class 1a buildings - bretts · perpendicular to the boundary) of a class 1a building within 600 mm...

Class 1aBuildingsDESIGN & CONSTRUCTION MANUAL

National Timber Development Council

MULTI-RESIDENTIALTIMBER FRAMED CONSTRUCTION

PREFACE

Thedeemedto satisfyprovisionsof the BuildingCodeofAustralia(BCA96) describethe requirementsandlimitationsfor timberframedmulti-residentialbuildings. Theseprovisionsallow timberframingin:-

All Class1 buildings

Class2 buildingsto 3 storeys

(4 storeys wheregroundstorey is concrete/masonrycarparking)

Class3 buildingsto 2 storeys.

Thismanualoutlinesthe BCArequirementsfor Class1a buildingsandassociatedClass10 buildingswithrespectto fire separationandnoisecontrolanddescribesthe materials,detailsandconstructionpracticesthat are recommendedto satisfytheserequirements.

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The information provided will enable designers,local authorities, developers and builders toachieve practical and economical solutions forMulti-Residential Timber Framed Construction(MRTFC).

A companion publication ”MRTFC Design &Construction Manual – Class 2 & 3 Buildings”describes the requirements for these buildingclassifications.

The information, opinions, advice andrecommendations contained in this publicationhave been prepared with due care. They areoffered only for the purpose of providing usefulinformation to assist those interested intechnical matters associated with thespecification and use of timber and timberproducts.

Whilst every effort has been made to ensure thatthis publication is in accordance with currenttechnology, it is not intended as an exhaustivestatement of all relevant data, and as successfuldesign and construction depends uponnumerous factors outside the scope of thispublication, the authors and publishers acceptno responsibility for errors in, or omissions from,this publication, nor for specifications or workdone or omitted to be done in reliance on thispublication.

© FWPRDC 2000

First Edition - June 2000

CONTENTS

Section 1 SCOPE 2

Section 2 ABBREVIATIONS, DEFINITIONS,TERMINOLOGY 2

Section 3 BCA REQUIREMENTS 5

Section 4 STRUCTURAL REQUIREMENTS 8

Section 5 FIRE SEPARATION 9

Section 6 SOUND CONTROL 12

Section 7 CONSTRUCTION PRACTICEANDDETAILS 14

Section 8 FIXING OF LININGS 39

3.1 Performance Provisions 53.2 Deemed to Satisfy Provisions 53.3 SeparatingWalls 63.4 ExternalWalls 73.5 Roof Lights 73.6 SmokeAlarms 7

4.1 Timber Member Design 84.2 Noggings 84.3 Notches, Cuts and Holes 8

5.1 Fire Resistance Level (FRL) 95.2 SolidTimber at Intersections 105.3 Strengthened Joints 11

6.1 Weighted Sound Reduction Index (Rw) 126.2 Wall Framing Options 13

7.1 Sub-floor SeparatingWalls 157.2 Double Stud SeparatingWalls 16

1920202122232324

7.3 Staggered Stud SeparatingWalls 26

2829

31313232

7.4 Single Stud SeparatingWalls 337.5 347.6 367.7 Boxed Gutters 38

Intersections between suspended floorsand separating wall

Bearers supported off separating wall

Non-aligned floors

Separating walls above ceilings

Intersections with internal walls

Intersection with brick veneer external wall

Non-aligned external walls

Intersection with lightweight clad external wall.

Intersections between suspended floors andseparating walls

Bearers supported off separating wall

Separating walls above ceilings

Intersection with brick veneer external wall

Non-aligned external wall

Intersection with lightweight clad external wall.

Intersection with internal walls 30

ExternalWallsPlumbing and Electrical Services

MRTFC Class 1a - Design & Construction Manual 1

2 ABBREVIATIONS, DEFINITIONS,TERMINOLOGY

Thefollowingabbreviationsanddefinitionsapplyinthe use of thismanual.

BuildingCodeofAustralia1996-Volume2,

(a) complieswith the deemedto satisfyprovisionsofthe BCAor

(b) is an alternative solutionwhichcomplieswith theperformancerequirements.

BCA

BUILDINGSOLUTION

Class1andClass10 BuildingsHousingProvisions.

A solutionwhicheither:-

SCOP

E

1TE

RMIN

OLOG

Y

2

1 SCOPE

Thismanualcontainsthe timberindustry’srecommendationsfor the designandconstructionoftimberframedClass1a attacheddwellings(duplexes,townhouses,villasetc) andassociatedClass10buildings(carportsetc). It providesinformationonmaterialsandsystemsthathave beendeveloped,aswellas detailsandbuildingpracticesthat are necessaryto satisfythe fire resistance,andsoundcontrolrequirementscontainedin the “deemedto satisfy”provisionof the BuildingCodeofAustralia(BCA96).

Theconstructiondetailsandpracticesincluded,willgenerallycover the majorityof situations. Theyshould,however be regardedas typical,withmodificationspermitted,as longas the requiredfireandsoundperformanceis maintained.

NOTE: This manual describes the requirements forClass 1a attached dwellings and associated Class10abuildings.

NOTE:Buildingswhich containseparate residentialunits above or below one another, as well as side byside or which have common space above or belowdwellings(ie. commonceilingspaces, commonsub-floor space, commercial car parking etc.) areclassified as Class 2 or 3. These are described insupporting publication “MRTFC Design andConstructionManual– Class2 and3 Buildings”.

NOTE: It is not intendedthat this manualprovide anexhaustive statement of all the methods orconstruction details appropriate for this form ofconstruction. Although the majority of systemsavailable at the time of publication have beenincluded, manufacturers will continue to developnew and alternative systems, and practices willinvariably evolve which meet either the deemed tosatisfyorperformancerequirementsof theBCA.

2 MRTFC Class 1a - Design & Construction Manual

CAULKING(FIREGRADESEALANT)

CLASS1

Class1a

Class1b

CLASS10

Class10a

Class10b

DEEMEDTO SATISFYPROVISIONS

DWELLING

FRL- FIRERESISTANCELEVEL

Firegradematerialused to fill gaps at jointsandintersectionsin fire gradeliningsto maintainthe fireresistancelevel (referalso“IntumescentSealant”).

Oneor morebuildings,whichin associationconstitute–(a) – a singledwellingbeing– a detached

house;oroneor moreattacheddwellings,eachbeingabuilding,separatedby a fire-resistingwall,includinga row house,terracehouse,town houseor villaunit;or

(b) – a boardinghouse,guesthouse,hostelorthe like witha total floorareanot exceeding300mand in whichnot morethan12 personswouldordinarilybe resident;

whichis not locatedabove or below anotherdwellingoranotherClassof buildingother thana private garage.

A non-habitablebuildingor structurebeing–

(a) – a non-habitablebuildingbeingaprivate garage,carport,shed,or the like; or

(b) – a structurebeinga fence,mast,antenna,retainingor free-standingwall, swimmingpool,orthe like.

Provisionscontainedin Section3 of the BCAwhicharedeemedto complywith the performancerequirements.

A Class1a building

Thefire resistance,expressedas a time(in minutes)thata structuralmemberor partof a buildingmustachieve withrespectto -

(a) structuraladequacy - (ie. maintainstabilityandadequateloadbearingcapacity)

(b) integrity-(ie. resistpassageof flames,smoke andhot gases)

(c) insulation- (ie. maintaina specified temperatureon the surface not exposedto fire)

andexpressedin thatorder(e.g.FRL60/60/60forseparatingwalls).

NOTE: Caulking material may also need to beflexible to allowfor movementand/orwaterproof forexternalorwetareaapplications.

NOTE:A dash,for examplein 60/ - / - , meansthere isno integrity or insulation requirement for thatmemberorpartof thebuilding

2

NOTE: Class 1a detached houses and Class 1bbuildings (small boarding houses) have no fireresistanceandsoundcontrol requirements.

.

TERM

INOL

OGY

2


FIRE-SOURCEFEATURE

FIRESTOP

FIREGRADELINING

HABITABLEROOM

INTUMESCENTSEALANT(INTUMESCENTPUTTY)

MINERALWOOL(FIRERESISTANT)

MRTFC

(a) the far boundaryof a roadadjoiningtheallotment;or

(b) a sideor rearboundaryof the allotment;or

(c) an externalwall of anotherbuildingon theallotmentwhichis not of Class10.

Firegradematerialused to closea gap or imperfectionof fit thatoccurswherea servicepassesthrougha fire-ratedelementor system.

Firegradeplasterboardor a combinationof fire gradeplasterboardand fibrecementusedto provide therequiredFRLin a separatingwall or externalwall.

