MULTI-RESIDENTIAL TIMBER FRAMED CONSTRUCTION Class 1a Buildings DESIGN & CONSTRUCTION MANUAL National Timber Development Council PREFACE CONTENTS The deemedto satisfyprovisionsof the BuildingCode ofAustralia(BCA96) describethe requirementsand limitationsfor timberframedmulti-residential buildings. Theseprovisionsallow timberframingin:- Section 1 SCOPE 2 Section 2 ABBREVIATIONS, DEFINITIONS, TERMINOLOGY 2 Section 3 BCA REQUIREMENTS 3.1 Performance Provisions 3.2 Deemed to Satisfy Provisions 3.3 Separating Walls 3.4 External Walls 3.5 Roof Lights 3.6 SmokeAlarms 5 5 5 6 7 7 7 Section 4 STRUCTURAL REQUIREMENTS 4.1 Timber Member Design 4.2 Noggings 4.3 Notches, Cuts and Holes 8 8 8 8 " " " All Class 1 buildings Class 2 buildingsto 3 storeys (4 storeys wheregroundstorey is concrete/masonry carparking) Class 3 buildingsto 2 storeys. This manualoutlinesthe BCA requirementsfor Class 1a buildingsand associatedClass 10 buildingswith respectto fire separationand noise controland describesthe materials,detailsand construction practicesthat are recommendedto satisfythese requirements. The information provided will enable designers, local authorities, developers and builders to achieve practical and economical solutions for Multi-Residential Timber Framed Construction (MRTFC). A companion publication ”MRTFC Design & Construction Manual – Class 2 & 3 Buildings” describes the requirements for these building classifications. The information, opinions, advice and recommendations contained in this publication have been prepared with due care. They are offered only for the purpose of providing useful information to assist those interested in technical matters associated with the specification and use of timber and timber products. Whilst every effort has been made to ensure that this publication is in accordance with current technology, it is not intended as an exhaustive statement of all relevant data, and as successful design and construction depends upon numerous factors outside the scope of this publication, the authors and publishers accept no responsibility for errors in, or omissions from, this publication, nor for specifications or work done or omitted to be done in reliance on this publication. Section 5 FIRE SEPARATION 5.1 Fire Resistance Level (FRL) 5.2 Solid Timber at Intersections 5.3 Strengthened Joints 9 9 10 11 Section 6 SOUND CONTROL 6.1 Weighted Sound Reduction Index (Rw) 6.2 Wall Framing Options 12 12 13 Section 7 CONSTRUCTION PRACTICEAND DETAILS 14 7.1 Sub-floor Separating Walls 15 7.2 Double Stud Separating Walls 16 Intersections between suspended floors and 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. 7.3 Staggered Stud Separating Walls Intersections between suspended floors and separating walls Bearers supported off separating wall Intersection with internal walls Separating walls above ceilings Intersection with brick veneer external wall Non-aligned external wall © FWPRDC 2000 Intersection with lightweight clad external wall. First Edition - June 2000 7.4 7.5 7.6 7.7 Single Stud Separating Walls External Walls Plumbing and Electrical Services Boxed Gutters Section 8 FIXING OF LININGS MRTFC Class 1a - Design & Construction Manual 19 20 20 21 22 23 23 24 26 28 29 30 31 31 32 32 33 34 36 38 39 1 1 SCOPE 2 This manualcontainsthe timberindustry’s recommendationsfor the designand constructionof timberframedClass 1a attacheddwellings(duplexes, townhouses,villas etc) and associatedClass 10 buildings(carportsetc). It provides informationon materialsand systemsthat have been developed,as well as detailsand buildingpracticesthat are necessary to satisfythe fire resistance,and soundcontrol requirementscontainedin the “deemedto satisfy” provisionof the BuildingCode ofAustralia(BCA96). TERMINOLOGY SCOPE 1 NOTE: This manual describes the requirements for Class 1a attached dwellings and associated Class 10abuildings. NOTE: Buildingswhich containseparate residential units above or below one another, as well as side by side or which have common space above or below dwellings(ie. common ceiling spaces, common subfloor space, commercial car parking etc.) are classified as Class 2 or 3. These are described in supporting