Lumber - Wikipedia, the free encyclopedia.pdf

5/23/2015 LumberWikipedia,thefreeencyclopedia

http://en.wikipedia.org/wiki/Lumber 1/14

Timberinstorageforlaterprocessingatasawmill

WoodcutfromVictorianEucalyptusregnans

TheharborofBellingham,Washington,filledwithlogs,1972

LumberFromWikipedia,thefreeencyclopedia

Lumber(AmericanEnglish)[1]ortimber(BritishEnglish,HibernoEnglish,NewZealandEnglish,andAustralianEnglish)[2]iswoodthathasbeenprocessedintobeamsandplanks,astageintheprocessofwoodproduction.

Lumbermaybesuppliedeitherroughsawn,orsurfacedononeormoreofitsfaces.Besidespulpwood,roughlumberistherawmaterialforfurnituremakingandotheritemsrequiringadditionalcuttingandshaping.Itisavailableinmanyspecies,usuallyhardwoods,butitisalsoreadilyavailableinsoftwoodssuchaswhitepineandredpinebecauseoftheirlowcost.[3]Finishedlumberissuppliedinstandardsizes,mostlyfortheconstructionindustry,primarilysoftwoodfromconiferousspeciesincludingpine,firandspruce(collectivelyknownasSprucepinefir),cedar,andhemlock,butalsosomehardwood,forhighgradeflooring.

Lumberismainlyusedforstructuralpurposesbuthasmanyotherusesaswell.Lumberisclassifiedashardwoodorsoftwood.

Contents

1Terminology1.1Remanufacturedlumber1.2Plasticlumber

2Conversionofwoodlogs3Dimensionallumber

3.1NorthAmericansoftwoods3.2Gradesandstandards3.3NorthAmericanhardwoods3.4Engineeredlumber3.5Variouspiecesandcuts3.6Timberpiles

4Defectsinlumber4.1Conversion4.2Defectsduetofungi4.3Naturalforces4.4Seasoning

5Durabilityandservicelife5.1Moisturecontrol5.2Controllingtermitesandotherinsects5.3Preservatives

6Timberframing



6Timberframing7Environmentaleffectsoflumber

7.1Residualwood8Seealso9References10Furtherreading11Externallinks

Terminology

IntheUnitedKingdom,Australia,andNewZealand,timberisatermusedforsawnwoodproducts,suchasfloorboards,whereasgenerallyintheUnitedStatesandCanada,itreferstostandingorfelledtrees,beforetheyaremilledintoboardsreferredtoaslumber.

"Timber"isalsousedtheretodescribesawnlumbernotlessthan5inches(127mm)initssmallestdimension.[4]Anexampleofthelatterisoftenpartiallyfinishedlumberusedintimberframeconstruction.

IntheUnitedKingdom,thewordlumberisrarelyusedinrelationtowoodandtimberisalmostuniversallyusedinitsplacelumberdoes,however,haveseveralothermeaningsintheUK,includingunusedorunwanteditems.

Remanufacturedlumber

Remanufacturedlumberreferstosecondaryortertiaryprocessing/cuttingofpreviouslymilledlumber.Thetermspecificallyreferstolumbercutforindustrialorwoodpackaginguse.Lumberiscutbyripsaworresawtocreatedimensionsthatarenotusuallyprocessedbyaprimarysawmill.

Resawingistheprocessofsplitting1inchthrough12inchhardwoodorsoftwoodlumberintotwoormorethinnerpiecesoffulllengthboards.Forexample,splittingatenfoot2x4intotwotenfoot1x4sisconsideredresawing.

Plasticlumber

Structurallumbermayalsobeproducedfromrecycledplasticandnewplasticstock,butitsintroductionhasbeenstronglyopposedbytheforestryindustry.[5]Blendingfiberglassinplasticlumberenhancesitsstrength,durability,andfireresistance.[6]Plasticfiberglassstructurallumbercanhavea"class1flamespreadratingof25orless,whentestedinaccordancewithASTMstandardE84,"whichmeansitburnsslowerthanalmostalltreatedwoodlumber.[7]

Conversionofwoodlogs

Logsareconvertedintotimberbybeingsawn,hewn,orsplit.Sawingwitharipsawisthemostcommonbecausesawingallowslogsoflowerquality,withirregulargrainandlargeknots,tobeusedandismoreeconomical.Typesofsawingare:

Plainsawn(flatsawn,throughandthrough,bastardsawn)Alogsawnthroughwithoutadjustingthe



Exampleof24.

positionofthelogandthegrainrunsacrossthewidthoftheboards.QuartersawnandriftsawnThesetermshavebeenconfusedinhistorybutgenerallymeanlumbersawnsotheannualringsarereasonablyperpendiculartothesides(notedges)ofthelumber.BoxedheartThepithremainswithinthepiecewithsomeallowanceforexposure.Heartcenterthecentercoreofalog.Freeofheartcenter(FOHC)Asidecuttimberwithoutanypith.Freeofknots(FOK)Noknotsarepresent.