A roomusedfor normaldomesticactivities,and–

(a) includesa bedroom,livingroom,loungeroom,musicroom,televisionroom,kitchen,diningroom,sewingroom,study, playroom,familyroomandsunroom;but

(b) excludesa bathroomlaundry, watercloset,pantry,walk-inwardrobe,corridor, hallway, lobby,photographicdarkroom,clothes-dryingroom,andotherspacesof a specialisednatureoccupiedneitherfrequentlynor for extendedperiods.

A fire resistantmaterialused in fire gradelinings(atjoints,penetrationsetc)whichexpandswhenexposedto fire to fill and/orsealgaps andmaintainsthe requiredfire resistancelevel.

Compressible,non-combustible,fire resistantmaterialused to fill cavitiesandmaintainthe fire resistanceorrestrictthe passageof smoke andgases.

Multi-ResidentialTimberFramedConstruction.

NOTE: The mineral wool to be used in allapplications in this manual, must be fire resistantand therefore must have a fusion temperature inexcess of 1160°C. ‘Rockwool’ type productsgenerally meet these requirements, whilst‘glasswool’productsdonot.

To maintainFRL 60/60/60 the fire resistant mineralwool must be a minimum width of 120 mm andcompressesto85%oforiginalthickness.

NON-COMBUSTIBLE

PERFORMANCEREQUIREMENTS

RESILIENTCHANNEL/MOUNT

Rw

SEPARATINGWALL(PARTYWALL)

STC(SOUNDTRANSMISSIONCLASS)

SITE

(a) appliedto a material- meansnot deemedunderAS 1530.1-

CombustibilityTests for Materials;and

(b) appliedto constructionor partof a building-meansconstructedwhollyof materialsthatare not deemed .

Requirementsin the BCAwhichstate the level ofperformancewhicha buildingsolutionmustmeet.

Proprietarysupportfor liningsdesignedto improvesoundinsulationand reducesoundtransmission.

(refer“WeightedSoundReductionIndex”)

A wall that is commonto adjoiningClass1a buildings(referFigure1 andSection3.2).

Themethodof ratingthe airbornesoundtransmissionperformanceof a wall or floor/ceilingelementprior to1999.

Thepartof the allotmentof landon whicha buildingstandsor is to be erected.

combustible

combustible

NOTE: Walls that are common to or betweenadjoining buildings other than Class 1(a), or wallsbetween a Class 1(a) building and anotherclassificationare referred to as commonwallsor firewalls (refer “MRTFC – Design & ConstructionManual– Class2 &3 Buildings”).

NOTE:Class1a buildingsmaybe on theirownseparate allotmentwithina group title, communitytitleorTorrens title subdivision(ie. where the separatingwall is on the site boundary).AlternativelyseveralClass1a buildingsmaybe on a singleallotment,witheach dwellingsoldunderBuildingUnitor Strata title.

NOTE: The acoustic ratings required by the BCA(Amendment6 - 1999) are now called the “weightedsound reduction index” with the symbol ,consistentwithAS/ NZS1276.11999.

Test results for buildingsand building elementswithSTC values in accordance with the 1979 version ofAS 1276 remain valid (the STC value being the Rwvalue).

Rw

Theratingof soundinsulationin a buildingor buildingelementas describedinAS/NZS1267.11999.

WEIGHTEDSOUNDREDUCTIONINDEX(Rw)

dwelling 1

dwelling 5

dwelling 10

dwelling 2

dwelling 6

dwelling 11

dwelling 3

dwelling 7

dwelling 12 dwelling 13

dwelling 4

dwelling 9dwelling 8

Parapets above combustible roof

Suspended floor Separating wall continueddown to ground

Attached carports or garages(class 10 a)

Private garages may be underor within class 1a dwelling

Fire rated external wallabove lower roof

Separating wall continued up tounderside of non-combustible roof

FIGURE 1 - TYPICAL CLASS 1a BUILDINGS

External walls to be fire-ratedif within 900 mm of boundary or1800 mm of another building

Fire rated external wall continued upto underside of combustible roofor non combustible eaves lining

TERM

INOL

OGY

2


BCAR

EQUI

REME

NTS3


3 BCA REQUIREMENTS

3.1 PerformanceProvisions

Structure

DampandWeatherproofing

Fire Safety

HealthandAmenity

SafeMovementandAccess

Thefollowingsummarisesthe BCA’s objectives andperformancerequirementsfor Class1 and10 buildingswithrespectto:

a) - withstandthe combinationof loadsandotheractionsto whichthey maybe reasonablysubjected.

b) – provideresistanceto moisturefromthe outsideandmoisturerisingfromthe ground.

c) – protectbuildingsfromthe spreadoffire andprovidesafeguardsso thatoccupantsmaysafelyevacuate.

d)

i) WetAreasnot to createunhealthy or dangerousconditions

ii) Roomheightsto be suitablefor the intendeduse

iii)Providefacilitiesfor personalhygiene,laundering,foodpreparationandcooking

iv) Provideadequatenaturalandartificial light

v) Provideadequateventilation

vi) Prevent unduesoundtransmissionbetweendwellings.

e)

i) Providesafeaccessto andwithinthe building

ii) Restrictaccess(youngchildren)to swimmingpools.

A buildingsolutionmustsatisfyall of the performanceprovisionsof the BCA. Thebuildingmayeithersatisfythe “deemedto satisfy”provisionsof the BCA(andasdescribedin the manual)or be an “alternative solution”whichcan be shown to satisfythe performanceprovisions.

NOTE: For guidance on gaining approval for analternative solution using the performanceprovisions of the BCA refer to MRTFC InformationBulletinNo.2.

3.2 Deemedto SatisfyProvisions

fire separationbetweendwellings

soundcontrol betweendwellings

TheBCAcontains“deemedto satisfyprovisions”thatare acceptableformsof constructionwhichcomplywith the performancerequirements.Thesimplestwayto obtainapproval or certificationfor a projectis tocomplywith the deemedto satisfyprovisions.

For attachedClass1a MRTFCprojectsthe majorityofthe deemedto satisfyrequirements(as wellas theperformanceprovisions)are the sameas therequirementsfor detachedhouses. The requirementsare the samefor:-

• structuraldesign(useAS 1684-1999‘ResidentialTimberFramedConstruction)

• dampandweatherproofing

• kitchensand wetareas

• roomsizesandheights

• lightandventilation

• safeaccess.

TheBCArequirementsfor attacheddwellingswhichare in additionto or differentfromthosefor detacheddwellingsare:-

(a) - separatingwalls mustbe of fire resistingconstruction.Externalwalls mustalsobe fire resistingif closeto aboundaryor anotherbuilding.

(b) - separatingwalls must reducesoundtransmission(noise).

NOTE:Thismanualcontainstimberframedsystems,construction details and building practices whichsatisfy the “deemed to satisfy” fire separation andsoundcontrol requirementsof theBCA.

BCA R

EQUI

REME

NTS3

3.3 SeparatingWalls

To satisfythe BCAdeemedto satisfyfire andsoundrequirements,separatingwalls betweenClass1adwellingsshall:-

(a) be continuousfromfooting(or concreteslabonground)to undersideof non-combustibleroofcoveringor 450mmabove combustibleroof.(refer Figure1).

(b) have a fire resistancelevel not less thanFRL60/60/60(-/60/60if non-loadbearing)(referSection5.1)

(c) not be crossedby timbermembers(or othercombustiblebuildingelements)other thanroofbattens(maximumsize75 x 50 mm).

(d) have any void betweentop of wall andundersideofroofing (ie. betweenbattens)filledwithsolidtimber, fire resistantmineralwool or othersuitablefire resistingmaterial.

(e) extendthroughto the outsideof externalwalls(ie. have cavities in brickveneerexternalwallspacked withfire resistantmineralwool, solidtimberblockingor othersuitablefire resistingmaterial- (referFigure16).

NOTE: All intersectionsmust be constructedso thatin the event of fire, floors, ceilings, roof, internalwalls etc (within the dwelling on fire) are able tocollapsebut leavetheseparatingwallintact.

NOTE: Cavities to be maximum 50 mm width.flashing, dpc etc to be provided to maintainweatherproofingwhere cavitiesare packed.

NOTE: The above BCA sound requirements shouldbe regarded as minimum regulatory standards.Higher levels of sound resistance are recommendedtosatisfyconsumerexpectations.

(f) extendthroughto the outsideof andeffectivelyseparatevoids in boxed eaves etc (referFigure30).

(g) have a soundtransmissionclassof not less than:-

i) Rw 45 betweenhabitableroomsin adjoiningdwellings.

ii) Rw 45 betweenkitchensor wetareas inadjoiningdwellings.

iii)Rw 50 (as wellas resistanceto impactsound)betweena kitchen,bathroom,WCor laundryinonedwellinganda habitableroomin anadjoiningdwelling.

