Read and Interpret Construction Drawings & specifications

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Sustainable construstion module: Read and Interpret Construction Drawings & specifications

Transcript of Read and Interpret Construction Drawings & specifications

  • UnitStandard140414:Readandinterpretconstructiondrawingsand specifications.3credits Adrawingisoneofthemosteffectivetoolswecanusetocommunicatewith.It holdsnobarriersbetweenpeoplewhodonotunderstandeachotherslanguage.It isamethodusedtocommunicateandshareideaswithpeopleofdifferent culturesandnationalities.Ancientrockartdrawingsfoundincavesaroundthe worlddescribesthewayinwhichpeoplelivedinthoseyears. Explainingtoapersonhowtobuildacupboardwillbenearimpossiblewhereas adrawingwilltakebutafewminutes. Theabilitytoreadandinterpretconstructiondrawingsisofgreatvaluetoany constructionworker.Hewillbeabletoaccuratelyconstructanarchitects architecturalconceptanddesignintoarealisticbuildingstructure.Construction drawingsuseslines,words,symbols,abbreviationsandspecificationstoindicate totheconstructionteamwhatthebuildingwilllooklikeandthepurposeanduse thereof.Inthisunitstandardweaimtodescribetoyouindetailhow Constructiondrawingsarereadandinterpreted. A/Wgraphic SpecificOutcomes WewillworktowardsachievingthefollowingSpecificOutcomesinthischapter: 1 Explaintheroleofdrawingsandspecifications. 2 Identifydrawingsandsymbolsusedonaconstructiondrawing. 3 Applyinformationfromdrawingsinconstructionactivities.
  • 4 Interpretspecificationsappearingonconstructiondrawings.
  • UNIT 1EXPLAIN THE ROLE OF DRAWINGS AND SPECIFICATIONS. Bytheendofthisunityoushouldbeableto: Explaintheroleofdrawingsinrelationtoprojectspecifications,contract documentation,quantitiesandconstruction.(SO1AC1) Explaintheroleofspecificationsinrelationtoquantities,qualityofwork, contractdocumentationandpaymenttocontractors.(SO1AC2) 1. The role of drawings (SO1 AC1) Theroleofthedrawingsistoshowthegraphicaloutlayofabuildingtobe constructed.Thesedrawingsorplansconsistmainlyoflinesandsymbolsthat aredrawntoaprecisescaledmeasurementtorepresenttheactualbuilding. Buildingsarestructureswhichareplannedanddesignedbyprofessional architects,drawnbydraughtspersonsandbuiltbybuildingcontractors.There arealsomanyotherroleplayerswhowillinteractwiththedrawingsduringthe courseoftheconstruction. Something to know Ninetyninepercentofallbuildingplansaredrawnoncomputerusinga computeraideddraughtingpackage.Someofthemostcommonlyusedprograms areAllycad,AutocadandCaddie. Abuildingprojectstartswithanownerwhointendstoerectabuilding;this couldrangefromasimplehousetoashoppingmallorschoolorevenmulti storeybuildings.Buildingsarenotallofthesamedesignandsizeanditisnot commontofindtwobuildingswhichareexactlythesame.Itisonlyinsituations ofhousingestateswherewewillfindhousesthatareofthesamedesign. Buildingsaredesignedtosatisfythespecificneedsofanownerormore specificallytheclient.Thecomplexityofabuildingstructurerequiresthatafully detailedsetofdocuments,whichclearlyspellsoutacompletedetailed descriptionoftheworkthatneedstobedone. Inorderforthisbefullyunderstoodbythebuildingcontractor,thejobofthe architectwillbetospecifyeachpartorsectionoftheconstructioninfulldetail. Itwillbetotallyimpossibleforanarchitecttodescribethedesignofabuildingin words.Architectswillthereforeproducefullydetaileddrawingstogetherwitha setofspecificationsthatwillbeusedbythecontractortoerectthebuilding.
  • Letsnowtakeacloserlookatsomeoftheimportantdocumentsthatwillbe required:Thecomplexityofthedesignrequiresafullydetaileddescriptionofthe workthatneedstobedone. Thecontractdrawings:Manyofusknowtheseastheplans.Thedrawings representapictorialoverviewoftheproposedbuilding.Itconsistsoflines, symbols,dimensions,levelsandmanyothergraphicalfeaturesofthebuilding. Wewilldiscusstheroleofthedrawingsinmoredetailinalaterchapter. Thespecifications:Specificationscanmostlybedescribedasthatwhichcannot bedrawn.Thespecificationswilleitherbewrittenonthedrawingoritwillbe compiledandanadditionalsetofnotes.Specificationsmustbewrittenclearly andinsimplelanguage.Wordsordescriptions,suchas,bestqualityorhighest qualityorproperworkmanshiparecauseforconfusion.Twoofthemost commonspecificationsinclude: Generalspecificationswhichcontaintheworkmanshipandmaterials,and Projectspecificationscovertheworkmanshipandqualityofthematerialsthat areuniquetoaspecificproject.Projectspecificationswillalwaystakepreference overthegeneralspecifications. TheBillofQuantities:Thepurposeofthebillofquantitiesistolistallthe materialsandlabouroperationsnecessarytoconstructabuilding,togetherwith ameasurementofthequantitiesofmaterialsandworkinvolved.Thisdocument isusedbythecontractorstotenderforacontract.Afullypricedbillconstitutes thecontractorsoffertoundertaketheworkatthatprice.Thebillofquantitiesis drawnupbyaprofessionalquantitysurveyor. Theconditionsofthecontract:Thiswilldefinetheliabilities,responsibilitiesand powersoftheemployer,contractorandarchitect.Itwouldincludemethodsof payment,insurance,liabilityofpartiestothecontract. Thetender:Thisisasignedfinancialofferofthecontractortoconstructthe works. Thelegaldeed:Thisdocumentissignedbybothpartiesconfirmingtheir respectiveintentiontohavecontractbetweenthemasdefinedbyalltheabove documents. Allthesedocumentstogetherwillbeknownasthecontractdocuments.