publication “MRTFC Design and ConstructionManual– Class2 and3 Buildings”. The constructiondetailsand practicesincluded,will generallycover the majorityof situations. They should,however be regardedas typical,with modificationspermitted,as long as the requiredfire and soundperformanceis maintained. NOTE: It is not intendedthat this manualprovide an exhaustive statement of all the methods or construction details appropriate for this form of construction. Although the majority of systems available at the time of publication have been included, manufacturers will continue to develop new and alternative systems, and practices will invariably evolve which meet either the deemed to satisfyor performancerequirementsof the BCA. CAULKING(FIREGRADESEALANT) Fire gradematerialused to fill gaps at jointsand intersectionsin fire gradeliningsto maintainthe fire resistancelevel (refer also “IntumescentSealant”). NOTE: Caulking material may also need to be flexible to allow for movement and/or waterproof for externalor wet area applications. CLASS1 One or more buildings,whichin associationconstitute– (a) Class1a – a singledwellingbeing– a detached house;or one or more attacheddwellings,each beinga building,separatedby a fire-resistingwall, includinga row house,terracehouse,town house or villa unit; or (b) Class1b – a boardinghouse,guest house,hostelor the like with a total floor area not exceeding300 m2 and in whichnot more than 12 personswould ordinarilybe resident; whichis not locatedabove or below anotherdwellingor anotherClass of buildingother than a private garage. NOTE: Class 1a detached houses and Class 1b buildings (small boarding houses) have no fire resistanceandsoundcontrol requirements. CLASS10 A non-habitablebuildingor structurebeing– (a) Class10a – a non-habitablebuildingbeinga private garage,carport,shed, or the like; or (b) Class10b – a structurebeinga fence,mast,antenna, retainingor free-standingwall, swimmingpool, or the like. DEEMEDTO SATISFYPROVISIONS Provisionscontainedin Section3 of the BCA whichare deemedto complywith the performancerequirements. DWELLING A Class 1a building 2 ABBREVIATIONS, DEFINITIONS, TERMINOLOGY FRL - FIRERESISTANCELEVEL The fire resistance,expressedas a time (in minutes)that a structuralmemberor part of a buildingmust achieve with respectto - The following abbreviationsand definitionsapplyin the use of this manual. (a) structuraladequacy - (ie. maintainstabilityand adequateloadbearingcapacity) BCA BuildingCode ofAustralia1996 - Volume2, Class 1 and Class 10 BuildingsHousingProvisions. (b) integrity -(ie. resist passageof flames,smoke and hot gases) BUILDINGSOLUTION A solutionwhicheither:(a) complieswith the deemedto satisfyprovisionsof the BCA or (b) is an alternative solutionwhichcomplieswith the performancerequirements. 2 (c) insulation- (ie. maintaina specified temperature on the surface not exposedto fire) and expressedin that order (e.g. FRL 60/60/60for separatingwalls). NOTE:A dash,for examplein 60/ - / - , meansthere is no integrity or insulation requirement for that memberor partof the building. MRTFC Class 1a - Design & Construction Manual FIRE-SOURCEFEATURE NON-COMBUSTIBLE (a) the far boundaryof a road adjoiningthe allotment;or (b) a side or rear boundaryof the allotment;or (a) appliedto a material- meansnot deemed combustible underAS 1530.1CombustibilityTests for Materials;and (c) an externalwall of anotherbuildingon the allotmentwhichis not of Class 10. FIREGRADELINING Fire gradeplasterboardor a combinationof fire grade plasterboardand fibre cementused to provide the requiredFRL in a separatingwall or externalwall. HABITABLEROOM A room used for normaldomesticactivities,and – (a) includesa bedroom,living room,loungeroom, musicroom,televisionroom,kitchen,diningroom, sewing room,study, playroom,familyroom and sunroom;but (b) excludesa bathroomlaundry, water closet,pantry, walk-inwardrobe,corridor, hallway, lobby, photographicdarkroom,clothes-dryingroom,and other spacesof a specialisednatureoccupied neitherfrequentlynor for extendedperiods. INTUMESCENTSEALANT(INTUMESCENT PUTTY) A fire resistantmaterialused in fire gradelinings(at joints,penetrationsetc) whichexpandswhen exposed to fire to