Boundary

dwelling 1

dwelling 2 dwelling 3

dwelling 4

Walls within 1800 mm of anotherbuilding to have FRL 60/60/60

The portion of thewall within 900 mmof boundary FRL60/60/60

Wall within 900 mm ofboundary measured atright angles to have FRL 60/60/60

Note:These portions of wall notrequired to be fire rated becausethey are greater than 900 mmfrom boundary and greater than1800 mm from other buildingsmeasured at right angles

Note: These walls not requiredto be fire rated because they aregreater than 900 mm fromboundary and greater than1800 mm from other buildingsmeasured at right angles

1800 mm

900mm

900mm

FIGURE 2 - FIRE RESISTING EXTERNAL WALLS


3.4 ExternalWalls

In all statesexceptSouthAustralia,externalwalls inClass1a buildingsare requiredto be fire-resistingifless than900mmfromrearor sideboundariesor lessthan1800mmfromanotherbuilding.Theclearancesare measuredat rightangles(90°) to eithertheboundaryor the externalwall of anotherbuilding(referFigure2).

Fire resistingexternalwalls musthave a fire resistancelevel not less thanFRL60/60/60whenmeasuredfromthe outside.( - /60/60if non-loadbearing).

Fire resistingexternalwalls mustextendto theundersideof a non-combustibleroofcoveringor to anon-combustibleeaves lining(referFigure27).

Openings(doors,windows etc) in fire resistingexternalwalls mustbe protected.

The followingare regardedas beingprotected:-

(a) self closingsolidcoredoors

(b)non-openablefire windows (FRL- /60/ -) tohabitablerooms.

(c) maximum900x 600mmwindows withsteel frameandno openingsashesto non-habitablerooms.(Note: Canbe permanentlyvented).

(d)Translucenthollow glassblocks.

NOTE: State and Local authorities throughoutAustralia may have planning regulations whichcontaindifferentsitingrequirements.

TheSouthAustralianHousingCoderequires: -

External walls (including those at an angle orperpendicular to the boundary) of a Class 1abuilding within 600 mm of the allotment boundary,or within 1200 mm of another building on the sameallotment, shall be of fire-resisting construction tothe underside of non-combustibleroof liningor non-combustible eaves lining to resist the spread of firefrom the outsideexcept where protectedby a wall offire-resistingconstruction(e.g. a ‘wingwall’).

NOTE: Fire rated external walls in Class 1abuildings do not require fire resistance from theinside.

NOTE: Eaves soffit lining must be non-combustiblebut it is not required to be fire rated or have a fireresistance level. Normal fibre cement products areacceptable.

3.5 RoofLights

3.6 SmokeAlarms

Rooflights,(skylightsetc)whichcontaincombustiblematerial,maybe installedin a roofwhichis requiredtohave a non-combustiblecoveringprovided:-

(a) the areaof the roof light is not morethan20%of theroofarea

(b)the roof light is not less than900mmfromtheallotmentboundary

(c) the roof light is not less than900mmfromtheverticalprojectionof any separatingwall whichextendsto the undersideof the roofcovering

(d)the roof light is not less than1.8 m fromany rooflight in anotherbuildingon the allotment.

TheBCArequiresthat all Class1a buildingshaveautomaticsmoke alarmsinstalled.

Smoke alarmsmustcomplywithAS 3786andbeconnectedto mainspower.

Alarmsshallbe installedon or near the ceiling(at leastonealarmper storey), locatedbetweeneachpartof thedwellingcontainingbedroomsand the remainderof thedwelling.

NOTE: Where any of these limitationsare exceeded,the roof covering is regarded as combustible.Separating walls would therefore be required toproject450mmabove theroof.

NOTE: The intention of smoke alarms is to detectsmoke before it reaches sleeping occupants, wakethem,andgivethemtimetoevacuatetosafety.

BCAR

EQUI

REME

NTS3


4 STRUCTURAL REQUIREMENTS

4.1 TimberMemberDesign

4.2 Noggings

4.3 Notches,Cuts,Holes

Timbermembersizesfor Class1(a)buildingsshallbedeterminedin accordancewithAS 1684-1999ResidentialTimberFramedConstruction.

In separatingwalls and fire ratedexternalwalls thestudsandplatesshallalsobe the sizedeterminedfromAS 1684.Theminimumsizeof studsshallbe 70 x 45mmor 90 x 35 mmstudsin loadbearingseparatingwalls.70 x 35 mmstudscan onlybe usedin non-loadbearingseparatingwalls.

Thestudspacingin separatingwalls and fire ratedexternalwalls shallnot be greaterthan600mm.

Timberspeciesshallhave an averagedry densityof notless than450kg/m .

(Note: Normalsoftwood,cypressandhardwoodframingmaterialmeetsthis requirement).

Noggingsshallbe providedin all loadbearingwalls at amaximumspacingof 1350mm.Noggingsmaybestaggered(by up to the noggingdepth).

Wherever possible,notches,cutsandholesshouldbeavoidedin structuralmemberswithinfire ratedwalls.Wherethesecannotbe avoided,sizesandspacingsshallbe limitedto thoseinAS 1684 - 1999.

3

NOTE: To achieve satisfactorysound performancein double stud and staggered stud walls, noggingsbetween studs supporting linings to one dwellingmust be kept clear of studs and nogging supportingthe linings to the adjoiningdwelling(refer Figures 9and19).

STRU

CTUR

ALRE

QUIR

EMEN

TS

4

Stud

Stud depth

(D)

Bottom plate

E

E

F

A

A

B

Stud width

(W)

C

P

FIGURE 3 - CUTS, NOTCHES AND HOLES.

TABLE A CUTS, HOLES AND NOTCHES IN STUDS ANDPLATES

DESCRIPTION LIMITS

A Distance between holesand/or notches in studbreadth Minimum 3 x D

H Hole (studs and plates) Maximum 25 mm inwide face only

C Notch into stud breadth Maximum 10 mm

E Notch into stud depth • Maximum 20 mm atevery fifth stud

• Maximum 20 mm fordiagonal bracing

• Up to 25 mm forinstallation of bath

• Not permitted where studsare designed as “notnotched”

F Distance betweennotches in stud depth Minimum 12 x B

P Trenches in plates 3 mm maximum


FIRES

EPER

ATION

5

5 FIRE SEPARATION

5.1 Fire ResistanceLevel

Separationwalls betweenClass1 attacheddwellings,mustbe constructedto limit the spreadof fire andallowthe occupantsto safelyevacuate. The level of fireresistancerequiredby the BCAis for the separatingwall to remainstructurallyintactandnot allow thepassageof flame,heat, smoke andhot gases for aperiodof at least1 hour. This fire resistancelevel isexpressedas FRL60/60/60(or FRL- /60/60for non-loadbearing).

WhereClass1 buildingsare within900 mmof a sideorrearboundary, or closerthan1800mmto anotherbuilding(In SouthAustralia,within600mmofboundaryor within1200mmof anotherbuilding),externalwalls also requirea fire resistancelevel ofFRL60/60/60(or - /60/60for non-loadbearing). TheFRLfor an externalwall onlyrequiresto be measuredfromthe outside.

To achieve the fire resistancelevel in timberframedwalls, fire gradeliningsare fixed to studswithalljoints, intersectionsandpenetrationssealed.

Liningmanufacturers(in associationwith the timberindustry)have developedvarioussystemswhichhavebeentestedandcertified by recognisedtestingauthorities(CSIRO or BRANZ). FRL60/60/60separatingwalls have eithera singlelayerof 16 mmthickfire gradeplasterboardeachside,or a layerof 13mmfire gradeplasterboardplusa layerof 6 mmfibrecementto bothsides. (Manufacturer’srecommendationsfor fixingsheetsmustbe strictlyadheredto).

To ensurethe fire resistanceis maintainedat joints,intersectionsandpenetrations,the variousbuildingpracticesanddetailscontainedin thispublicationshouldbe followed(referSection7).


FIRE S

EPER

ATION

5


5.2 SolidTimberat Intersections

Many of the constructiondetailsin thismanualincorporateadditionalsolid timber(blockingor extrastuds, joists,etc.) in lieuof the fire gradeliningtoprotectthe timberframeandmaintainthe fireresistancelevel at intersectionsetc. Thissystemhasbeendevelopedto simplifyandspeedup theconstructionprocessby allowingall framingto becompletedand roof installedbeforefixingplasterboardlinings.

NOTE: Whentimberburns,it chars relativelyslowlyfrom the outside at a predictable rate. This allowsadditional,sacrificial timberto be used in lieu of firegradelining, toprotectstructuralmembers.