  • {Importantwordsandideas} Specifications:Isadescriptionofthequalityofworkandmaterialsfora particularjob,writteninasequenceoftradespreparedtoexplainthosethings concerningaprojectwhichcannotbeshownonadrawing, Itsmainpurposewouldbetodefinetheproductstobeused,thequalityofthe work,anyperformancerequirementsandtheconditionsunderwhichtheworkis tobeexecuted. Contractdocumentation:Thecontractdocumentationisalegalcontract whichconsistsofthedrawings,thespecification,thebillofquantitiesor scheduleofprices,thegeneralconditionsofthecontractandalegaldeedwhich bindsthecontractorandtheclient. Sequenceoftrades:Theorderinwhichthevariousbuildingandservicetrades carryouttheirworkinanewbuilding.Thisistheorderinwhichthetrade sectionsoccurinabillofquantitiesorspecification. Billofquantities:Acompletelistofthematerialsandlabouroperations necessarytoconstructabuilding,togetherwithameasurementofthequantities ofmaterialsandworkinvolved.Thisdocumentformsthebasisofthecontractors tenderandeachitemispricedbythecontractorbyinsertingtherateagainst eachitemandmultiplyingitbythequantity.Afullypricedbillconstitutesthe contractorsoffertoundertaketheworkatthatprice. Quantities:Theamountsofbuildingmaterialorbuildingoperationsneededto constructabuildingwhichiswritteninthebillofquantities. Qualityofwork:Theinspectionmethodsimplementedonabuildingsiteto ensurethataproductmaintainsacceptedminimumstandardsofquality. {End} Activity1.1 1. Explain,withnodrawingsorsketches,whereyoulive. 2. Statethedifferencebetweengeneralandprojectspecifications. 3. Statethedifferencebetweenquantitiesandqualityofwork. 4. Whatismeantbycontractdocumentation?
  • 5. Whatismeantbyatenderandalegaldeed? 2.Theroleofthespecifications(SO1AC2) Thepurposeofthespecificationsistodescribeindetailthetypeofmaterialsto beused;thespecificationscomplementthedrawings.Builderswillnotbeableto whattypeandgradeofmaterialswillberequirediftherearenospecifications. Thequantityofmaterialsandqualityofworkwillallbecontainedwithinthe specifications. Quantities:Asweexplainedearliertherearenotwobuildingsthatareexactly thesame.Itstandstoreasonthatthequantityofmaterialswillthenalsodiffer. Thebuilderwillneedtoknowhowmuchmaterialshewillneedtocompletethe proposedbuildingbeforehecandohiscostingandcompletehistender.This informationiscontainedwithinthebillofquantitieswhichconsistofanitemised listallthematerialsthatwillberequiredtocompletethejob. Thequalityofwork:Thisisoneofthemainpurposesofthespecificationsand hasadirectlinktowardsthetypeofmaterialstobeused.Themethodshemay ormaynotuseinordertoconstructthebuilding.Itwillgiveacleardescription ofthematerials,example,thetypeofsandfortheconcretemustbewellgraded riversandorallthebrickjointsmustbegroutedwithmortarwithnoopenings betweenthebrickjoints. Contractdocumentation:Thesewouldincludetheconditionsofthecontractand willaddressissuesconcerningthe: Theextentoftheworktobedone Thestartandcompletiondatesofthecontract Accesstothesite Arrangementsforthestoringofmaterials Temporaryservicesonsiteintheformofwaterconnection,electricityand toilets. Thehealthandsafetyoftheworkersaswellasthegeneralpublic Thesearebutafewalthoughtherecouldbemanymoreissueswhichbe considered. Paymenttocontractors Abuildingcontractorispaidforworkcompletedandisneverpaidinadvance. Thesepaymentsareknownasinterimpayments.Inhugeprojectspaymentswill
  • bedoneonamonthlybasis,whereasinsmallerprojectspaymentsaredone duringthedifferentstagesasbuildingprogresses.Thesestageswouldbeagreed uponbythearchitectandbuilderwhenthecontractissigned.Thepaymentor certificatewillstatetheworkthatwascompletedandthematerialsthatwere used.Atypicalpaymentplanforanormalhousewouldbe: Atthecompletionofthefoundationuptofloorlevel; Thesuperstructureuptotherooflevel; Whentheroofiscompleted; Atthecompletionofthehouse Thefinalpaymentwillbewhenalldefectsarecompleted. Activity1.2 1. Whichimportantpointsmustbeconsideredintheconditionsofcontract? 2. Whatisthepurposeofthespecifications? 3. Atwhatstagesofacontractwillthebuildingcontractorbepaid?
