviceofStonepackshouldbesought.

10.8Whereverpossible,independentscaffoldingshouldbeused toavoidtheneedtosubsequentlymake-goodputlogholes andotherbreaksinthework.

11 Mixing11.1 Thecomponentsshouldbemixedinasuitablemechanical mixer.Cleanwatershouldbeaddedatasteadyrateof approximately3to4litresper20kgbagofeither StonepackBaseCoatorStonepackTopCoatandmixing continuedforatleastfiveminutesuntilauniformmaterial, withaconsistentworkabilityisachieved.

11.2Incommonwithtraditionalrenders,slumpingofthematerial mayoccurifthemixistoowet,increasingtheriskof settlementcracksdeveloping.

12 ApplicationGeneral

12.1Applicationiscarriedoutstrictlyinaccordancewith thisdocument,theStonepackinstructionsand specifications,andtherelevantrecommendationsofBS 5262:1991andBSEN13914-1:2005.Whenconsidering theuseoftheproductforthefirsttime,Stonepackshould beconsulted.

12.2Thebasecoatisappliedtoathicknessofapproximately 7-10mm.Akeyisthenformedbyscratching,priorto applicationofthetopcoat.

12.3Thetopcoatisappliedtoathicknessofapproximately 7-10mm,toproduceanoverallminimumthicknessof 15mm.

12.4Theproductshouldnotbeappliedinrain,mist,at temperaturesabove35°Cortemperaturesbelow5°C,orif exposuretofrostislikelytooccurduringdrying.In commonwithtraditionalsand/cementrenders,theproduct mustnotbeappliedtofrostboundwalls.

12.5Insunnyweather,workshouldcommenceontheshady sideofthebuildingandbecontinuedroundfollowingthe suntopreventtherenderdryingouttoorapidly.

12.6Tominimisecolourshadevariationsandtoavoiddryline jointing,continuoussurfacesshouldbecompletedwithout abreak.Ifbreakscannotbeavoidedtheyshouldbe madewhereservicesorarchitecturalfeatures,suchas revealsorlinesofdoorsandwindows,helpmaskcold joints.Wherelong,uninterruptedrunsareplanned,bags oftheproductshouldbecheckedforbatchnumbers; bagswithdifferentbatchnumbersshouldbecheckedfor colourconsistency.

13 Curing13.1Caremustbetakentoprotecttheproductfromdryingtoo rapidlyduetoexposuretodirectsunlightordryingwind.

13.2Theproductmustbeprotectedfromrain,mistorcold(less than5°Conafallingthermometer)duringtheearlycuring period,ordryingmaybeexcessivelyprolonged.

13.3Polythenesheetingisrecommendedforcuringandshould bearrangedtohangclearofthefaceofthewallinsucha waythatisdoesnotformatunnelthroughwhichthewind couldincreasetheevaporationofwaterfromtherender. Thepolythenesheetingmustnotbeinintermittentcontact withtheproductasthiswillproduceapatchyappearance.

13.4Oncompletionoftherenderingthesurfacemustbe checkedtoensureanevencoverage,textureand consistencyofcolour.

TechnicalInvestigationsThefollowingisasummaryofthetechnicalinvestigationscarriedoutonStonepackRender.

14 Tests Testswerecarriedouttodetermine:

•impactresistance

•flexuralandcompressivestrengthofbasecoatandthe topcoat

•watervapourpermeability

•effectoffreeze/thaw

•effectofacceleratedageingonbondstrength.

15 Investigations15.1Themanufacturingprocesswasexaminedandthe rawmaterialspecifications,formulationsandqualitycontrol procedureswereestablished.

15.2Asurveyofknownusersoftheproductwasconducted.

Bibliography BS3921:1985Specificationforclaybricks

BS5262:1991Codeofpracticeforexternalrenderings

BS5628-3:2005Codeofpracticeforuseofmasonry— Materialsandcomponents,designandworkmanship

BS8000-10:1995Workmanshiponbuildingsites—Code ofpracticeforplasteringandrendering

BSEN13914-1:2005Design,preparationandapplication ofexternalrenderingandinternalplastering—External rendering.

TechnicalSpecificationProductDatasheet