To maintainFRL60/60/60at intersectionsa minimumof 45 mmthicknessof solid timber(minimumaveragedry densityof 450kg/m ) is required. This is inadditionto any structuralmemberwithinthe fire ratedwall.

Figure4 shows typicaljunctionswhere45 mmthicknesssolid timberis used in lieuof fire gradelining.

3

NOTE: The timber used to maintain the FRL cannotcarry out a structural function within the separatingwall. It can however be used to support non-ratedfloors or partitions. No additional fixing is required(for ledgers etc.) other than required to support loads.

NOTE: Any timber grade and species (hardwood,softwood, LVL) commonly used for framing has anaverage drydensityin excessof 450kg/m andcanbeusedforblocking.

3

FIGURE 4 - TYPICAL JUNCTIONS WITH ADDITIONAL SOLID TIMBER

1 x 45 or 2 x 35 mm studs tomaintain fire resistance where

fire grade linings do notcontinue through intersection

Fire grade linings

Non-rated partition

Non-rated timber floor

Fire grade linings

Separating walls(double studs or staggered studs)

Separating walls(double studs or staggered studs)

Additional 45 mm thick joist, ledger, trimmeror blocking to maintain fire resistance

Nogging tosupport edgeof lining Joist/bearer to support upper wall

4(a) - Typical intersections between separating wall and internal partition

4(b) - Typical intersections between separating wall and timber floor

Caulking

FIRES

EPER

ATION

5

35 mm x 35 mm plasterers’ angle

Intumescent sealant

Fire grade plasterboard

Fibre cement lining continuousthrough intersection

Studs positioned tosupport angles

Studs behind sealant

Noggings or topplate to supportedge of lining

Noggings on top plate

Noggings at 600 mmmaximum centres if studsare not at intersection

5(a) - Using 35 x 35 mm Plasterer’s angles

5(b) - Using intumescent sealant

5(c) - Using continuous fibre cement lining


5.3 StrengthenedJoints

Wherethe intersectionbetweenthe fire gradeliningsisstrengthenedby either:-

• 35 x 35 mmplasterer’s angle

• intumescentsealeror

• fibrecementliningcontinuedthroughjoint

Thenthe thicknessof solid timberto maintainFRL60/60/60can be reducedto 35 mm. Figure5shows typicalintersectionswhichhave beenstrengthenedandallow the use the reducedtimberthickness.

FIGURE 5 - STRENGTHENED JOINTS

Caulking

Caulking

SOUN

DCO

NTRO

L

6

6 SOUND CONTROL

6.1 WeightedSoundReductionIndex(Rw)

TheBCArequiresthe weightedSoundReductionIndex (Rw)and the resistanceto impactin separatingwalls as shown in TableB.

TABLE B BCA REQUIREMENTSRw AND SOUND IMPACT LEVELS FORSEPARATING WALLS

NOTE: The BCA requirements for sound controlbetween dwellings listed above should only beregarded as the absoluteminimumto meet statutoryrequirements. It is recommendedthat a minimumofRw50 be providedandresistanceto impactsoundbeconsidered in all separating walls. Rw 50 withimpact resistance is considered necessaryto reduceairborneand structure borne noise to an acceptablelevel.

Test results for buildings or building elements withSTC values in accordance with the 1979 version ofAS 1276 remain valid.The STC value is the same astheRwvalue.

COMMENTARY:

Thereare two typesof soundswhichneedto becontrolled. Theseare fromairbornesourcessuchas speech,musicalinstrumentsand loudspeakersand the otherbeingimpactsources,suchasfootstepsand the movingof furniture.

Soundtransmissioncan be reducedby:-

Increasingmasscan be achieved byincreasingliningthicknessor densityor usingmorelayersof linings.

Oneof the mosteffective ways of reducingsoundtransmission(airborneand impact)isto isolatethe wall surfacesof adjoiningdwellings. This is achieved throughthe use ofdoublestudor staggeredstudwall.

Fillingthe cavitywithabsorptive insulationmaterial(cellulosefibre,glassfibreormineralwool)can reduceairbornetransmissionsubstantially, especiallywhenthe cavity is large.

Soundleakscan easilyoccurat the peripheryof walls and floors,or wherea hole is madefor electricityor plumbingservices. Toreducesoundleaks,all gaps in a wall or floormustbe thoroughlycaulked, or sealed.

Oneof the simplestmeansof controllingnoiseis to distancenoisesourcesfromsensitive receivingareas. Laundries,serviceshafts,stairsandothernoisyareas inbuildingsshouldbe locatedas far as possiblefromsensitive livingor sleepingareas.Placingrelatively quietareassuchasbedroomsor loungeroomsnext to eachotheralsohelpsto minimisethe noisereductionrequiredfor occupantsatisfaction. Care isrequiredin locatingthe windows to ensurethey do not face noisyareasand that there isadequateseparationbetweenwindows inadjoiningdwellings.

• IncreasingMass

• UsingCavityConstruction(Isolatingwallsurfaces)

• UsingAbsorptive Material

• Sealing/CaulkingVoids

• BuildingLayout

• AvoidingRigidConnections

Rigidconnectionsbetweenadjoiningdwellingscan transmitsoundenergy. Whereconnectionsare requiredfor structurestabilityetc., resislientconnectorsshouldbeused.


LOCATION IMPACT RwSOUND LEVEL

RESISTANCE

SEPARATING WALLS

SOIL AND WASTE PIPES

(a) Between a bathroom,sanitary compartment,laundry or kitchen in one Required 50Class 1 building and ahabitable room (other thana kitchen) in an adjoiningClass 1 building.

(b) All other separating walls. Not Required 45

A waste pipe or otherpenetration that serves orpasses through a separatingwall between houses –(a) If the adjacent room is a

habitable room (other thana kitchen); or Not Required 45

(b) if the room is a kitchen orany other room. Not Required 30

SOUN

DCO

NTRO

L

6

Adjacent studs to alignwith opposite sides

Lining fixed toevery second stud

6(b) - Staggered stud walls

Resilient channels ormounts when requiredfor sound insulation

6(c) - Single stud walls

FIGURE 6 - WALL FRAMING OPTIONS


Studs are not requiredto be in line

6(a) - Double stud walls

Two walls separatedby cavity (minimum20 mm recommended)

6.2 Wall FramingOptions

For separatingwalls betweendwellingsit isrecommendedthatdoublestudor staggeredstudsystemsbe used(referFigure6).Theseare the onlysystemswhichprovideadequateresistanceto impactsoundas wellas airbornesound.

Singlestudwalls shouldonlybe usedin situationswheresoundcontrolis not critical,suchas in spaces,below sub-floorsor betweengarages.

Wheresuspendedfloorsin adjoiningunitsare atdifferent levels, it is recommendedthatonlydoublestudwall systemsbe used(referFigure13).Satisfactoryimpactsoundresistancecannotbeachieved withstaggeredstudwalls or singlestudwalls(even withresilientchannels)wherefloorsare non-aligned.

Note: The variouswall systemsand fire grade liningoptionsare summarisedin tablesC,D and E. Liningsto be fixed in accordance with manufacturersrecommendationsandasoutlinedinSection8.

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Nogging NoggingJoists, trimmer ledger45 mm minimum thick

45 mm thick blockingor fire grade liningbetween bearers

Note:All details suitable for double stud orstaggered stud separating walls

Additional joists 45 mmminimum thick

Minimum45 mm thickblocking

Bearer

Joist

Bearer may be either sheeted with2 x 13 mm fire grade plasterboard

or additional 45 mm thicktimber blocking

Joists and bearers totransfer loads from

separating wall to masonry

7(a) - Masonry wall taken up to joists

7(b) - Masonry wall taken up to bearers

7(c) - Separating wall supported off masonry wall

7 CONSTRUCTION DETAILSAND BUILDING PRACTICE

Masonry wall minimum 90 mm widewith attached piers

Additional joists 45 mmminimum thick to maintainfire resistence

Joists as required to transfer loadsfrom separating wall to masonry

Termite barriers(through or overmasonry wall)

Additional 45 mm thick trimmer or blockingto maintain fire resistence

JoistSolid timber as requiredto transfer loads fromseparating wall tomasonry

FIGURE 7 - MASONRY SUB-FLOOR SEPARATING WALLS

To satisfy the BCA requirements and meet consumerexpectations the following details and practicesshould be adopted.