  • UNIT 2 IDENTIFY DRAWINGS AND SYMBOLS USED ON A CONSTRUCTION DRAWING Bytheendofthisunityoushouldbeableto: Identifydrawingsintermsoftypeandapplicationforaconstruction process.(SO2AC1) Explainthekeyfunctionsofthedrawingintermsofthefinishedproduct. (SO2AC2) Identifythekeyusersofthedrawingintermsofworkresponsibility.(SO2 AC3) Interpretsymbolsandabbreviationsintermsoftheirfunctionsand meanings(SO2AC4) Interpretthelayoutintermsofthedifferentviewsshown(SO2AC5) Explainthepurposeofeachviewintermsoftheresultoftheendproduct (SO2AC6) 1 The different types of drawings and their applications. (SO2 AC1) Itwouldnotbepossibletogiveabuilderawrittendescriptionhowtoconstructa building.Theconstructionofanybuildingwouldrequireacompletesetof drawingsthatwouldshowalltheaspectsandoutlayofaproposedbuilding. Thesedrawingsarecommonlyreferredtoastheconstructiondrawings,building planorplan. Buildingsaredesignedbyprofessionalarchitectswhoemploytheservicesof draughtspersonstodrawtheworkingdrawingsforaproject.Thedraughts personmustensurethatheconveysthearchitectsdesigncorrectlyand accuratelytothebuilderandindoingsohemustensurethatheincludesallthe necessaryinformationontheplanforthesuccessfulcompletionofthebuilding. Aconstructiondrawingforasinglestoreyhousewouldconsistofthefollowing drawings: Asiteplan Aplanviewofthefloorlayout Sectionalviews Elevations Schematiclayoutofthesewageplan Details Eachofthesedrawingswouldbeaccompaniedwithalldimensions,notesand labels.Thebuildermustbeprovidedwithalltherequiredinformationto constructthehouse.Supposingthehousehasanadditionalfloorabove,thatis,a
  • doublestoreyhouse,thentherewillhavetoplansforthereinforcedconcrete floorandstaircase.Theseareplansthatarepreparedbyaprofessionalcivil engineerandwouldinclude: Asteelreinforcementlayoutplanforthefloorandstaircase Aschedulethatwouldshowthesizesandshapesofthereinforcingsteel. 2 The key functions of the drawing in terms of the finished product. (SO2 AC2) Thekeyfunctionofthedrawingsisthatitmustbeclear,easytoread.The drawingsmustconsistofsufficientplanlayouts,sectionsandelevations, togetherwithdetailsforspecialpartsoftheconstruction.Thedrawingsmustbe neatlydrawn;withalldimensions,notesandspecificationsclearlystated.It musthaveaclearindicationwhatthefinishedbuildingwilllooklike.The constructionteammustbeabletounderstandthepurposeofthebuilding.There mustbenouncertaintywhichwillconfusethebuilders.Buildingsaredesigned asfitforpurposeforitsintendeduse.Thebuildingmustbeerectedtothecorrect specificationsasdesignedbythearchitect.Changestotheoriginaldesigncan onlybeaffectedbytheownerviathearchitect.Theownerorthebuilderisnot allowedtomakeanychangeswithoutconsultingthearchitect. 3 The key users of the drawings (SO2 AC3) Beforeandduringtheconstructiontheplanswillbeusedbyvariouspeoplewho areeitherdirectlyorindirectlyinvolvedwiththeconstructionofthebuilding. Itmightbeworthmentioningatthisstagethatmanymonthswouldpass betweenthedrawingoftheplansandthebuildingbeingconstructed.Thereason forthisisthattheplanwillgothroughmanystagesbeforefinalapprovalis grantedforthebuildingtobeerected.Thisapprovalstartswiththeclientor ownerapprovingthedesignandcostofthebuildingandthentherearethemany divisionswithinthelocalauthorityapprovingtheconstructionmethods. Oncethedrawingsareapprovedandabuildingcontractorisappointed,the contractorwillthenusethedrawingstocalculateandordertherequired buildingmaterials.Copiesofthedrawingsarealsosenttocompanieswho specializeincertainpartsoftheconstruction,thesecompaniesarecalledsub contractors.Examplesofsubcontractingcompaniesareplumbing,electricaland paintingcompanies. Acopyoftheplancanalsobesenttoaroofingcompanytopreparetheroof trusses.
  • Something to know Thebuildingcontractorisalsoknownasthemaincontractor. Subcontractorsareeithernominatedbythearchitectorownerortheyare contractedbythemaincontractor. Aplumbingcompanywillsupplythenewbuildingwithitsownwatersupply; installthebathroomfitmentsandfittingsaswellasthehotwatercylinderand kitchensink.Theyalsoconstructtheundergroundsewerdrainagesystem. Anelectricalcompanywillsupplythebuildingwithelectricity,eitherbysolar panelsorcables,lightfittings,powerplugsandconnectthehotwatercylinderto thepowersupply. Thebuildingcontractorsonsiterepresentative,knownasthegeneralforeman, willfirstusetheplanstolocatetheplotorsitewherethebuildingistobe constructed,thentopreparethesitereadyforbuildingby: Settingupthetemporarysitestructures,suchas,shedsforstoring materials,office,toiletsandtemporarywatersupply. Settingupasuitablepositionfortheconcretemixer Identifyingstorageareasforbricks,sandandstone. Identifyingaccessfordeliveryvehicleswithoutdisruptingthegeneralflow ofvehiculartraffic Settingupsecurityfencingtoprotectthegeneralpublic Oncethesitehasbeencleanedtheplanswillbeusedto: Setoutthepositionofthebuilding Establishthelevelsandheightsofthebuilding Activity2.1 1. Whodrawstheworkingsdrawingsforabuildingproject? 2. Whichpartsofthebuildingmustacivilengineerpreparedrawingfor? 3. Namethreeexamplesonabuildingsitewheresubcontractorsareused. 4. Whichpartsofthedrawingwouldbeofinteresttoaplumber? 5. Whorepresentsthebuildingcontractoronabuildingsite? 6. Whatimportantpreparationsmustbeestablishedbeforetheactual constructioncommences? 4. Abbreviations and symbols (SO2 AC4)