fill and/orseal gaps and maintainsthe required fire resistancelevel. MINERALWOOL (FIRERESISTANT) Compressible,non-combustible,fire resistantmaterial used to fill cavities and maintainthe fire resistanceor restrictthe passageof smoke and gases. NOTE: The mineral wool to be used in all applications in this manual, must be fire resistant and therefore must have a fusion temperature in excess of 1160°C. ‘Rockwool’ type products generally meet these requirements, whilst ‘glasswool’productsdo not. To maintain FRL 60/60/60 the fire resistant mineral wool must be a minimum width of 120 mm and compressesto 85%of originalthickness. MRTFC Multi-ResidentialTimberFramedConstruction. MRTFC Class 1a - Design & Construction Manual 2 TERMINOLOGY FIRESTOP Fire gradematerialused to close a gap or imperfection of fit that occurswherea servicepassesthrougha firerated elementor system. (b) appliedto constructionor part of a buildingmeansconstructedwhollyof materialsthat are not deemed combustible. PERFORMANCEREQUIREMENTS Requirementsin the BCA whichstate the level of performancewhicha buildingsolutionmust meet. RESILIENTCHANNEL/MOUNT Proprietarysupportfor liningsdesignedto improve soundinsulationand reducesoundtransmission. Rw (refer “WeightedSoundReductionIndex”) SEPARATINGWALL (PARTYWALL) A wall that is commonto adjoiningClass 1a buildings (refer Figure1 and Section3.2). NOTE: Walls that are common to or between adjoining buildings other than Class 1(a), or walls between a Class 1(a) building and another classificationare referred to as commonwalls or fire walls (refer “MRTFC – Design & Construction Manual– Class2 & 3 Buildings”). STC (SOUNDTRANSMISSIONCLASS) The methodof ratingthe airbornesoundtransmission performanceof a wall or floor/ceilingelementprior to 1999. NOTE: The acoustic ratings required by the BCA (Amendment6 - 1999) are now called the “weighted sound reduction index” with the symbol Rw, consistentwithAS / NZS1276.11999. Test results for buildings and building elements with STC values in accordance with the 1979 version of AS 1276 remain valid (the STC value being the Rw value). SITE The part of the allotmentof land on whicha building standsor is to be erected. NOTE: Class1a buildingsmay be on their own separate allotmentwithina group title, communitytitle or Torrens title subdivision(ie. where the separating wall is on the site boundary).Alternativelyseveral Class1a buildingsmay be on a singleallotment,with each dwellingsold underBuildingUnit or Strata title. WEIGHTEDSOUNDREDUCTIONINDEX(Rw) The ratingof soundinsulationin a buildingor building elementas describedinAS/NZS1267.11999. 3 Parapets above combustible roof TERMINOLOGY 2 dwelling 3 dwelling 1 dwelling 4 dwelling 2 External walls to be fire-rated if within 900 mm of boundary or 1800 mm of another building Separating wall continued up to underside of non-combustible roof Fire rated external wall above lower roof dwelling 5 dwelling 8 dwelling 6 dwelling 9 dwelling 7 Suspended floor Separating wall continued down to ground Fire rated external wall continued up to underside of combustible roof or non combustible eaves lining dwelling 10 dwelling 11 dwelling 12 Private garages may be under or within class 1a dwelling dwelling 13 Attached carports or garages (class 10 a) FIGURE 1 - TYPICAL CLASS 1a BUILDINGS 4 MRTFC Class 1a - Design & Construction Manual 3 BCA REQUIREMENTS PerformanceProvisions The following summarisesthe BCA’s objectives and performancerequirementsfor Class 1 and 10 buildings with respectto: a) Structure - withstandthe combinationof loads and other actionsto whichthey may be reasonably subjected. b) DampandWeatherproofing – provide resistance to moisturefrom the outsideand moisturerising from the ground. c) Fire Safety – protectbuildingsfrom the spreadof fire and provide safeguardsso that occupantsmay safelyevacuate. d) HealthandAmenity i) WetAreasnot to createunhealthy or dangerous conditions 3.2 Deemedto SatisfyProvisions The BCA contains“deemedto satisfyprovisions”that are acceptableformsof constructionwhichcomply with the performancerequirements.The simplestway to obtainapproval or certificationfor a projectis to complywith the deemedto satisfyprovisions. For