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Bearer Bearer

Bearer

Caulking Caulking

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Sawcut

Caulking

Sawcut

Caulking

Sawcut

Caulking

Sawcut

Caulking

Sawcut

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45 mm thick blocking

Bearer

Joist

Single stud wall between posts(termite resistant framing

below termite barrier)

75 mm

Timber sole plate

DPC

45 mmminimumthick joistsor ledger

Minimum 45 mm thickblocking, ledgeror trimmer

Joist

Joist supportedoff hangers or ledgers

Solid timber or framing to transfer wall loads to sub-floor wall

Structural post orpier (timber, brick or masonry)

Additionalblocking(minimum45 mm thick)

Solid timber totransfer wall loadsto sub-floor wall

Additional45 mm thick joist

Note:This detail only to be usedwhere no termite hazard exists

8(b) - Separating wall (double or staggered studs) supported off footing

8(a) - Single stud wall between concrete or masonry piers

FIGURE 8 - TIMBER FRAMED SUB-FLOOR SEPARATING WALLS

7.1 Sub-FloorSeparatingWalls

Separatingwalls mustbe continuousfromthe groundto the undersideof a non-combustibleroofor 450mmabove a combustibleroof. Walls below suspendedgroundfloorsmaybe masonry(referFigure7) ortimberframedwithfire gradelining(referFigure8).

Timberframedsub-floorseparatingwalls maybe eitherloadbearingextensionsof the separatingwall above, oralternatively non-loadbearinginfill walls betweenstructuralpiers.


Either 2 x 13 mm thick fire gradeplasterboard or additional 45 mm

thick timber to protect bearer

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Sawcut

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Sawcut

Caulking

Sawcut

Caulking

1 x 16 mm fire grade plasterboard or1 x 13 mm fire grade plasterboard plus

6 mm fibre cement to both sides

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Note:Refer figure 11-13 for floorintersections and figure 14for roof/ceiling intersections

Fire grade linings

Nogging may be staggered for2 layer linings or where singlelayer linings are fixed vertically

Acoustic insulation may beprovided (either betweenstuds in one leaf or in wallcavity)

5 - 10 mm gap below lining(refer manufacturer’srecommendation) gaps tobe caulked

20 mm minimum cavity toachieve Rw listed in table C

Overall width refer table C

Lining optionsa. 6 mm fibre cement plus 13 mm fire grade plasterboard

both sides (fibre cement may be inner or outer layer)

b.16 mm fire grade plasterboard to both sides(13 mm in non-load bearing walls)

Studs

600 mm max c/s

Opposing studs in thetwo leaves may bein-line or offset

FIGURE 9 - DOUBLE STUD WALLS (FRL 60/60/60)

7.2 DoubleStudSeparatingWalls

Separatingwalls maybe constructedwith twoindividualstudframedwalls (referFigure9 andTableC).

Intersectionsmustbe constructedto maintainthe fireresistancelevel andsoundperformance. Thefollowingtypicaldetailsshow recommendedbuildingpracticefor doublestudseparatingwalls:-

Figure10 - Two storey doublestudwalls

Figure12 - Bearerssupportedin separatingwall

Figure13 - Non-alignedfloors

Figure14 - Separatingwalls above ceilings

Figure15 - Intersectionswith internalwalls

Figure16 - Intersectionwithbrickveneerexternalwall

Figure17 - Non-alignedexternalwalls

Figure18 - Intersectionwith lightweightcladexternalwall.

NOTE: Complete isolation of the two structuralframes in double stud walls provides the bestairborneandimpactsoundresistance.

Figure9 - Doublestudwalls (typical)

Figure11 - Intersectionsbetweensuspendedfloorsandseparatingwall


Note:Refer figure 15-18or wall intersections

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TABLE C DOUBLE STUD WALLS FRL 60/60/60

Fire Grade Linings Studs Nominal Rw Overall Width(minimum size) Insulation (refer notes) (20 mm cavity)

One layer 16 mm fire grade 90 x 35 mm @ 50 mm 53 - 55to plasterboard both sides. 600 mm max. centres. 232 mm

Nil 47

(loadbearing or non-loadbearing walls) 70 x 45 mm of 50 mm 50 - 52600 mm max. centres 192 mm

(See Note 3)Nil 46

One layer 13 mm fire grade plasterboard 90 x 35 mm a 50 mm 53 - 55to both sides. 600 mm max.centres 226 mm

Nil 45

(non-loadbearing walls only) 70 x 35 mm at 50 mm 50 -52600 mm max. centres 186 mm

Nil 45

6 mm fibre cement plus 13 mm fire grade 90 x 35 mm @ 50 mm 58 -61plasterboard to both sides. 600 mm max. centres 238 mm

Nil 53 - 54

(See Note 4) 70 x 45 mm @ 50 mm 57 - 59600 mm max. centres. 198 mm

(70 x 35 mm innon-loadbearing walls) Nil 51 - 52

NOTES: 1. All of the above have “satisfactory resistance to impact sound”.2. The nominal Rw ratings listed are based upon a 20 mm cavity between walls with acoustic insulation (where listed)

50 mm thick polyester 350 kg/m . Different thicknesses and types of insulation will alter Rw values.(Refer lining manufacturer for actual tested Rw values).

3. 70 x 35 mm studs are not allowed in loadbearing fire rated walls.4. The fibre cement can be either the first layer (against the studs) or the second layer.

3


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Nogging behind edgeof lining

Studs continuous forfull 2 storey height

Resilient structuralconnections atmid floor level

Note:Isolating stairs fromwall provides superiorsound performance

10(a) - Studs continuous for two storeys

FIGURE 10 - TWO STOREY DOUBLE STUD WALLS

Caulking

Blocking or framing to transferupper wall loads to lower wall

Note:For load-bearing walls orwhere length of 2 storeywall exceeds 3.5 metresadditional lateral restraintmay be required

10(b) - Upper wall supported off lower wall

Caulking


Resilient structuralconnections atmid floor level

45 mm thick ledger

Note:For load-bearing walls orwhere length of 2 storeywall exceeds 3.5 metresadditional lateral restraintmay be required

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45 mm thicksolid timber

45 mm thickledger

Floor trussI beam etc.

Additional 45 mm thickjoists or ledgers to

maintain fire resistence

45 mm thick or 35 mm iffibre cement continued

through intersection

Fibre cementmay continuethrough

Note:In all cases, floors must be able to collapse in theevent of fire and leave the separating wall intact.

Joist

Joist

Joist hangeror angle

Joist hangeror angle

Top chord msupported off ledger

ay be

Joists to transfer loadfrom upper wall to

lower wall

Upper wall supported directlyoff lower walls

Fire grade linings(all layers) mustcontinue throughintersection or 45 mmthick solid timber providedto maintain fire resistence

FIGURE 11- INTERSECTIONS BETWEEN SUSPENDED FLOOR AND SEPARATING WALLS

11(b) - Joists perpendicular to separating walls11(a) - Joists paralled to separating walls

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CaulkingCaulking

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Bottom plate

Bottom plateupper wall

Top platelower wall

Nogging(45 mm thick)

45 mm thickjoists

Bearer

Slope top of bearerto allow rotation in theevent of collapse

Compressedmineral wool

Top platelower wall


Studs each side ofbearer to supportwall plates(45 mm thick)

Bearer

Fire grade liningsealed against bearer

Posts/joists directlybelow to supportbearer

Note:Upper wall must notbe supported off bearers

Note:Any of the floor intersection detailsfor double stud walls are suitablefor non aligned floors (refer figure 11).

Note:Staggered stud and single studwalls do not provide satisfactorilysound performance where floorsare non-aligned.

Additional 45 mm thick timberto maintain fire resistence

FIGURE 12 - BEARERS SUPPORTED OFF SEPARATING WALL

FIGURE 13 - NON-ALIGNED FLOORS

12(a) - Section / Elevation 12(b) - Plan view

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Notes:1. Additional ledgers/battens may be required to

support ceilings.

2. Top of wall cavity may need to be sealed to preventmoisture from entering cavity during construction.

3. These details are also suitable above staggeredstud walls.

Compressed fire resistantmineral woolbetween battens

Cavity between top ofwall and underside ofroof to be filled withcompressed fireresistant mineral wool

Ceiling

Double stud orstaggered studwalls

Fire grade liningmay continuethrough

45 mm thickledger

Single studwall

Truss

Two nailed gable trusses.Vertical truss members atmaximum 600 mm centres

Fire grade liningsas for separatingwall

Nogging tosupportedge oflining

Compressed fire resistant mineral woolbetween roof battens

70 mm minimumwidth betweenlinings

Compressed mineralwool to fill irregularitiesbetween truss and wall

14(b) - Separating wall continued up to roof

Figure 14(a) - Single stud wall

14(c) - Sheeted trusses

FIGURE 14 - SEPARATING WALLS ABOVE CEILINGS

Note:Refer to trussmanufacturers forminimum bearingrequirements

Batten(where required)to support ceiling


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Fibre cement first layercontinuous through joint

Minimum 35 mm thick studNogging at 600 mmspacing where no studsat intersecting wall

Fire grade lining continuousthrough joint

Nogging at 600 mmspacing where no studsat intersecting wall

15(a) - Fire grade linings continuous

Additional studsto fix linings

Additional stud

2 x 35 mm or 1 x 45 mm studs tomaintain fire resistence.