  • Theuseofsymbolsandabbreviationsisusedtopreventovercrowdingthe drawingwithtoomanywords.Symbolsaresimplelinedrawingsorgraphicsthat wouldrepresenteitherthevarioustypesofmaterialsorfixturesandfittingsor services.Symbolsarealsoaccompaniedbyabbreviations.Thelinesthatmakes upthedrawingsarealsosymbols;witheachlinerepresentingafeatureofthe building.Abbreviationsnormallytakestheformoftheshortenedversionofthe fullword,examplesoftheseare: TheletterBonaplanwouldindicatethepositionofthebathinthe bathroom. CONCwouldbetheabbreviationforconcrete. Tables1belowshowssomeoftheabbreviationsthatarecommonlyusedon buildingplans.Acompletelistofallabbreviationsandsymbolsaregiveninthe latestSANSCodeofPracticeonBuildingDrawingPractice. Components/Material Symbol Components/Material Symbol Air brick AB Invert level IL Aluminium AL Manhole MH Asphalt ASPH Not to scale NTS Bidet BT Bitumen BIT Overall OA Brickwork BWK Pressed metal PM Cast iron CI Polyethylene PE Cleaning eye CE Rodding eye RE or AE Concrete CONC Shower 30 SH Copper COP Sink S Column COL Soil pipe SP Cover level CL Standpipe STP Damp-proof course DPC Storm water drain SWD Damp-proof membrane DPM Storm water channel SC Drawing DRG Stormwater pipe SWP Fibre cement FC Top T Galvanized steel GALVS Unplasticized polyvinyl uPVC Granolithic GRANO chloride Hardcore HC Urinal 40 U Hardwood HWD Vent or ventilation pipe VP Inspection chamber IC Wash basin WB Wash trough WT Inspection eye IE Waste pipe WP WC pan (water closet) WC TABLE 1
  • ThefollowingtablesareextractsfromSANSCodeofPracticeonBuildingDrawing whichshowssomeofthesymbolsmostcommonlyusedonconstructiondrawings. Table2belowshowshowmaterialsarerepresented. Undisturbed earth Undressed wood Earth fill Dressed wood Hardcore Common brick Stone concrete Face brick Sand plaster or screed Sheet membrane Table2 ThesymbolsinTable3areknownasgeneralgraphicalsymbols.Thatareused toshowspecificpartsonaconstructiondrawings GENERAL SYMBOLS SERVICES FIXTURES AND FITTINGS Description Symbol Description Symbol Description Symbol Centre line Drain Bath D Gully Wash-basin Datum line Diameter Hot water Water-closet pan cylinder (toilet) WW Finished floor 0,000 Storm water Shower level drain North point Water meter Kitchen sink 1:2 Ramp Direction of the the arrow must always point up the ramp Staircase Direction of the the arrow must always point up the staircase
  • Table 3 5. The layout is interpreted of the different views shown (SO2 AC5) The purpose of each view in terms of the result of the end product (SO2 AC6) Designersmustsupplythebuilderswithalltheinformationrequiredto successfullyerectandcompleteabuilding.Thisisdonebypresentingaproposed buildingintheformofagraphicallayoutwhichwillconsistofvarioustypesof drawings.Thelayoutdrawingsarealsocommonlyreferredtoastheconstruction drawingsorbuildingplan.Abuilderusesthelayoutdrawingstointerpretthe designersideaintoreality.Alldrawingsmustbefullydimensionedandlabelled withallnotesandspecifications. Thetitlepanel Eachdrawingmustconsistofatitlepanel.Thispanelissituatedatthebottom righthandcornerofthedrawingpageandcontainsasummaryofthe informationofthedrawingsonthepage.Atypicaltitlepanelforanormalhouse willreadasfollowsandassumingitsanewhouse: NewhouseforMrandMrsJohnAndrewMazibukuonerf227, CarringtonStreet,VillageGreenEstate,Kensington,Kimberley. Signed:.. Thissignifiestothebuilderwherethehouseistobeerected.Theaddresswill alsobeshownonthesiteplan.Theinformationofthedraughtspersonmustalso beincludedinthetitlepanel. Drawnby: MrsJ.B.Sitholy,Suite105,TheWaterfall, BattlefieldDrive,Kimberley. Signed. Otherinformationwouldinclude:
  • Thenorthpoint Thedatethedrawingwascompleted. Theapplicablenotesrelatingtothedrawing. Atypicaltitlepanelisshowninfigure2.1below:
  • NOTES: New house for: Mr and Mrs John Andrew Mazibuku on erf 227, Carrington Street, Village Green Estate, Kensington, Kimberley. Signed: ....................... Drawn by: Mrs J.B. Sitholy, Suite 105, The Waterfall, Battlefield Drive, Kimberley. Signed:............... Date: 15 April 2005 Figure 2.1 Atypicalsetoflayoutdrawingswillconsistof: 1. Localitydrawings:Identifiesandlocatesthesitefromatownplan. 2. Siteplan:Thesiteplanisnormallysituatedonthebottomrighthand cornerofthedrawingpage,nexttothetitleblock.Figure2.2belowshows anexampleofasiteplan.Thisisthefirstdrawingwhichthebuilder inspectsandextractsthefollowinginformationfromthesiteplan: Thepositionoftheboundarypegs; Thedimensionsofthesite; Thelocationoftheproposedbuilding; Thedimensionedpositionofthebuildingline; Thepositionoftruenorth; Theregisterednumberofthesite; Excesstothesite; Thepositionsoftheanydrains,stormwaterchannelsandsewer lines;
  • Boundary Peg Boundary Peg Back Boundary 15,00 20,00 ERF 227 2 500 Side Boundary Side Boundary Proposed new dwelling Front building line 3 000 Site access 30 metres to Brickfield Road Front Boundary Boundary Boundary Peg CARRINGTON STREET Peg Figure 2.2 3. Theplanlayoutofthebuilding:Thisisthehorizontalortopviewofthe buildingwhichalsoshowstheshapeofthebuilding.Adoublestorey buildingwillhavetwoplanlayouts.Figure2.3belowshowsatypicalplan layoutforasinglehouse.Thefollowinginformationwillbeprovided: Thedimensionofthebuildingwhichwillincludetheoverallsizeofthe building,thethicknessofthewalls,thesizesofrooms; Thedesignationsoftherooms,example,bedroom,bathroom,kitchen; Thepositionsofthedoors,windowsandopenings; Theplumbinglayoutofthebathroomandkitchen; Thefloorlevels; Thefloorfinishes,example,tiles,carpet,timber; Thepositionsofanyfixedfurniture,example,bedroomandkitchen cupboards.