attachedClass 1a MRTFC projectsthe majorityof the deemedto satisfyrequirements(as well as the performanceprovisions)are the same as the requirementsfor detachedhouses. The requirements are the same for:- • dampand weatherproofing • kitchensand wet areas • room sizes and heights ii) Roomheightsto be suitablefor the intendeduse • light and ventilation iii)Provide facilitiesfor personalhygiene, laundering,food preparationand cooking • safe access. iv) Provide adequatenaturaland artificial light v) Provide adequateventilation vi) Prevent unduesoundtransmissionbetween dwellings. e) Safe MovementandAccess i) Provide safe accessto and withinthe building ii) Restrictaccess(youngchildren)to swimming pools. A buildingsolutionmust satisfyall of the performance provisionsof the BCA. The buildingmay eithersatisfy the “deemedto satisfy”provisionsof the BCA (and as describedin the manual)or be an “alternative solution” whichcan be shown to satisfythe performance provisions. 3 • structuraldesign(useAS 1684-1999‘Residential TimberFramedConstruction) BCA REQUIREMENTS 3.1 The BCA requirementsfor attacheddwellingswhich are in additionto or differentfrom those for detached dwellingsare:(a) fire separationbetweendwellings - separating walls must be of fire resistingconstruction. Externalwalls must also be fire resistingif close to a boundaryor anotherbuilding. (b) soundcontrol betweendwellings - separating walls must reducesoundtransmission(noise). NOTE: This manualcontainstimberframed systems, construction details and building practices which satisfy the “deemed to satisfy” fire separation and soundcontrol requirementsof the BCA. NOTE: For guidance on gaining approval for an alternative solution using the performance provisions of the BCA refer to MRTFC Information BulletinNo. 2. MRTFC Class 1a - Design & Construction Manual 5 3.3 SeparatingWalls NOTE: Cavities to be maximum 50 mm width. flashing, dpc etc to be provided to maintain weatherproofing where cavitiesare packed. To satisfythe BCA deemedto satisfyfire and sound requirements,separatingwalls betweenClass 1a dwellingsshall:(a) be continuousfrom footing(or concreteslab on ground)to undersideof non-combustibleroof covering or 450 mm above combustibleroof. (refer Figure1). (f) extendthroughto the outsideof and effectively separatevoids in boxed eaves etc (refer Figure30). (g) have a soundtransmissionclass of not less than:i) Rw 45 betweenhabitableroomsin adjoining dwellings. (b) have a fire resistancelevel not less than FRL 60/60/60(-/60/60if non-loadbearing) (refer Section5.1) (c) not be crossedby timbermembers(or other combustiblebuildingelements)other than roof battens(maximumsize 75 x 50 mm). BCA REQUIREMENTS 3 ii) Rw 45 betweenkitchensor wet areas in adjoiningdwellings. iii)Rw 50 (as well as resistanceto impactsound) betweena kitchen,bathroom,WC or laundryin one dwellingand a habitableroom in an adjoiningdwelling. NOTE: All intersections must be constructedso that in the event of fire, floors, ceilings, roof, internal walls etc (within the dwelling on fire) are able to collapsebut leavethe separatingwallintact. NOTE: The above BCA sound requirements should be regarded as minimum regulatory standards. Higher levels of sound resistance are recommended to satisfyconsumerexpectations. (d) have any void betweentop of wall and undersideof roofing (ie. betweenbattens)filled with solid timber, fire resistantmineralwool or other suitable fire resistingmaterial. (e) extendthroughto the outsideof externalwalls (ie. have cavities in brick veneer externalwalls packed with fire resistantmineralwool, solid timberblockingor other suitablefire resisting material- (refer Figure16). Note: These portions of wall not required to be fire rated because they are greater than 900 mm from boundary and greater than 1800 mm from other buildings measured at right angles Boundary Note: These walls not required to be fire rated because they are greater than 900 mm from boundary and greater than 1800 mm from other buildings measured at right angles 900 mm 1800 mm The portion of the wall within 900 mm of boundary FRL 60/60/60 dwelling 2 dwelling 3 dwelling 1 Wall within 900 mm of boundary measured at