1 x 35 mm or 1 x 45 mm if jointreinforced with plasterers angle orintumescent sealant (refer figure 5)

15(b) - First layer (fibre cement) continuous

15(c) - Studs in intersecting wall used to maintain fire resistance

FIGURE 15 - INTERSECTIONS WITH INTERNAL WALLS

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Additional studs tosupport wall linings

Fire grade lining

Compressed mineralwool to fill cavity

Vertical DPC

DPC andfire-stoppingif required

Fire grade linings continuedthrough to brickwork


Fire grade lining

45 mm thick solid timber blocking

Vertical DPC

16(a) - Cavity blocked with timber 16(b) - Cavity filled with mineral wool

16(c) - Fire grade linings continued across cavity

FIGURE 16 - INTERSECTION WITH BRICK VENEER EXTERNAL WALL

dpc

Cavities blocked withmineral wool or solidtimber 45 mm thick)

Fire grade lining

Minimum45 mm thick

See note

Note:Although fire grade linings are not requiredin external walls, the linings would normallybe extended to the next intersection orconstruction joint

FIGURE 17 - INTERSECTION WITH NON-ALIGNED EXTERNAL WALL

Wall plate not to be continuousacross separating wall




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Fire gradelining

Compressed fire resistant mineral woolto fill any voids in external cladding(e.g. lapped weatherboards)

Minimum45 mm

thickstuds

Cladding

Breathertype

sarking

Note:Top and bottom plate to externalwall not to continue acrossseparating wall

Cladding

Mineralwool

Breathertype

sarking

18(a) - Non rated external wall

FIGURE 18 - INTERSECTION WITH LIGHTWEIGHT CLAD EXTERNAL WALL

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Fire grade lining

Fire grade lining

45 mmthick studs

Cladding

Breathertype

sarking

Cladding

Breathertype

sarking

Note:Top and bottom plate to external wallnot to continue across separating wall

Fire grade lining

Note:Any external cladding materials(e.g. Timber weatherboards)may be used over the top offire grade linings in fire ratedexternal walls

Figure 18(b) - External wall FRL 60/60/60(measured from outside only)

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Full width top plate (refer table D)

Full width bottom plate

Noggings kept clear of studswhich support lining toadjoining dwelling

Fire grade linings

35 mm thick noggings onedge between alternate studs

5 - 10 mm gap below lining(refer manufacturer’srecommendation) gap to becaulked

Overall width (refer table D)

Note:Figures 23, 25, 26 & 27for wall intersections

Note:Refer figures 20,21,22 & 24 forfloor and ceiling intersections

600 mm

300 mm 300 mm

Lining optionsa. 6mm fibre cement plus 13 mm fire grade plasterboard

both sides (fibre cement may be inner or outer layer)

b. Single layer fire grade plasterboard both sides (16 mmfor loadbearing walls, 13 mm for non-loadbearing walls)

Nogging betweenalternate studs

FIGURE 19 - STAGGERED STUD WALLS (FRL 60/60/60)

7.3 Staggered StudSeparatingWalls

Separatingwalls maybe constructedusinga singletopandbottomplate(120mmor 140mmwide)withalternatestudsstaggeredto alignwithoppositeedges.Firegradeliningsare fixed to alternatestuds. (referFigure19 andTableD).

Isolationof the structuralframe(exceptfor plates)providessatisfactoryresistanceto impactsoundaswellas airbornesound.

The followingtypicaldetailsshow recommendedbuildingpracticefor staggeredstudseparatingwalls tomaintainfire resistanceandsoundperformance:-

Figure21 - Intersectionsbetweensuspendedfloorsandseparatingwalls.

Figure22 - Bearerssupportedoff separatingwall.

Figure23 - Separatingwalls above ceilings.

Figure24 - Intersectionswith internalwalls

Figure25 - Intersectionwithbrickveneerexternalwall.

Figure26 - Non-alignedexternalwall.

Figure27 - Intersectionwith lightweightcladexternalwall.

NOTE: Staggered stud walls are not recommendedfor separating walls between units where floors arenotaligned. Satisfactorysoundperformancecannotbeachievedat floorintersections. Doublestudwallsare recommendedfornon-alignedfloors.

Figure19 - Staggeredstudwalls (typical)

Figure20 - Two storey staggeredstudwalls


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Nogging behind edgeof lining

Studs continuous for2 storeys

Resilient structural connectionsat mid floor level

Note:For loadbearing walls or wherelength of two storey wall exceeds3.5 metres additional lateralrestraint may be required


Refer figure 21 & 22 forintersection details

Full width top andbottom plates providelateral restraints

TABLE D STAGGERED STUD WALLS FRL 60/60/60

Fire Grade Linings Nominal Rw Studs Top and OverallInsulation (refer notes) (minimum size) bottom plates Width

One layer 16 mm fire grade 50 mm 49 - 51 90 x 35 140 x 35 172 mmto plasterboard both sides.

(loadbearing or non-loadbearing walls) Nil less than 45 90 x 35 120 x 35 152 mm(see Note 2)

less than 45 70 x 45 120 x 35 152 mm

One layer 13 mm fire grade plasterboard 50 mm 45 - 47 90 x 35 or 120 x 35 146mmto both sides. 70 x 35

(non-loadbearing walls only) Nil less than 45 (see Note 4)

6 mm fibre cement plus 13 mm fire grade 50 mm 56 - 57 90 x 25 140 x 35 178 mmplasterboard to both sides.

(See Note 5) Nil 50 120 x 35 158 mm(see Note 2)

50 mm 55 - 56 70 x 45 120 x 35 158 mm

Nil 49

NOTES: 1. All the above have “satisfactory resistance to impact sound”.. 2. 120 mm wide top and bottom plates with 90 mm wide studs do not allow

clearance for timber noggings. Studs in structural walls, designed in accordance with AS 1684, require solid nogging at 1350 mmmax. spacing. Studs in structural walls with no nogging or metal strapping require alternative design and certification.

3. The Rw values listed are based upon 50 mm thick polyester acoustic insulation 350 kg/m . Different types of insulation will givedifferent values. Refer lining manufacturers for actual tested Rw ratings.

4. 70 x 35 mm studs are not allowed in loadbearing fire rated walls.5. Fibre cement may be either first or second layer.

3

20(a) -Studs continuousfor 2 storeys

20(b) -Upper wall supportedby lower wall

FIGURE 20 - TWO STOREY STAGGERED STUD WALLS


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45 mm thick solid timber(35 mm if reinforced orfibre cement continuous)

45 mm thickor 35 mm thickif joint reinforcedor fibre cement sheetcontinued through(refer figure 5)

Additional 45 mm thick joist orledger (35 mm if reinforced) tomaintain fire resistance

Joists/blockingas necessary tosupport wall above

Joists/blockingas necessary to

support wall above

45 mm thick joists(35 mm if reinforced)to maintain fireresistance

Fibre cement firstlayer may continuethrough joint

Fibre cement firstlayer may continuethrough joint

Floor trussesmay be supportedby top chordoff ledger

Hanger orangle

Upper wall supported directly off lower wall

Note:Where ‘I’ beams or floor trusses are used, either fire gradelinings (all layers) must continue through intersection orsubstituted with solid timber to maintain fire resistance.

21(a) - Joists paralled to separating wall 21(b) - Joists perpendicular to separating wall


FIGURE 21 - INTERSECTIONS BETWEEN SUSPENDED FLOORS ON SEPARATING WALL

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Notes:1. Bearers must be

continuous through wall

2. Upper wall must besupported off bearers

NOT

NOT

Sawcut

Bottom plate

Top plate

Slope tops of bearersto allow bearers torotate in the event ofcollapse

Fire gradelinings Fire grade

linings

Bearers supported offadditional studs (posts)

Bearerssupportedoff additionalstuds (posts)

Seal aroundbearer

Studs to supporttop plate andwall above

Studs to supporttop plate andwall above

Upper wall supporteddirectly off lower wall

45 mm thick joists


Blocking (additional joists) to transfer upperwall loads to lower wall (not supported off bearer)

Seal around bearer

Additional joist45 mm thick

FIGURE 22 - BEARER SUPPORTED OFF STAGGERED STUD WALL

22(b) - Timber blocking to transfer wall loads

22(c) - Plan views


22(a) - Upper wall supported off lower wall

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Additional studs tosupport linings

45 mm minimumthickness (35 mm ifjoint reinforced)

Gap

Additional studs tosupport linings

45 mm thickness(35 mm if reinforced)

Gap

Gap

1 x 45 mm or2 x 35 mm joists

Gap

FIGURE 23 - INTERSECTION WITH INTERNAL WALLS


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Cavity to be blocked with eitherfire resistant mineral wool,solid timber or fire grade liningscontinued to masonry(as for double stud walls - figure 16)

Top plate and bottom platemust not be continued overseparating wall

FIGURE 25 - INTERSECTION WITH EXTERNAL BRICK VENEER WALL

Note:Single stud walls or sheeted trusses may be usedin ceiling spaces above staggered stud separatingwalls. Refer figure 14 for typical details.