Dimensionallumber

Dimensionallumberisatermusedforlumberthatiscuttostandardizedwidthanddepthspecifiedininches.Carpentersextensivelyusedimensionallumberinframingwoodenbuildings.Examplesofcommonsizesare24(pictured)(alsotwobyfourandothervariants,suchasfourbytwointheUK,Australia,NewZealand),26,and44.Thelengthofaboardisusuallyspecifiedseparatelyfromthewidthanddepth.Itisthuspossibletofind24sthatarefour,eight,ortwelvefeetinlength.IntheUnitedStatesandCanadathestandardlengthsoflumberare6feet(1.83meters),8(2.44),10(3.05),12(3.66),14(4.27),16(4.88),18(5.49),20(6.10),22(6.71),and24feet(7.32meters).Forwallframing,"stud,"or"precut"sizesareavailable,andcommonlyused.Foraneight,nine,ortenfootceilingheight,studsareavailablein9258inches(235cm),10458inches(266cm),and11658inches(296cm).Theterm"stud"isusedinconsistentlytospecifylength,though,sowheretheexactlengthmatters,onemustspecifythelengthexplicitly.

NorthAmericansoftwoods

Soliddimensionallumbertypicallyisonlyavailableuptolengthsof24ft(7.32m).Engineeredwoodproducts,manufacturedbybindingthestrands,particles,fibers,orveneersofwood,togetherwithadhesives,toformcompositematerials,offermoreflexibilityandgreaterstructuralstrengththantypicalwoodbuildingmaterials.[8]

Precutstudssaveaframeralotoftimeastheyareprecutbythemanufacturertobeusedin8,9and10ft(2.44,2.74and3.05m)ceilingapplications,whichmeanstheyhaveremovedafewinchesorcentimetresofthepiecetoallowforthesillplateandthedoubletopplatewithnoadditionalsizingnecessary.

IntheAmericas,twobys(24s,26s,28s,210s,and212s),namedfortraditionalboardthicknessininches,alongwiththe44(89mm89mm),arecommonlumbersizesusedinmodernconstruction.Theyarethebasicbuildingblocksforsuchcommonstructuresasballoonframeorplatformframehousing.Dimensionallumbermadefromsoftwoodistypicallyusedforconstruction,whilehardwoodboardsaremorecommonlyusedformakingcabinetsorfurniture.

Lumber'snominaldimensionsarelargerthantheactualstandarddimensionsoffinishedlumber.Historically,thenominaldimensionswerethesizeofthegreen(notdried),rough(unfinished)boardsthateventuallybecamesmallerfinishedlumberthroughdryingandplaning(tosmooththewood).Today,the



standardsspecifythefinalfinisheddimensionsandthemillcutsthelogstowhateversizeitneedstoachievethosefinaldimensions.Typically,thatroughcutissmallerthanthenominaldimensionsbecausemoderntechnologymakesitpossibleanditusesthelogsmoreefficiently.Forexample,a"2x4"boardhistoricallystartedoutasagreen,roughboardactually2by4inches(51mm102mm).Afterdryingandplaning,itwouldbesmaller,byanonstandardamount.Today,a"2x4"boardstartsoutassomethingsmallerthan2inchesby4inchesandnotspecifiedbystandards,andafterdryingandplaningisreliably112by312inches(38mm89mm).

NorthAmericanSoftwoodDimensionalLumberSizesNominal

(inches) ActualNominal

(inches) ActualNominal

(inches) Actual

1234112in(19

38mm)22 1

12112in(3838mm)

44 312312in(89

89mm)

1334212in(19

64mm)23 1

12212in(3864mm)

46 312512in(89

140mm)

1434312in(19

89mm)24 1

12312in(3889mm)

48 312714in(89

184mm)

1634512in(19

140mm)26 1

12512in(38140mm)

66 512512in(140

140mm)

1834714in(19

184mm)28 1

12714in(38184mm)

88 714714in(184

184mm)

11034914in(19

235mm)210 1

12914in(38235mm)

112341114in(19

286mm)212 1

121114in(38286mm)

Earlystandardscalledforgreenroughlumbertobeoffullnominaldimensionwhendry.However,thedimensionshavediminishedovertime.In1910,atypicalfinished1inch(25mm)boardwas1316in(21mm).In1928,thatwasreducedby4%,andyetagainby4%in1956.In1961,atameetinginScottsdale,Arizona,theCommitteeonGradeSimplificationandStandardizationagreedtowhatisnowthecurrentU.S.standard:inpart,thedressedsizeofa1inch(nominal)boardwasfixedat34inchwhilethe

dressedsizeof2inch(nominal)lumberwasreducedfrom158inchtothecurrent112inch.[9]

Dimensionallumberisavailableingreen,unfinishedstate,andforthatkindoflumber,thenominaldimensionsaretheactualdimensions.