right angles to have FRL 60/60/60 dwelling 4 900 mm Walls within 1800 mm of another building to have FRL 60/60/60 FIGURE 2 - FIRE RESISTING EXTERNAL WALLS 6 MRTFC Class 1a - Design & Construction Manual ExternalWalls In all statesexcept SouthAustralia,externalwalls in Class 1a buildingsare requiredto be fire-resistingif less than 900 mm from rear or side boundariesor less than 1800 mm from anotherbuilding.The clearances are measuredat right angles(90°) to eitherthe boundaryor the externalwall of anotherbuilding(refer Figure2). NOTE: State and Local authorities throughout Australia may have planning regulations which containdifferent sitingrequirements. TheSouthAustralianHousingCoderequires: External walls (including those at an angle or perpendicular to the boundary) of a Class 1a building within 600 mm of the allotment boundary, or within 1200 mm of another building on the same allotment, shall be of fire-resisting construction to the underside of non-combustibleroof lining or noncombustible eaves lining to resist the spread of fire from the outside except where protected by a wall of fire-resistingconstruction(e.g. a ‘wingwall’). Fire resistingexternalwalls must have a fire resistance level not less than FRL 60/60/60when measuredfrom the outside.( - /60/60if non-loadbearing). NOTE: Fire rated external walls in Class 1a buildings do not require fire resistance from the inside. Fire resistingexternalwalls must extendto the undersideof a non-combustibleroof covering or to a non-combustibleeaves lining(refer Figure27). 3.5 Roof Lights Roof lights,(skylightsetc) whichcontaincombustible material,may be installedin a roof whichis requiredto have a non-combustiblecovering provided:(a) the area of the roof light is not more than 20% of the roof area (b)the roof light is not less than 900 mm from the allotmentboundary (c) the roof light is not less than 900 mm from the verticalprojectionof any separatingwall which extendsto the undersideof the roof covering (d)the roof light is not less than 1.8 m from any roof light in anotherbuildingon the allotment. 3 BCA REQUIREMENTS 3.4 NOTE: Where any of these limitationsare exceeded, the roof covering is regarded as combustible. Separating walls would therefore be required to project450mmabove the roof. 3.6 Smoke Alarms The BCA requiresthat all Class 1a buildingshave automaticsmoke alarmsinstalled. Smoke alarmsmust complywithAS 3786 and be connectedto mainspower. Alarmsshall be installedon or near the ceiling(at least one alarmper storey), locatedbetweeneach part of the dwellingcontainingbedroomsand the remainderof the dwelling. NOTE: The intention of smoke alarms is to detect smoke before it reaches sleeping occupants, wake them,andgivethemtimeto evacuateto safety. NOTE: Eaves soffit lining must be non-combustible but it is not required to be fire rated or have a fire resistance level. Normal fibre cement products are acceptable. Openings(doors,windows etc) in fire resisting externalwalls must be protected. The following are regardedas beingprotected:(a) self closingsolid core doors (b)non-openablefire windows (FRL - /60/ -) to habitablerooms. (c) maximum900 x 600 mm windows with steel frame and no openingsashesto non-habitablerooms. (Note: Can be permanentlyvented). (d)Translucenthollow glass blocks. MRTFC Class 1a - Design & Construction Manual 7 Stud width 4 STRUCTURAL REQUIREMENTS 4.1 (W) Stud depth (D) TimberMemberDesign Timbermembersizes for Class 1(a) buildingsshall be determinedin accordancewithAS 1684 -1999 ResidentialTimberFramedConstruction. Stud In separatingwalls and fire rated externalwalls the studs and platesshall also be the size determinedfrom AS 1684.The minimumsize of studs shall be 70 x 45 mm or 90 x 35 mm studs in loadbearingseparating walls. 70 x 35 mm studs can only be used in nonloadbearingseparatingwalls. C The stud spacingin separatingwalls and fire rated externalwalls shall not be greaterthan 600 mm. B E A A Timberspeciesshall have an average dry densityof not less than 450 kg/m3. 