Cavity between top of walland underside of roofto be filled with compressedfire resistant mineral wool

Fire-rated wall

Truss

45 mm thick ledgerto support ceilingand trusses.

Use truss boots asrequired to supporttrusses on ledger

Nogging behindedge of linings

FIGURE 24 - SEPARATING WALLS ABOVE CEILINGS


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Compressedfire resistantmineral wooland d.p.c.

See note

Additional stud tosupport lining

Note:Although fire grade liningis not required in external walls,the linings would normally beextended to the next intersection

FIGURE 26 - INTERSECTION WITH NON-ALIGNED EXTERNAL WALLS

Cladding

fire resistantmineral woolto fill voids inexternalcladding

Breather typesarking


Top and bottom plate toexternal wall must notcontinue acrossseparating wall

Cladding

Mineralwool

Breathertypesarking

Note:External wall may be fire rated (from the outside) withcontinuous fire grade lining inside cladding and sarking

FIGURE 27 - INTERSECTION WITH LIGHTWEIGHT CLAD EXTERNAL WALLS

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TABLE E SINGLE STUD WALLS FRL 60/60/60

Fire Grade Linings Nominal Rw Studs OverallFixing Insulation (refer notes) (minimum size) Width

One layer 16 mm fire grade Resilient channels 50 49 90 x 35 135 mmto plasterboard both sides. or mount to

one side (129 mmfor 13 mm

Nil less than 45 lining)

(13 mm in non-loadbearing walls) Furring channels 50 50 90 x 35 157 mmwith resilient

mounted clips (151 mmto one side Nil less than 45 for 13 mm

lining)

Direct to Nil to less than 45 90 x 35 122 mmstuds filled cavity (116 mm

for 13 mmlining)

6 mm fibre cement plus 13 mm Direct to Nil 47 - 49 90 x 35 128 mmfire grade plasterboard to both sides. studs

Nil less than 45 70 x 45 108 mm

NOTE: 1. Lining fixed with resilient channels or mounts should face likely noise source (eg. wet areas) to provide impact sound resistance.Single stud walls with linings fixed to studs should only be used in locations where sound insulation is not critical (eg.between garages or in sub-floor or roof spaces above ceilings).

2. The nominal Rw ratings listed are based upon a 20 mm cavity between walls with acoustic insulation (where listed)50 mm thick polyester 350 kg/m . Different thicknesses and types of insulation will alter Rw values.(Refer lining manufacturer for actual tested Rw values).

3. 70 x 35 mm studs are not allowed in loadbearing fire rated walls.4. The fibre cement can be either the first layer (against the studs) or the second layer.

3

7.4 SingleStudSeparatingWalls

Wherenoisereductionis not requiredby the BCA(eg.BetweenClass10 a garagesor carports)or in situationswheresoundtransmissionis lesscritical(eg. In sub-floorandceilingspaces),singlestudframedseparatingwalls maybe used. (referTableE).

Note:An acceptablelevel of sound transmissionlosscan only be achieved in singlestud wallswith the useof resilient channels or resiliently mounted furringchannels. These systems however are onlyrecommended for single storey, single roomapplications (e.g. wet areas) because soundperformancecannotbemaintainedat intersections.


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Compressed mineral wool

Compressed fire resistant mineral wool

45 mm thick blocking orfire grade lining takenup to roofing (where noeaves lining provided)

45 mm thick blocking wherefire grade lining not takenup to roofing

Cladding

Breather typesarking

Fire grade lining

Non ratedinternal linings

Non ratedinternal linings

Note:Fire rating needsonly to be fromthe outside

Non combustibleeaves lining(e.g. Fibre cement)

Masonry90 mmminimumthicknessprovidesFRL 60/60/60

Note:Floor may be supported withinfire rated external wall

FIGURE 28 - FIRE GRADE LINING ORBLOCKING CONTINUED UP TO ROOF

FIGURE 29 - FIRE RATED WALL(MASONRY OR FIRE GRADE LINING)

TO NON-COMBUSTIBLE EAVES LINING

7.5 ExternalWalls

Externalwalls within900mmof a sideor nearboundaryor closerthan1800mmto anotherbuildingare requiredto be FRL60/60/60( -/60/60if non-loadbearing). This fire resistancelevel needsonly to be attainedfromthe outside.

FRL60/60/60externalwalls can be either:-

• Brickveneer(minimum90 mmthick)brickswithany ratedor non-ratedinternallinings.

• 2 x 13 mmfire gradeplasterboardto externalfacecoveredby waterproofcladding(maybecombustiblematerial).Any ratedor non-ratedinternallining

• Any FRL60/60/60wall systems(referTablesC, DandE) withfire gradeliningto bothsides,withexternalface coveredby waterproofcladding(maybe combustiblematerial).

Fire ratedwall to extendup to non-combustibleroofingor non-combustibleeaves lining(referFigure28 &29).

Detailingof intersectionsbetweenfire ratedexternalwalls andseparatingwalls is exactlythe sameas fornon-ratedexternalwalls. (Fire resistanceof separatingwall to be effectively continuedthroughexternalwallandany associatedcavity) (referFigures17,18,25and27).

Separatingwalls musteffectively extendthroughanyvoid in ceilingsandeaves (referFigure30).

Wherefloorsare non-alignedor wherea singlestoreydwellingadjoinsa two storey dwelling,the separatingwall andexternalwall above the lower roofshallbe asshown on Figure31. Theseparatingwall betweendwellingsor betweendwellingandceilingspaceshallbe FRL60/60/60frombothsides. Theexternalwallabove the lower roof requiresFRL60/60/60measuredfromthe outsideonly. ( - /60/60for non-loadbearingwalls).

(ReferFigure2)

• 1 x 16 mmwetarea fire gradeplasterboardtoexternalface coveredby waterproofcladdingfixedto verticalor horizontalbattensat 600mmcentres.10 mmstandardplasterboardinternallining.

NOTE: Eaves linings are required to be non-combustiblebut not fire rated.Fibre cementproductssatisfythisrequirement.

NOTE: Suspendedfloors may be supporteddirectlyoff rated or non-rated external walls. There is norequirement for floors to collapse away fromexternalwallsin theeventof fire.

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Fire grade lining, and framingto extend through eaves

Cavity between top of wall and underside of roofing to befilled with compressed fire resistant mineral wool

Non-combustible eaves lining

Fire rated separating wallto be continued throughtimber wall and cavity(refer figure 16, 17, 18, 25 & 27)

Fire rated separating wallextended to underside ofroofing

Non fire-rated ceiling

Fire-rated separating wall

Note:Internal firegrade linings maynot be necessaryabove roof butare generallycontinued up toceiling

Fire grade linings toseparate unit fromceiling space

Mineral wool betweenbattens

Ledger to support ceiling

45 mm thick blocking or ledger

Note:The external wall above a lowerroof to have FRL 60/60/60measured from the outside

Flashing

Fire grade lining

Breather type sarking

External cladding

FIGURE 30 -EXTENDING SEPARATING WALLTHROUGH EAVES

FIGURE 31 -EXTERNAL WALL ABOVE LOWER ROOF

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300 mmmin.

300 mmmin.

Not more than one electrical recess ineach wall face between any two studs

16 mm fire gradeplasterboard baffle

Gap between baffle and oppositestuds in staggered stud walls

16 mm fire gradeplasterboard baffle Wet area sealant

Acousticinsulation

Timber supportbattens

50 mmminimum

300 mm

16 mm fire grade plasterboard baffle

Wet area sealant

Acoustic insulationbetween plumbingfixtures and fittings

Fire grade linings

Resilient mounts

Timber battens

300 mm

FIGURE 32 -BAFFLE BETWEEN ELECTRICAL OUTLETS

OR SWITCHES

FIGURE 33 - BAFFLE AND INSULATION BETWEEN PLUMBING OUTLETS

7.6 PlumbingandElectricalServices

The installationof plumbingor electricalservicesinseparatingwalls have the potentialto reducethe fireresistanceandsoundperformance. Wherepossibletheseservicesshouldnot be locatedwithinfireresistantwalls (ie. placedin adjoiningpartitions,ducts,or over the face of fire gradelinings(behindbattenedout falsewall).