  • A 11 060 270 3 500 110 3 000 110 3 800 270 270 270 ND 10F ND 10F ND 1 ND 1 BEDROOM 2 3 000 BEDROOM 1 LIVING ROOM CARPET CARPET CARPET ND 22 7 100 110 110 7 100 900 900 ND 1 110 3 450 TABLE TOP BEDROOM 3 KITCHEN 1 870 CARPET CERAMIC TILES DINING ROOM BATH 2 360 CERAMIC TILES ND 1 TILES 600 ND 10F NC10F 270 NC2F ND 10 270 600 110 A 110 110 270 2 445 1 945 3 000 2 800 270 PLAN VIEW Figure 2.3 4. Sectionalviews:Thisisaverticalsectionwhichshowsacutthrough viewwhichwouldindicatethefollowing: Thedimensionsandpositionoftheconcretefoundations; Theheightofthefoundationwall,notlessthan4brickcoursesbelow groundlevel; Thepositionofthenaturalgroundlevel(NGL); Thepositionofthedampproofcourse(DPC),minimum150mmabovethe naturalgroundlevel; Thethicknessoftheconcretefloor; Theheightoftheexternalwallsfromthefinishfloorleveltothe undersideofthewallplate; Thefinishestoappliedtothewalls; Theheightsofthedoorandwindowframes; Thepatternandpitchoftherooftruss; Theoverhangoftherooftruss; Thefasciaboardandgutter; Thedescriptionoftheroofcovering; Thedescriptionoftheceiling;
  • Allthenotesandspecificationspertainingtothesectionalview; Figure2.4showsatypicalsectionalviewthroughoneoftheeaves. ROOF CONSTRUCTION Rationally designed roof trusses Fibre cement sheeting on manufactured by approved 75 x 50 purlins at 900 centres timber roof company Pitch 22 75 half round Roof overhang 300 mm gutters 6 mm skimmed rhinoboard on 38 x 38 brandering at 400 centres 75 mm cove cornice Bedroom 1 Plaster 2 400 Bedroom 3 Plaster DPC DPC NGL 25 mm screed on 75 mm concrete NGL 600 X 200 on 250 micron damp proof membrane on well compacted clean sand filling 600 X 200 600 X 200 SECTION A-A IBR roof sheeting on 75 x 50 purlins at 900 c/c 114 x 38 All truss Wall plate members Roof pitch 114 x 38 22 100 x 75 6 mm rhino board on gutter 38 x 38 brandering at Roof top 4 courses of 400 c/c Overhang cavity wall built 75 mm cove cornice solid dia 75 plastic swan neck 19 mm Plaster dia. 75 mm Wall tie Down pipe (Tie wire) DPC 25 mm Screed Down pipe Concrete floor shoe slab Natural ground level DPM Earth undisturbed Cavity below damp proof Earth fill course filled with concrete 600 x 200 Concrete foundation
  • Figure 2.4 5. Elevations:Elevationdrawingswouldnormallyconsistoffourdrawings whichwouldshowtheoutsideviewsofthehouse.Eachviewbeing orientatedtowardsthefourpointsofacompass,asshowninfigure2.5 below,thatis,north,south,eastandwest.Thepurposeoftheelevations areasfollows: Theoutsideheightofthebuildingtoshowthefloorlevelinrelationtothe groundlevel; Theheightandshapeoftheroof; Thefasciaboard,guttersanddownpipe; Thepositionandheightsofallthedoors,windows,stepsandsills; Appliedfinishestothewalls Fibre cement sheeting Plaster Down pipe Plaster NORTH VIEW EAST VIEW Fibre cement sheeting Plaster Down Plaster pipe SOUTH VIEW WEST VIEW
  • Figure 2.5 Activity2.2 1. Statethedifferencebetweenabbreviationsandsymbols. 2. Whyareabbreviationsandsymbolssaidtobeimportantonconstruction drawings? 3. Drawneatfreehanddrawingsofthefollowingsymbols: Concrete;facebricks;hardcore. 4. Statethedifferencebetweenalocalityplanandasiteplan. 5. Whatinformationwillabuilderextractfromthesiteplan? 6. Whatisthepurposeoftheplanviewofaconstructiondrawing? 7. Whatinformationwillabuilderextractfromtheelevationdrawings? 8. TheabbreviationsDPCandDPMappearonadrawing. 8.1 Whatdotheseabbreviationsmean? 8.2 Whereonadrawingwouldtheseabbreviationsappear? 8.3 StatetheimportanceoftheDPCandDPM. 8.4 WhatistherequiredthicknessoftheDPCandDPM? 8.5 StatetheminimumheightoftheDPC.
  • UNIT 3 APPLY INFORMATION FROM DRAWINGS IN CONSTRUCTION ACTIVITIES Bytheendofthisunityoushouldbeableto: 1. Drawingsareorientatedintermsofsitelandmarksandthenorth indicator.(SO3AC1) 2. Informationisextractedfromthedrawingsintermsofthesettingout requirementsonsite.(SO3AC2). 3. Scalesareinterpretedandmeasurementsconvertedintermsofactual dimensionsrequired.(SO3AC3) 4. Dimensionsareinterpretedfromthedrawingsintermsofsite requirements.(SO3AC4) 1. Drawings are orientated in terms of site landmarks and the north indicator. (SO3 AC1) SouthAfricareceivesallofitssunlightfromthenorthandthatiswhatbrings warmthintoourhomes.Itiscompulsoryforallbuildingplanstohaveanorth indicator.Designersthereforeorientatethebuildingtosuchadegreethatmost ofthebuildingwillbenefitfromthewarmraysofthesun,asshowninfigure3.1 below.Wewillsoonbeabletoharvest(collect)andstorethisenergyanduseitto warmourhomesagainstthecoldnights.Wewillhavemoreandmorehouses fittedwithsolarheatingcellsthatwillheatourhotwatercylinders;thenew roadsignsarealsobeingequippedwithsolarpanelstosupplyenergytolightup roadsigns. Youwillbeabletofindthepositionofnorthifyoustandinapositionwithyour rightshoulderpointinginthedirectionwherethesunrises(east)andyourleft shoulderpointinginthedirectionwherethesunsets(west).Youwillthenbe facingnorth.Thiswillhowevernotbeanaccuratemethodoffindingtruenorth, butitshouldgiveyouageneralideawhichwaynorthis.Weuseacompassto findtheexactdirectionofnorth.