Gradesandstandards



Thelongestboardintheworld(2002)isinPolandandmeasures36.83metres(about120ft10in).Attribution:PiotrJatthePolishlanguageWikipedia

Individualpiecesoflumberexhibitawiderangeinqualityandappearancewithrespecttoknots,slopeofgrain,shakesandothernaturalcharacteristics.Therefore,theyvaryconsiderablyinstrength,utilityandvalue.

ThemovetosetnationalstandardsforlumberintheUnitedStatesbeganwithpublicationoftheAmericanLumberStandardin1924,whichsetspecificationsforlumberdimensions,grade,andmoisturecontentitalsodevelopedinspectionandaccreditationprograms.Thesestandardshavechangedovertheyearstomeetthechangingneedsofmanufacturersanddistributors,withthegoalofkeepinglumbercompetitivewithotherconstructionproducts.CurrentstandardsaresetbytheAmericanLumberStandardCommittee,appointedbytheSecretaryofCommerce.[10]

DesignvaluesformostspeciesandgradesofvisuallygradedstructuralproductsaredeterminedinaccordancewithASTMstandards,whichconsidertheeffectofstrengthreducingcharacteristics,loadduration,safetyandotherinfluencingfactors.TheapplicablestandardsarebasedonresultsoftestsconductedincooperationwiththeUSDAForestProductsLaboratory.DesignValuesforWoodConstruction,whichisasupplementtotheANSI/AF&PANationalDesignSpecificationforWoodConstruction,providestheselumberdesignvalues,whicharerecognizedbythemodelbuildingcodes.Asummaryofthesixpublisheddesignvaluesincludingbending(Fb),shearparalleltograin(Fv),compressionperpendiculartograin(Fcperp),compressionparalleltograin(Fc),tensionparalleltograin(Ft),andmodulusofelasticity(EandEmin)canbefoundinStructuralPropertiesandPerformance[11]publishedbyWoodWorks.

Canadahasgradingrulesthatmaintainastandardamongmillsmanufacturingsimilarwoodstoassurecustomersofuniformquality.Gradesstandardizethequalityoflumberatdifferentlevelsandarebasedonmoisturecontent,sizeandmanufactureatthetimeofgrading,shippingandunloadingbythebuyer.TheNationalLumberGradesAuthority(NLGA)[12]isresponsibleforwriting,interpretingandmaintainingCanadianlumbergradingrulesandstandards.TheCanadianLumberStandardsAccreditationBoard(CLSAB)[13]monitorsthequalityofCanada'slumbergradingandidentificationsystem.

AttemptstomaintainlumberqualityovertimehavebeenchallengedbyhistoricalchangesinthetimberresourcesoftheUnitedStatesfromtheslowgrowingvirginforestscommonoveracenturyagotothefastgrowingplantationsnowcommonintoday'scommercialforests.Resultingdeclinesinlumberqualityhavebeenofconcerntoboththelumberindustryandconsumersandhavecausedincreaseduseofalternativeconstructionproducts[14][15]

Machinestressratedandmachineevaluatedlumberisreadilyavailableforenduseswherehighstrengthiscritical,suchastrussrafters,laminatingstock,Ibeamsandwebjoints.Machinegradingmeasuresacharacteristicsuchasstiffnessordensitythatcorrelateswiththestructuralpropertiesofinterest,suchasbendingstrength.Theresultisamorepreciseunderstandingofthestrengthofeachpieceoflumberthanispossiblewithvisuallygradedlumber,whichallowsdesignerstousefulldesignstrengthandavoidoverbuilding.[16]



InEurope,strengthgradingofsawnsoftwoodisdoneaccordingtoEN140811/2/3/4andsortedinto9classesInincreasingstrengththeseare:C14,C16,C18,22,24,27,30,35and40[17]

C14UsedforScaffoldingorFormworkC24GeneralconstructionC30PrefabRooftrussesandwheredesignrequiressomewhatstrongerjoiststhanC24canofferC40UsuallyseeninGlulam

GradingrulesforAfricanandSouthAmericansawntimberhavebeendevelopedbyATIBT(http://www.atibt.com/)accordingtotherulesoftheSciagesAvivsTropicauxAfricains(SATA)andisbasedonclearcuttingsestablishedbythepercentageoftheclearsurface.[18]

NorthAmericanhardwoods

InNorthAmerica,sizesfordimensionallumbermadefromhardwoodsvariesfromthesizesforsoftwoods.Boardsareusuallysuppliedinrandomwidthsandlengthsofaspecifiedthickness,andsoldbytheboardfoot(144cubicinchesor2,360cubiccentimetres,112thof1cubicfootor0.028cubicmetres).Thisdoesnotapplyinallcountriesforexample,inAustraliamanyboardsaresoldtotimberyardsinpackswithacommonprofile(dimensions)butnotnecessarilyconsistingofthesamelengthboards.