Whereserviceswithinseparatingwalls cannotbeavoided,the integrityof the wall mustbe maintainedfor bothfire resistanceandsoundinsulation. Thefollowingpracticesshouldbe adopted:-

(a) All holes,gaps or other irregularitiesassociatedwithpenetrationsthroughfire-ratedelementsmustbe sealedor mustsealduringa fire.

(b) Plumbingfittingsand/orelectricaloutletsshouldpreferablynot be backto back(ie. penetrateonlyone face betweentwo studs).

(c) Electricaloutletswhichare backto back,shouldhave eitherfire ratedboxes (withintumescentbacking)or be installedwith16 mmthickfiregradeplasterboardbaffle extending300mmaboveandbelow fittings(referFigure32).

(d) Backto back plumbingpenetrationsshouldbeseparatedby a 16 mmfire gradeplasterboardbaffle extending300mmabove and300mmbelow penetration. 50 mmthickacousticinsulationshouldalsobe installed(referFigure33).

(e) Penetrationsfor servicesshouldbe kept aminimumof 50 mmfromstuds.

(f) Pipesmustnot be fixed to linings.

(g) Pipesshouldbe supportedoff battensbetweenstudsor kept clearof studswithresilientmounts).

(h) Baths,showerbases,sinks,basinsmustnot berecessedinto fire ratedwalls. Firegradeliningsmustbe continuousbehindfixtures(referFigure34).

NOTE: Where plumbing services are required onnoise sensitivewalls, it is recommendedthat a falsewall be built in front of the fire and sound-rated wallandtheplumbingbeplacedintothis falsewall.

NOTE: Plastic pipes and fittings generally havebettersoundperformancethanmetal.

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Void created bybattens can beused for services

Lining boardsuitablefor wet areas

Timber batten

Timber supportbatten fixed tostuds

Fire grade lining(e.g. 16 mm firegrade plasterboard)

Edge of bath/shower not tobe recessedinto fire-rated wall

Timber supportbatten fixed tostuds

Lining board suitablefor wet areas

Vanity or kitchen unitnot to be recessedinto fire-rated wall

Fire grade linings(e.g. 6 mm fibre cement plus13 mm fire grade plasterboard)

Lining board suitablefor wet areas

Fire grade linings

Caulking to 5-10 mm gapFlashing fixed toface of rated wall

34(a) - Edge of bath

34(b) - Vanity or kitchen bench

34(c) - Wet area floors

FIGURE 34 - WET AREA INSTALLATION


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FIGURE 35 - BOX GUTTERS

45 mm thick ledger Hanger (truss boot)

35(b) - Roof framing supported offhangers and ledgers

45 mm thick blockingbetween trusses

Bottom chords extended(refer truss manufacturer)

35(a) - Roof framing on top ofseparating wall (not to be continuous)

Breather type sarking

Firegradelinings

Hanger (truss boot)

45 mm thick ledger

Cladding

Flashing

Note:Bottom chord extended to boxgutter width (refer truss manufacturer)

35(c) - Box gutter at parapet or for lower roof

7.7 BoxedGutters

Figure35 shows typicaldetailsfor boxed guttersatseparatingwalls.


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8 FIXINGS OF LININGS

To achieve FRL60/60/60in separatingwalls thefollowingfire gradeliningsand required:-

(a)- 1 x 16 mmfire gradeplasterboardto bothfaces

or

- 1 x 13 mmfire gradeplasterboardplus1 x 6 mmfibrecementto bothfaces (eithersheet fixedfirst)

(b)- 1 x 13 mmfire gradeplasterboardto bothfaces

(or eitherof the loadbearingoptions).

Different liningmanufacturershave differentrequirementsfor nail sizesandspacings. Liningsmustbe installedstrictlyin accordancewithmanufacturer’sinstructions.

Internalandexternalcornerjunctionsmustbe arrangedto providesupportto both liningboards.Additionalstudsor noggingsmaybe required.

All verticalbutt jointsshallbe on studswith jointsstaggered. (ie. sheetson sameface as wellas sheetsonthe oppositeface mustnot have verticaljointson thesamestud).

Wheremultiplelayer liningsare used,horizontalandverticaljointsshallbe staggered. Sheetscan be fixedhorizontally, verticallyor a mixtureof both. The fibrecementsheetsmaybe eitherthe first or secondlayer.

At internalwall junctionsandat intersectionsbetweenseparatingwalls andceilings,any gaps betweenliningsshallbe sealedwithflexiblefire resistantsealer.

LoadbearingWalls

Non-LoadbearingWalls

NOTE: Staggered nogging may be used for duallayer systems, or where single layers are fixedverticallywithnohorizontaljoints.

NOTE: In FRL 60/60/60systemsfibre cementsheetsmaybeeitherfirst orsecondlayer.

NOTE: (ReferFigure 4 for the use of timberblockingand Figure 5 for strengthening of joints with eitherintumescent putty, plasterer’s angle or continuouslinings.

A gap of between5 and10 mmshallbe kept at thebottomof fire gradeliningsat floor level. Gap to becaulked witha fire resistantsealer.

NOTE: Caulking should generally be flexible toallow for timber movement. Non-flexible caulking(eg. Vermiculite plaster) may be used to seal gapsbetween lining and concrete floors where seasonedframingisused.


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Studs at 600 mmcentres

Studs at 600 mmcentres

Joints centred onstud

Nail spacings to manufacturers’requirements


Note:Vertical joints on oppositefaces to be staggered(i.e. Not on the same stud)



Vertical jointsstaggered

Vertical jointsstaggered

36(a) - Single layer fire grade plasterboard fixed horizontally

36(b) - Single layer fire grade plasterboard fixed vertically

36(c) - Fibre cement in conjunction with fire grade plasterboard

FIGURE 36 - FIXING OF LININGS

For informationregardingMRTFCpleasecontact:

New South Wales - TDA

Telephone (02) 9360 3088

Queensland - TRADAC

Telephone (07) 3358 1400

South Australia - TDA

Telephone (08) 8297 0044

Victoria - TAC

Telephone (03) 9877 2011

Western Australia - TAC

Telephone (08) 9380 4411

Tasmania - TTPB

Phone (03) 6224 1033

Timber Development Association of NSW

13-29 Nichols Street, Surrey Hills

New South Wales 2010

Fax (02) 9360 3464

Timber Research And Development Advisory Council

500 Brunswick Street, Fortitude Valley

Queensland 4006

Fax (07) 3358 1411

Timber Development Association of South Australia

113 Anzac Highway, Ashford

South Australia 5035

Fax (08) 8297 2772

Timber Advisory Centre

180 Whitehorse Road, Blackburn

Victoria 3130

Fax (03) 9877 6663

Timber Advisory Centre of Western Australia

55 Salvado Road, Subiaco

Western Australia 6008

Fax (08) 9380 4477

Tasmanian Timber Promotion Board

Suite 22, 11 Morrison Street, Hobart,

Tasmania 7000

Fax (03) 6224 1030

Plywood Association of Australia

Phone (07) 3854 1228

Pine Australia

Phone (Free Call) 1800 007 463

3 Dunlop Street, Newstead

Queensland 4006

Fax (07) 3252 4769

830 High Street, Kew East

Victoria 3102

Fax (03) 9859 2466

w bee www.timber.org.au/mrtfc

This publication is a joint venture between the National Timber Development Counciland the Forest and Wood Products Research and Development Corporation.

The FWPRDC is jointly funded by the Commonwealth Government and theAustralian forest and wood products industry.

© FWPRDC 2000 ,Printed June 2000

Members of theNational Timber Development Council

ATIF - Australian Timber Importers Federation

FIAT - Forest Industries Association of Tasmania

FIFWA - Forest Industries Federation (Western Australia) Inc.

FPA - New South Wales Forest Products Association Ltd.

FWPRDC - Forest & Wood Products Reseach & Development Corporation

PA - Pine Australia Ltd.

PAA - Plywood Association of Australia Ltd.

QTB - Queensland Timber Board

TDA (NSW) - Timber Development Association (New South Wales) Ltd.

TDA (SA) -

NAFI - National Association of Forest Industries

Timber Development Association (South Australia) Inc.

TPC - Timber Promotion Council of Victoria

TRADAC - Timber Research and Development Advisory Council (Qld)

VAFI - Victorian Association of Forest Industries

MULTI-RESIDENTIALTIMBER FRAMED CONSTRUCTION

FOREST & WOOD PRODUCTSRESEARCH & DEVELOPMENT CORPORATION

class 1a buildings - bretts · perpendicular to the boundary) of a class 1a building within 600 mm...

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