  • sun of the Angle H RT NO t s Ea t uth We s So Figure 3.1 Housesareorientatedtofacenorth,yetthiswillnotalwaysbepossiblein relationtothestreetwelivein.Wewouldcertainlywantkeyareaswithinour homestoenjoysunlightthroughouttheyear.Theseareasareeitherdefinedby usorweleaveittothedesignerstochoose. 2. Information is extracted from the drawings in terms of the setting out requirements on site. (SO3 AC2). Whenabuildingplanisdrawnitmustincludealltheinformationaboutthesite aswellasthesurroundingareas.Thiswillassistthebuilderinplanningthesite. Thesewouldincludeconditionsaboveaswellasbelowgroundlevel.Someofthe importantfactorswouldinclude: Thepositionsofanyundergroundcablesorstormwaterpipes; Theconditionsofthesoil Riversorstreamsflowingthroughtheproperty Thepositionsofadjacentbuildings Restrictionsplacedonthesitebythelocalauthority Largetreesonsite,or Anyotherobstaclesthatmighthamperthesettingoutandconstruction ofthebuilding. 2 Scales are interpreted and measurements converted in terms of actual dimensions required. (SO3 AC3) Wehavementionedearlierthatbeforeabuildingcanbeconstructedorbuiltit mustfirstbepresentedinaformofadrawing.Ifweconsiderthesizeofa buildingthenitwillbeimpossibletopresentthedrawingonadrawingsheet.
  • Thiscanhoweverbedoneonlyifwerepresentthesizeofthedrawingin proportiontotheactualsizeofthebuilding.Thehugefootballstadiumsthat haverecentlybeencompletedwerealldrawntoscaletofitonnormaldrawing sheets.Figure3.2belowshowthreeviewsofasportsstadium.Eachofthe 100 m 100 m stadiumswasdrawntoadifferentscalealthoughthesizeremainsthesame. 50 m 50 m 100 m 50 m Figure 3.2 Eachdrawingonadrawingsheetmusthavethescaleofthedrawingstated belowthedraw.Drawingsthatarenotdrawntoscalewillhavetheabbreviation NTSwrittenbelowthedrawing.Letstakeacloserlookatsomepopular drawingscales.Architectsanddraughtspersonsuseaspecialscalerulertodraw objectstodifferentscales,yetthenormaleverydayschoolrulercanalsoused. Figure3.3belowshowanordinaryschoolrulerbeingusedtomeasurethree differentscales. Intheruleratthetop,1millimetreonthedrawingpaperrepresenting1actual millimetreonsite. Intherulerinthemiddle,1millimetreonthedrawingpaperwillrepresent10 millimetresonsite. Intheruleratthebottom,1millimetreonthedrawingpaperwillrepresent100 millimetresonsite. 75 mm 10 mm 0 5 10 20 30 40 50 60 70 80 90 100 Using an ordinary ruler to measure full size 750 mm 100 mm 0 5 10 20 30 40 50 60 70 80 90 100 Using the same ruler to measure to scale 1:10 7 500 mm 1 000 mm 0 5 10 20 30 40 50 60 70 80 90 100 Using the same ruler to measure to scale 1:100
  • Figure 3.3 Whenadrawingwasdrawntoscale1:10itwouldindicatethatthedrawingwas drawn10timessmallerthantheoriginalsizeandthescale1:1000indicates thatthedrawingwasdrawn1000timessmaller. Forthemoreprofessionalapproachwecanusetheproperscalerulers,figure3.4 belowshowssomeexamplesofsuchrulers.Asinglescalerulercanasmuchas8 differentscalesononeruler. 1:200;1:50and1:100 11,140 metres 3,8 m 0 5m 10m 15m 20m SCALE 1:200 Each millimetre on the 1:200 scale equals 200 millimetres 3, 75 metres 1 250 mm 0 500 1m 2m 3m 4m 5m SCALE 1:50 Each millimetre on the 1:50 scale equals 50 millimetres 7 500 mm 1 550 mm 0 1m 2 3 4 5 6 7 8 9 10 SCALE 1:100 Each millimetre on the 1:100 scale equals 100 millimetres Figure 3.4 Byreversingthescale,showninfigure3.5below,wewillbeabletodrawsmall objectstolargescales: Thescale2:1indicatesthattheobjectisdrawntotwiceitsactualsize.
  • Someverysmallobjectscanbedrawntoscale5:1whichwouldindicate thattheobjectisdrawn5timeslargerthantheactualsize. 11,140 metres 3,8 m 0 5 10mm 20mm 30mm 40mm 50 SCALE 2:1 Two millimetres on the 2:1 scale equals 1 millimetres Figure 3.5 Important words and ideas Thegoldenruletoapplywhenreadingscalesare: Ifthenumberontheleftissmallerthanthenumberontheright,thenwe aredrawinglargeobjects. Ifthenumberontheleftisgreaterthanthenumberontheright,thenwe aredrawingsmallobjects. Typicalscalesthatareusedonbuildingplansare: 1:200or1:500theseareusedtodrawsiteplans; 1:100mainlyusedtodrawtheplanlayoutandelevations; 1:50isusedforsectionalviews; 1:10or1:5areusedfordetails 3 Dimensions are interpreted from the drawings in terms of site requirements. (SO3 AC4) Acompletedconstructiondrawingforabuildingplanmustconsistofallnotes anddimensionsbeforeitisissuedtothebuildingcontractor.Theplanwillalso statethatalldimensionsandlevelsbecheckedandverifiedbeforeanybuilding workcommences.Thiswouldimplythatthebuilderisrequiredtocheckthe levelsanddimensionsonsitebeforethebuildingissetout.Itwouldbewiseofa siteforemantospendtimewiththeplansandwritedownallimportant dimensions,thiswouldhelphimwhenhegetstothebuildingsitebywhichtime hewouldhaveacompletementalpictureofthebuilding.Checkingthe constructiondrawngswouldalsoeliminateanydiscrepancieswhichcouldbe clearedwiththearchitect.Someoftheimportantnoteswouldinclude:
  • Thephysicaladdressofthesite.Thisshouldbegivenatthebottomright handcornerofthedrawingsheet,seefigure2above,oratoneofthe cornersofthesiteplanwhichwouldindicatethemeasurementtothe nearestcrossroad.Theimportanceofthisisthatmanybuildingshave beenbuiltonthewrongsite. Thesizeandshapeoftheplotasstatedonthesiteplan.Thesizeofthe siteboundariesarenormallywrittenatthecornersofthesiteplan. Thedimensionsofthebuildinglinesinrelationtothesiteboundaries. Thereshouldbeatleasttwodimensionsshowingthedistanceofthe buildinglinefromthefrontboundaryandthedistancefromaside boundary. Theinternaldimensionsmustbeequaltotheoverallexternaldimensions ofthebuilding.Shouldtherebeanerrorthentheoveralldimensionswill takepreferenceoverthesumoftheinternaldimensions.Anymajor differencesmustbeclearedwiththearchitectbeforethecommencement ofanywork. Takecaretoavoidcommonerrorswhencopyingdimensionsfromaplan. Becarefulwithwriting2960insteadof2690. Activity 3: 1. Whatscalesdoyouthinkwereusedtodrawthefootballstadiums? 2. Measuretheoutsideperimeterofyourhousethenuseascale1:100to drawtheoutsideperimeterofyourhouseonasheetofpaper. 3. Whyisitimportantthatbuildingsbeorientatedtowardsthenorth? 4. Whatimportantfactorsmustbeconsideredwhencheckingthe constructiondrawings? 5. Obtainsometypicalbuildingplanstoseewhatscaleswereusedtodraw thevariousdrawings.Useascalerulertoseeifthedimensionsare correct.