NorthAmericanHardwoodDimensionalLumberSizesNominal(roughsawnsize) S1S(surfacedononeside) S2S(surfacedontwosides)

12in 38in(9.5mm) 516in(7.9mm)58in 12in(13mm) 716in(11mm)34in 58in(16mm) 916in(14mm)

1inor44in 78in(22mm) 1316in(21mm)

114inor54in 118in(29mm) 1116in(27mm)

112inor64in 138in(35mm) 1516in(33mm)

2inor84in 11316in(46mm) 134inches(44mm)

3inor124in 21316in(71mm) 234in(70mm)

4inor164in 31316in(97mm) 334in(95mm)

AlsoinNorthAmerica,hardwoodlumberiscommonlysoldina"quarter"systemwhenreferringtothickness.4/4(fourquarter)referstoa1inchthick(25mm)board,8/4(eightquarter)isa2inchthick(51mm)board,etc.This"quarter"systemisrarelyusedforsoftwoodlumberalthoughsoftwooddeckingissometimessoldas5/4,eventhoughitisactuallyoneinchthick.

Hardwoodscutforfurniturearecutinthefallandwinter,afterthesaphasstoppedrunninginthetrees.Ifhardwoodsarecutinthespringorsummerthesapruinsthenaturalcolorofthetimberanddecreasesthevalueofthetimberforfurniture.



Freshlycutlogsshowingsaprunningfrombeneathbark

Engineeredlumber

Engineeredlumberislumbercreatedbyamanufactureranddesignedforacertainstructuralpurpose.Themaincategoriesofengineeredlumberare:[19]

1. LaminatedVeneerLumber(LVL)LVLcomesin134inchthicknesseswithdepthssuchas912,1178,14,16,18,or24inches,andareoftendoubledortripledup.Theyfunctionasbeamstoprovidesupportoverlargespans,suchasremovedsupportwallsandgaragedooropenings,placeswheredimensionallumberisn'tsufficient,andalsoinareaswhereaheavyloadisbearingfromafloor,wallorroofaboveonasomewhatshortspanwheredimensionallumberisn'tpractical.Thistypeoflumbercannotbealteredbyholesornotchesanywherewithinthespanorattheends,asitcompromisestheintegrityofthebeam,butnailscanbedrivenintoitwherevernecessarytoanchorthebeamortoaddhangersforIjoistsordimensionallumberjoiststhatterminateatanLVLbeam.

2. WoodIJoistsSometimescalled"TJI","TrusJoists"or"BCI",allofwhicharebrandsofwoodIjoists,theyareusedforfloorjoistsonupperfloorsandalsoinfirstfloorconventionalfoundationconstructiononpiersasopposedtoslabfloorconstruction.Theyareengineeredforlongspansandaredoubledupinplaceswhereawallwillbealignedoverthem,andsometimestripledwhereheavyroofloadedsupportwallsareplacedabovethem.Theyconsistofatopandbottomchord/flangemadefromdimensionallumberwithawebbinginbetweenmadefromorientedstrandboard(OSB).Thewebbingcanberemoveduptocertainsizes/shapesaccordingtothemanufacturer'sorengineer'sspecifications,butforsmallholes,woodIjoistscomewith"knockouts",whichareperforated,precutareaswhereholescanbemadeeasily,typicallywithoutengineeringapproval.Whenlargeholesareneeded,theycantypicallybemadeinthewebbingonlyandonlyinthecenterthirdofthespanthetopandbottomchordscannotbecut.Sizesandshapesofthehole,andtypicallytheplacingofaholeitself,mustbeapprovedbyanengineerpriortothecuttingoftheholeandinmanyareas,asheetshowingthecalculationsmadebytheengineermustbeprovidedtothebuildinginspectionauthoritiesbeforetheholewillbeapproved.SomeIjoistsaremadewithWstylewebbinglikeatrusstoeliminatecuttingandallowductworktopassthrough.

3. FingerJointedLumberSoliddimensionallumberlengthstypicallyarelimitedtolengthsof22to24feet,butcanbemadelongerbythetechniqueof"fingerjointing"lumberbyusingsmallsolidpieces,usually18to24incheslong,andjoiningthemtogetherusingfingerjointsandgluetoproducelengthsthatcanbeupto36feetlongin26size.Fingerjointingalsoispredominantinprecutwallstuds.Itisalsoanaffordablealternativefornonstructuralhardwoodthatwillbepainted(stainingwouldleavethefingerjointsvisible).Caremustbetakenduringconstructiontoavoidnailingdirectlyintoagluedjointasstudbreakagecanoccur.

4. GlulamBeamsCreatedfrom24or26stockbygluingthefacestogethertocreatebeamssuchas412or616.Assuch,abeamactsasonelargerpieceoflumberthuseliminatingtheneedtoharvestlarger,oldertreesforthesamesizebeam.