  • UNIT 4 INTERPRET SPECIFICATIONS APPEARING ON CONSTRUCTION DRAWINGS Bytheendofthisunityoushouldbeableto: 1. Materialsareidentifiedintermsoforderingrequirements(SO4AC1) 2. Specificationsandnotesareexplainedintermsofworkrequirements. (SO4AC2) 1 Materials are identified in terms of ordering requirements (SO4 AC1) Thebuildingandconstructionindustryisprobablytheoneindustrywhichusesa vastassortmentofdifferenttypesofmaterialstoconstructabuilding.Thelistof buildingmaterialscouldbeendlessasnewmaterialscontinuetoenterthe market.Buildingmaterialsarealsoevolvingtowardsoldorusedmaterials beingrecycledtomakenewmaterials.Thiswholenewshiftisaimedatstopping usfromusingtheearthsnaturalresources.Ninetyninepercentofallbuilding materialsaresourcedfromthedepthsoftheearth. Duringthedesignofthebuildingthearchitectdecideswhichmaterialswillbe bestsuitedforhisdesign;hewillalsoconsidertheenvironmentwherethe buildingistobeconstructed.Ifthehouseistobebuiltclosetotheoceanthen rustproofmaterialsshouldbeused.Inareaswhereextremewindconditionsare experiencedthensmallspanrooftileswillnotbeagoodoption. Buildingmaterialsmustbeorderedwellinadvancetoensurethecontinuityof theproject.Alwayscheckwiththesupplieraboutdeliverytimeframes.Any personwithasoundknowledgeofthebuildingshouldbeabletocompilealistof therequiredbuildingmaterialsfromthebuildingplans.Thematerialsforthe plumbingandelectricalworkwillnotbeincludedasitwillbedonebyspecialist companies.Forthesakeofconveniencewewilldividethebuildinginto4phases thiswillassistyouwhenplacingtheordersforthematerials: 1. Thefoundationuptothefloorlevel; 2. Thesuperstructureuptotherooflevel; 3. Theroofstructure,includingtheceiling; 4. Finishingwork 1. Materialsrequiredforthefoundationuptothefloorlevel. Sandandstone:Thiswillbeusedwhenmixingtheconcrete.Sandand stoneissoldbymetrecube(m).
  • Cement:Thiswillbeusedwhenmixingtheconcrete.Cementissoldin50 kgpockets. Bricks:Thesewillbeusedtobuildthefoundationwallsofthehouse. Bricksaresoldinmultiplesof1000. Sand:Thesandandcementwillbemixedwithwatertomakemortarfor thefoundationbrickwork. Dampproofmembrane:Sheetmembraneisusedasunderfloordamp proofingfortheconcretefloor.Themembraneissoldin20metrerollsin widthsof1m,2m,3m,4mand6m. 2. Thesuperstructureuptotherooflevel Dampproofcourse:TheDPCwillbeplacedontopofthefoundationwalls, whenthewallsofthehousearereadytobebuilt.Dampproofcourseis soldinwidthsof110mm,220mm,340mminrollsof40m Bricks:Thesewillbeusedtobuildthewallsofthehouse.Bricksaresold inmultiplesof1000. Sand:Thesandwillbemixedwithcementandwatertomakemortarfor thebrickwork,plasterforthewallsandscreedforthefloors. Cement:Vitalmaterialforanyconstruction.Cementissoldin50kg pockets. Doorframes:Timberframesfortheexternaldoorsandpressedmetal framesfortheinternaldoorframes.Whenorderingmetalframes,leftor rightopeningmustbespecified. Windowframes:Thiswillbespecifiedonthebuildingplanview.Consult therelevantcatalogue.Onlythecatalogueneedstobespecifiedwhen orderingwindows(steelortimber). Brickreinforcement:Brickforcewillbeusedwhenbuildingthetop4 coursesofbrickwork,underthewallplate.(Refertospecificationsbelow). Brickreinforcementorbrickforceareboughtin20mrollsof3mlength andinwidthsof75mmor150mm. Cavitytiewires:Thetiewiresareusedtotiethetwoskinsofbrickwork. Therearemanydifferentshapesanddesigns.Tiewiresarecalculatedat 2,5tiespermetresquareofbrickwork. Precastconcretelintels:Thelintelswillbeplacedoverthedoorframes, windowframesandclearopenings.Lintelsareorderedinstandard lengthsfrom900mmto6.6minincrementsof300mm. Galvanisedsteelwire:Thesteelwireswillbeusedtotiedownthetimber roofstructure.Itwillbebuiltintothewallsat600mmcentresandat least600mmdeep.