5. ManufacturedTrussesTrussesareusedinhomeconstructionasaprefabricatedreplacementforroofraftersandceilingjoists(stickframing).Itisseenasaneasierinstallationandabettersolutionforsupportingroofsasopposedtotheuseofdimensionallumber'sstrutsandpurlinsasbracing.InthesouthernUSAandotherparts,stickframingwithdimensionallumberroofsupportisstillpredominant.Themaindrawbackoftrussesarereducedatticspace,timerequiredforengineering



andordering,andacosthigherthanthedimensionallumberneededifthesameprojectwereconventionallyframed.Theadvantagesaresignificantlyreducedlaborcosts(installationisfasterthanconventionalframing),consistency,andoverallschedulesavings.

Variouspiecesandcuts

Squareandrectangularforms:Plank,slat,batten,board,lath,strapping(typically3/4"x11/2"),cant(Apartiallysawnlogsuchassawnontwosidesorsquaredtoalargesizeandlaterresawnintolumber.Aflitchisatypeofcantwithwaneononeorbothsides).Variouspiecesarealsoknownbytheirusessuchaspost,beam,(girt),stud,rafter,joist,sillplate,wallplate.Rodforms:pole,(dowel),stick(staff,baton)

Timberpiles

IntheUnitedStates,pilingsaremainlycutfromSouthernYellowPines(SYP)andDouglasFirs(DF).TreatedpilingsareavailableinCCAretentionsof.60,.80,and2.50pcf(poundspercubicfoot)iftreatmentisrequired.

Defectsinlumber

Defectsoccurringinlumberaregroupedintothefollowingfourdivisions:

Conversion

Duringtheprocessofconvertingtimbertocommercialformthefollowingdefectsmayoccur:

1. Chipmark:thisdefectisindicatedbythemarksorsignsplacedbychipsonthefinishedsurfaceoftimber

2. Diagonalgrain:impropersawingoftimber3. Torngrain:whenasmalldepressionismadeonthefinishedsurfaceduetofallingofsometool4. Wane:presenceoforiginalroundedsurfaceinthefinishedproduct

Defectsduetofungi

Fungiattacktimberwhentheseconditionsareallpresent:

1. Thetimbermoisturecontentisabove25%onadryweightbasis2. Theenvironmentiswarmenough3. Oxygen(O2)ispresent

Woodwithlessthan25%moisture(dryweightbasis)canremainfreeofdecayforcenturies.Similarly,woodsubmergedinwatermaynotbeattackedbyfungiiftheamountofoxygenisinadequate.

Fungitimberdefects:

1. Bluestain2. Brownrot3. Dryrot4. Heartrot



5. Sapstain6. Wetrot7. Whiterot

Followingaretheinsectswhichareusuallyresponsibleforthedecayoftimber:

1. Woodboringbeetles2. Marineborers(Barneasimilis)3. Termites4. Carpenterants5. Carpenterbee

Naturalforces

Therearetwomainnaturalforcesresponsibleforcausingdefectsintimber:abnormalgrowthandruptureoftissues.Ruptureoftissueincludescracksorsplitsinthewoodcalledshakes.Ringshake,windshake,orringfailureiswhenthewoodgrainseparatesaroundthegrowthringseitherwhilestandingorduringfelling.Shakesmayreducethestrengthofatimberandtheappearancethusreducelumbergradeandmaycapturemoisturepromotingdecay.EasternHemlockisknownforhavingringshake.[20]Acheckisacrackonthesurfaceofthewoodcausedbytheoutsideofatimbershrinkingasitseasons.Checksmayextendtothepithandfollowthegrain.Likeshakes,checkscanholdwaterpromotingrot.Asplitgoesallthewaythroughatimber.Checksandsplitsoccurmorefrequentlyattheendsoflumberbecauseofthemorerapiddryingintheselocations.[20]

Seasoning

Theseasoningoflumberistypicallydoneinakilnorairdried.Defectsduetoseasoningarethenumberonecauseforsplintersandslivers.

Durabilityandservicelife

Underproperconditions,woodprovidesexcellent,lastingperformance.However,italsofacesseveralpotentialthreatstoservicelife,includingfungalactivityandinsectdamagewhichcanbeavoidedinnumerousways.Section2304.11oftheInternationalBuildingCode(IBC)addressesprotectionagainstdecayandtermites.Thissectionprovidesrequirementsfornonresidentialconstructionapplications,suchaswoodusedaboveground(e.g.,forframing,decks,stairs,etc.),aswellasotherapplications.

Therearefourrecommendedmethodstoprotectwoodframestructuresagainstdurabilityhazardsandthusprovidemaximumservicelifeforthebuilding.Allrequireproperdesignandconstruction:

1.Controlmoistureusingdesigntechniquestoavoiddecay.2.Provideeffectivecontroloftermitesandotherinsects.3.Usedurablematerialssuchaspressuretreatedornaturallydurablespeciesofwoodwhereappropriate.4.Providequalityassuranceduringdesignandconstructionandthroughoutthebuildingsservicelifeusingappropriatemaintenancepractices.

Moisturecontrol



Woodisahygroscopicmaterial,whichmeansitnaturallyabsorbsandreleaseswatertobalanceitsinternalmoisturecontentwiththesurroundingenvironment.Themoisturecontentofwoodismeasuredbytheweightofwaterasapercentageoftheovendryweightofthewoodfiber.Thekeytocontrollingdecayistocontrolmoisture.Oncedecayfungiareestablished,theminimummoisturecontentfordecaytopropagateis22to24percent,sobuildingexpertsrecommend19percentasthemaximumsafemoisturecontentforuntreatedwoodinservice.Waterbyitselfdoesnotharmthewood,butrather,woodwithconsistentlyhighmoisturecontentenablesfungalorganismstogrow.

Theprimaryobjectivewhenaddressingmoistureloadsistokeepwaterfromenteringthebuildingenvelopeinthefirstplace,andtobalancethemoisturecontentwithinthebuildingitself.Moisturecontrolbymeansofaccepteddesignandconstructiondetailsisasimpleandpracticalmethodofprotectingawoodframebuildingagainstdecay.Finally,forapplicationswithahighriskofstayingwet,designersshouldspecifydurablematerialssuchasnaturallydecayresistantspeciesorwoodthatsbeentreatedwithpreservatives.Cladding,shingles,sillplatesandexposedtimbersorglulambeamsareexamplesofpotentialapplicationsfortreatedwood.

Controllingtermitesandotherinsects

Forbuildingsintermitezones,basicprotectionpracticesaddressedincurrentbuildingcodesinclude(butarenotlimitedto)thefollowing:

Gradethebuildingsiteawayfromthefoundationtoprovideproperdrainage.

Coverexposedgroundinanycrawlspaceswith6milpolyethylenefilmandmaintainatleast12to18inchesofclearancebetweenthegroundandthebottomofframingmembersabove(12inchestobeamsorgirders,18inchestojoistsorplankflooringmembers).

Supportpostcolumnsbyconcretepierssothatthereisatleastsixinchesofclearspacebetweenthewoodandexposedearth.

Installwoodframingandsheathinginexteriorwallsatleasteightinchesaboveexposedearthlocatesidingatleastsixinchesfromthefinishedgrade.

Whereappropriateanddesired,ventilatecrawlspacesaccordingtolocalbuildingcodes.

Removebuildingmaterialscrapsfromthejobsitebeforebackfilling.Iftermitesarefound,eliminatetheirnests.

Ifallowedbylocalregulation,treatthesoilaroundthefoundationwithanapprovedtermiticidetoprovideprotectionagainstsubterraneantermites.

Preservatives

Toavoiddecayandtermiteinfestation,itisimportanttoseparateuntreatedwoodfromthegroundandothersourcesofmoisture.Theseseparationsarerequiredbymanybuildingcodesandareconsiderednecessarytomaintainwoodelementsinpermanentstructuresatasafemoisturecontentfordecayprotection.Whenitisnotpossibletoseparatewoodfromthesourcesofmoisture,designersoftenrelyonpreservativetreatedwood.[21]



Specialfastenersshouldbeusedwithtreatedlumberbecauseofthecorrosivechemicalsusedinitspreservationprocess

Woodcanbetreatedwithapreservativethatimprovesservicelifeundersevereconditionswithoutalteringitsbasiccharacteristics.Itcanalsobepressureimpregnatedwithfireretardantchemicalsthatimproveitsperformanceinafire.[22]Oneoftheearlytreatmentstofireprooflumberwhichretardfireswasdevelopedin1936byProtexolCorporationinwhichlumberisheavilytreatedwithsalt.[23]Wooddoesnotdeterioratejustbecauseitgetswet.Whenwoodbreaksdown,itisbecauseanorganismiseatingitasfood.Preservativesworkbymakingthefoodsourceinedibletotheseorganisms.Properlypreservativetreatedwoodcanhave5to10timestheservicelifeofuntreatedwood.Preservedwoodisusedmostoftenforrailroadties,utilitypoles,marinepiles,decks,fencesandotheroutdoorapplications.Varioustreatmentmethodsandtypesofchemicalsareavailable,dependingontheattributesrequiredintheparticularapplicationandthelevelofprotectionneeded.[24]

Therearetwobasicmethodsoftreating:withandwithoutpressure.Nonpressuremethodsaretheapplicationofpreservativebybrushing,sprayingordippingthepiecetobetreated.Deeper,morethoroughpenetrationisachievedbydrivingthepreservativeintothewoodcellswithpressure.Variouscombinationsofpressureandvacuumareusedtoforceadequatelevelsofchemicalintothewood.Pressuretreatingpreservativesconsistofchemicalscarriedinasolvent.Chromatedcopperarsenate(CCA),oncethemostcommonlyusedwoodpreservativeinNorthAmericabeganbeingphasedoutofmostresidentialapplicationsin2004.Replacingitareaminecopperquat(ACQ)andcopperazole(CA).