  • Fibrecementwindowsills:Thesewillusedtofinishofftheinternaland externalwindowsills.Thelengthsofthesillscorrespondtothestandard steelwindowsizes(forexample,533mm,1022mm,1511mm) 3. Theroofstructureincludingtheroofceiling Sawnsoftwoodtimber:Thebestoptionistohaveaspecialisttimberroof trusscompanymanufacturethetrusses.Thisistoensurethatallthe trussesaremadetotheexactspecifications.Thecompanyissuppliedwith abuildingplan.Thetrussesmustbeorderedwellinadvance.Alltimberis orderedinmetrelengths; Wallplates:Thesewillbesecuredtothetopofthewalltoformalevel solidbasefortherooftrussesandconsistofSawnSoftwoodtimber.The wallplatetimbermustbe114mmwideby38mmthickasisorderedin standardlengthsstartingfrom2,4mor3mandin300mmincrementsup to6.6metres.Becarefulwhenorderinglonglengthsithasthepotential forwasteduetowarpingandotherdefects. Fasciaboards:Thefasciaboardswillbenailedtotheendsoftherafterto finishofftheroofstructure.Itisalsoaplacewheretheguttersarefixed. Purlinsorbattens:Thiswillbeusedtosecuretheroofcovering. Roofcovering:Thiscouldbemetalsheeting,claytilesorfibrecement sheeting; Brandering:Thesearebattensthatwillbeusedtosecuretheceiling boards; Gypsumrhinoboards:Usedforceilingboards. Covecornice:tocoverthegapbetweenthewallsandtheceiling. Guttersanddownpipes:Toleadtherainwaterawayfromthebuilding. 4Thefinishingwork Externalandinternaldoors; Timberskirtingforthefloors; Glasspanesforthewindows; Bathroomfitments;bath,washbasin,watercloset; Kitchensink; Ironmongeryandfinishing;doorlocks,toiletrollholders,towelrails, curtainrails; Cupboardsandwardrobes Paintforthewallsandceiling
  • Varnishforthedoorsandskirtings; Carpetsandtilesforthefloors; Materialsnotshownonthedrawings Partofthefinishedproduct,butnotusuallyfoundindescriptionsorshownon drawings,arethemanytypesoffastenersusedinassemblingabuilding.These would include nails, screws, bolts, roofing screws, plugs, wire, hoop iron Galvanised steel straps), brackets and connector plates, adhesives, tile grout, cementslurryorpatentproductsusedtoprovidekeyorgripbetweenconcrete andplaster. Thentherearealsotheconsumables,thesearematerialsthatwillbeusedup andthenreplaced.Consumablesandarenotshownonanycontractdocuments. Thecontractorstillmustestimatetheirquantitiesforinclusionintheestimate orbudget,andbecausetheyhavetobepurchasedaswell.Someexamplesof consumablesare: Sandingpaper,thinners,brushesthatareusedupinpaintingoperations; Drillbits,anglegrindercuttingdiscsandsawbladesuseduponthe project; Plasticspacersforwallandfloortiling; Cleaningmaterialsthatareusedforcleaningmortarsplashesoffface brickworkandtiling; Clothanddetergentsusedforgeneralcleaningoftheworks. Thequantitysurveyor,incalculatingthecostofthebuilding,usesthedrawings andspecificationstocalculatetheexactamountofmaterialsthatwillbe requiredtobuildthehouse. Thebuildingcontractoralsousesthedrawingsandspecificationstopurchasethe materials. Thedifferencebetweenthequantitysurveyorandthecontractor,wherethe materialsareconcerned,isthatthequantitysurveyorwillusetheexactamount whereasthecontractormustallowforwaste. Anexampleofthisis: Supposearoomneedstobefittedwithaskirtingboard.Theroomconsistsof fourwallseachmeasuring3metresinlength.Thequantitysurveyorsbillof quantitieswillreflectthat12metresofskirtingisrequired.Thecontractoron theotherhandmighthavetopurchase13metresofskirtingtoallowfor cuttingthejointsandfittingtheskirting.
  • 2 Specificationsandnotesareexplainedintermsofwork requirements.(SO4AC2) Specificationsandnotesareusedtocomplimentthedrawingswithinformation thatcannotbeshownonadrawing.Notesandspecificationscanalsobe combined.Letssaytheplanlayoutofaroomstatesthatthefloorofaroommust becarpeted;thiswillregardedasanote.Thespecifictype,colour,makeand fittinginstructionsofthecarpetwillthenbespecifiedinthespecifications.Other examplesofnoteswhichcanbefoundonadrawingwillinclude: Alltimberattachedtobrickworkmustbecoatedwithwoodprimer; Thewallcavitybelowthefloorlevelmustbefilledwithweakconcrete; Thesizeoftheshowertraymustbeminimum900mmx900mm; Theshowercubiclemustbefittedwithashowercurtain; Allthewallsmustbepaintedwiththreecoatsofpaint; Thetopfourcoursesofthecavitywallbelowthewallplatemustbebuilt solid; Alldimensionsandlevelsmustbecheckedandverifiedbeforethe commencementofanywork; Examplesofspecificationswillstatethetypeandgradeofmaterialsthatmust beused,example: Ifthedrawingindicatesthatahousemustbebuiltwithbricks,thenthe specificationswillstatethetypeandsometimesthecolourofthebricks.The specificationwillread; AllthewallsmustbebuiltwithNFP(nonfacingplastered)claybricks. Asaspecificationfortherooftimber,itwillstatethat; AllrooftrussesshallbeconstructedofSawnSoftwoodtimberwitha moisturecontentofnotlessthan17% Activity Lookaroundyourhouseandcompilealistofallthematerialsthatwasusedto constructthehouse;dontforgettolookinsidetheceiling.