AllwoodpreservativesusedintheU.S.andCanadaareregisteredandregularlyreexaminedforsafetybytheU.S.EnvironmentalProtectionAgencyandHealthCanada'sPestManagementandRegulatoryAgency,respectively.[25]

Timberframing

Timberframingisastyleofconstructionwhichusesheavierframingelementsthanmodernstickframing,whichusesdimensionallumber.Thetimbersoriginallyweretreebolessquaredwithabroadaxeoradzeandjoinedtogetherwithjoinerywithoutnails.ModerntimberframinghasbeengrowinginpopularityintheUnitedStatessincethe1970s.[26]

Environmentaleffectsoflumber

Greenbuildingminimizestheimpactor"environmentalfootprint"ofabuilding.Woodisamajorbuildingmaterialthatisrenewableandusesthesunsenergytorenewitselfinacontinuoussustainablecycle.[27]Studiesshowmanufacturingwooduseslessenergyandresultsinlessairandwaterpollutionthansteelandconcrete.[28]However,demandforlumberisblamedfordeforestation.



Residualwood

TheconversionfromcoaltobiomasspowerisagrowingtrendintheUnitedStates.[29]

TheU.K,Uzbekistan,Kazakhstan,Australia,Fiji,Madagascar,Mongolia,Russia,Denmark,SwitzerlandandSwazilandgovernmentsallsupportanincreasedroleforenergyderivedfrombiomass,whichareorganicmaterialsavailableonarenewablebasisandincluderesiduesand/orbyproductsofthelogging,sawmillingandpapermakingprocesses.Inparticular,theyviewitasawaytolowergreenhousegasemissionsbyreducingconsumptionofoilandgaswhilesupportingthegrowthofforestry,agricultureandruraleconomies.StudiesbytheU.S.governmenthavefoundthecountryscombinedforestandagriculturelandresourceshavethepowertosustainablysupplymorethanonethirdofitscurrentpetroleumconsumption.[30]

BiomassisalreadyanimportantsourceofenergyfortheNorthAmericanforestproductsindustry.Itiscommonforcompaniestohavecogenerationfacilities,alsoknownascombinedheatandpower,whichconvertsomeofthebiomassthatresultsfromwoodandpapermanufacturingtoelectricalandthermalenergyintheformofsteam.Theelectricityisusedto,amongotherthings,drylumberandsupplyheattothedryersusedinpapermaking.

Seealso

BoardfootCubictonDeck(building)EngineeredwoodForestryHardwoodtimberproductionListofwoodsLogging

LumberjackNontimberforestproductPulpwoodRecyclingtimberTimbertreatmentWoodWoodeconomyWoodworking

References1. http://www.merriamwebster.com/dictionary/lumber2. OxfordEnglishDictionarySecondEditiononCDROM(v.4.0)OxfordUniversityPress2009.3. "SouthernPineCostEstimates"(http://patscolor.com/materials/timber/thesouthernyellowpineflooring

deckingguide/).patscolor.com.4. "ConceptualReferenceDatabaseforBuildingEnvelopeResearch"

(http://alcor.concordia.ca/~raojw/crd/concept/concept000069.html).Retrieved20080328.5. "RecyclingandDeregulation:OpportunitiesforMarketDevelopment"(http://www.volokh.com/sasha/resrec.html)

ResourceRecycling,September19966. "ASTMD610809StandardTestMethodforCompressivePropertiesofPlasticLumberandShapes"

(http://www.astm.org/COMMIT/SUBCOMMIT/D2020.htm)ASTMCommitteeD20.20onPlasticLumber7. "SAFPLANKInterlockingDeckingSystem"

(http://www.strongwell.com/PDFfiles/Safdeck%20Safplank/SAFPLANK%20SAFDECK%20Fiberglass%20Decking%20Systems%20Brochure.pdf)Strongwell.com

8. Naturally:wood(http://www.naturallywood.com/BuildandDesign/WoodApplications/EngineeredWoodProducts.aspx)



Furtherreading

Sathre,RO'Conner,J(2010).ASynthesisofResearchonWoodProductsandGreenhouseGasImpacts(http://www.forintek.ca/public/pdf/Public_Information/technical_rpt/TR19%20Complete%20Pubweb.pdf)(PDF)(2ed.).FPInnovations.ISBN9780864885463.

9. Smith,L.W.andL.W.Wood.1964.Historyofyardlumbersizestandards.USDAForestService,ForestProductLaboratory.(http://www.fpl.fs.fed.us/documnts/misc/miscpub_6409.pdf)

10. AmericanLumberStandardCommittee:History.(http://www.alsc.org/geninfo_history_mod.htm)11. WoodWorks(http://www.woodworks.org)12. NationalLumberGradesAuthority(Canada)(http://www.nlga.org/app/dynarea/view_article/1.html)13. CanadianLumberStandardsAccreditationBoard(http://www.clsab.ca/)14. NebraskaEnergyOffice.Factsheet:Minimizingtheuseoflumberproductsinresidentialconstruction.

(http://www.neo.ne.gov/home_const/factsheets/min_use_lumber.htm)15. UniversityofWashington,SchoolofForestResources.MaterialsubstitutionintheU.S.residentialconstruction

industry.(http://www.cfr.washington.edu/Research/factSheets/11CINTRAmatsubstitute.pdf)16. Naturally:wood(http://naturallywood.com/WoodProducts/WoodPerformance/GradesandQuality.aspx)17. http://www.plankrus.com/en338.html18. http://www.fordaq.com/fordaq/html/quality_africa_sata_En.htm19. "AustinEnergypagedescribingengineeredstructurallumber"

(http://www.austinenergy.com/Energy%20Efficiency/Programs/Green%20Building/Sourcebook/engineeredStructuralProducts.htm).Retrieved20060910.

20. U.S.DepartmentofAgriculture."Shake",TheEncyclopediaofWood.NewYork:SkyhorsePub.,2007.Print.21. WoodWorksDurabilityandServiceLife(http://www.woodworks.org/files/PDF/publications/wooddesign

durabilityservicelifefactsheet.pdf)22. "WoodThatFights."(http://books.google.com/books?

id=0SkDAAAAMBAJ&pg=PA59&dq=Popular+Science+The+lads+who+fly+Britain%27s+1944&hl=en&sa=X&ei=UHyfT6aEIYOs9ATwh8C1AQ&ved=0CDkQ6AEwAA#v=onepage&q&f=true)PopularSciences,March1944,p.59.

23. "LumberisMadeFireproofbySaltTreatment"PopularMechanics,April1936(http://books.google.com/books?id=lNsDAAAAMBAJ&pg=PA560&dq=Popular+Science+1936+plane+%22Popular+Mechanics%22&hl=en&ei=YQxKTqCgIeSDsgK6xpzSCA&sa=X&oi=book_result&ct=result&resnum=1&sqi=2&ved=0CCoQ6AEwAA#v=onepage&q=Popular%20Science%201936%20plane%20%22Popular%20Mechanics%22&f=true)bottomleftpg560

24. CanadianWoodCouncilAbouttreatedwood(http://www.cwc.ca/DesignWithWood/Durability/Durability%20Solutions/Durability%20by%20Treatment?Language=EN)

25. CanadianWoodCouncilAboutTreatedWood(http://www.cwc.ca/DesignWithWood/Durability/Durability%20Solutions/Durability%20by%20Treatment?Language=EN)

26. Roy,RobertL..Timberframingfortherestofus.GabriolaIsland,BC:NewSocietyPublishers,2004.6.Print.ISBN0865715084

27. CanadianWoodCouncil(http://www.cwc.ca/DesignWithWood/Sustainability/?Language=EN)28. Lippke,B.,E.Oneil,R.Harrison,K.Skog,L.Gustavsson,andR.Sathre.2011.Lifecycleimpactsofforest

managementandwoodutilizationoncarbonmitigation:knownsandunknowns.CarbonManagement2(3):303333.(http://www.corrim.org/pubs/articles/2011/FSG_Review_Carbon_Synthesis.pdf)

29. EERENews:EERENetworkNews(http://apps1.eere.energy.gov/news/enn.cfm#id_11950)30. U.S.DepartmentofAgriculture,U.S.DepartmentofEnergyBiomassasaFeedstockforaBioenergyand

BioproductsIndustry:TheTechnicalFeasibilityofaBillionTonAnnualSupply,2005ExecutiveSummary(http://feedstockreview.ornl.gov/pdf/billion_ton_vision.pdf)



LookuplumberortimberinWiktionary,thefreedictionary.

WikimediaCommonshasmediarelatedtoTimber.

Externallinks

NationalHardwoodLumberAssociation(http://www.nhla.com/)(RulesforGradingHardwoodLumberInspectorTrainingSchool)TimberDevelopmentAssociationofNSW(http://timber.net.au/)AustraliaTDA:TimberDeckingAssociation(http://www.tda.org.uk/)UKTRADA:TimberResearchAndDevelopmentAssociation(http://www.trada.co.uk/)TheForestProductsLaboratory.USmainwoodproductsresearchlab.Madison,WI(E)(http://www.fpl.fs.fed.us/)WCTE,WorldConferenceonTimberEngineering(http://www.wcte2010.org/)June2024,2010,RivadelGarda,Trentino,ItalyCanadianWoodCouncil(http://www.cwc.ca/)ForestProductsdatainCanadasince1990(http://nfdp.ccfm.org/products/national_e.php)

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