4 STRUCTURAL REQUIREMENTS E P (Note: Normalsoftwood, cypressand hardwood framingmaterialmeetsthis requirement). F Bottom plate 4.2 Noggings Noggingsshall be providedin all loadbearingwalls at a maximumspacingof 1350 mm. Noggingsmay be staggered(by up to the noggingdepth). NOTE: To achieve satisfactorysound performance in double stud and staggered stud walls, noggings between studs supporting linings to one dwelling must be kept clear of studs and nogging supporting the linings to the adjoiningdwelling(refer Figures 9 and19). 4.3 Notches,Cuts,Holes Wherever possible,notches,cuts and holes shouldbe avoidedin structuralmemberswithinfire rated walls. Wherethese cannotbe avoided,sizes and spacings shall be limitedto those inAS 1684 - 1999. FIGURE 3 - CUTS, NOTCHES AND HOLES. TABLE A CUTS, HOLES AND NOTCHES IN STUDS AND PLATES DESCRIPTION A LIMITS Distance between holes and/or notches in stud breadth Minimum 3 x D H Hole (studs and plates) Maximum 25 mm in wide face only C Notch into stud breadth Maximum 10 mm E Notch into stud depth • Maximum 20 mm at every fifth stud • Maximum 20 mm for diagonal bracing • Up to 25 mm for installation of bath • Not permitted where studs are designed as “not notched” F P 8 Distance between notches in stud depth Minimum 12 x B Trenches in plates 3 mm maximum MRTFC Class 1a - Design & Construction Manual 5 FIRE SEPARATION 5.1 Fire ResistanceLevel Separationwalls betweenClass 1 attacheddwellings, must be constructedto limit the spreadof fire and allow the occupantsto safelyevacuate. The level of fire resistancerequiredby the BCA is for the separating wall to remainstructurallyintactand not allow the passageof flame,heat, smoke and hot gases for a periodof at least 1 hour. This fire resistancelevel is expressedas FRL 60/60/60(or FRL - /60/60for nonloadbearing). WhereClass 1 buildingsare within900 mm of a side or rear boundary, or closerthan 1800 mm to another building(In SouthAustralia,within600 mm of boundaryor within1200 mm of anotherbuilding), externalwalls also requirea fire resistancelevel of FRL 60/60/60(or - /60/60for non-loadbearing). The FRL for an externalwall only requiresto be measured from the outside. To achieve the fire resistancelevel in timberframed walls, fire gradeliningsare fixed to studs with all joints,intersectionsand penetrationssealed. Liningmanufacturers(in associationwith the timber industry)have developedvarioussystemswhichhave been testedand certified by recognisedtesting authorities(CSIRO or BRANZ). FRL 60/60/60 separatingwalls have eithera singlelayer of 16 mm thick fire gradeplasterboardeach side, or a layer of 13 mm fire gradeplasterboardplus a layer of 6 mm fibre cementto both sides. (Manufacturer’s recommendationsfor fixing sheetsmust be strictly adheredto). FIRE SEPERATION 5 To ensurethe fire resistanceis maintainedat joints, intersectionsand penetrations,the variousbuilding practicesand detailscontainedin this publication shouldbe followed (refer Section7). MRTFC Class 1a - Design & Construction Manual 9 5.2 SolidTimberat Intersections Many of the constructiondetailsin this manual incorporateadditionalsolid timber(blockingor extra studs,joists,etc.) in lieu of the fire gradeliningto protectthe timberframeand maintainthe fire resistancelevel at intersectionsetc. This systemhas been developedto simplifyand speedup the constructionprocessby allowing all framingto be completedand roof installedbeforefixing plasterboard linings. NOTE: Whentimberburns,it chars relativelyslowly from the outside at a predictable rate. This allows additional,sacrificial timberto be used in lieu of fire gradelining, to protectstructural members. To maintainFRL 60/60/60at intersectionsa minimum of 45 mm thicknessof solid timber(minimumaverage dry densityof 450 kg/m3) is required. This is in additionto any structuralmemberwithinthe fire rated wall. NOTE: The timber used to maintain the FRL cannot carry out a structural function within the separating wall. It can however be used to support non-rated floors or partitions. No additional fixing is required (for ledgers etc.) other than required to support loads. Figure4 shows typicaljunctionswhere45 mm thicknesssolid timberis used in lieu of fire grade lining. NOTE: Any timber grade and species (hardwood, softwood, LVL) commonly used for framing has an average dry densityin excessof 450 kg/m3 and can be usedfor blocking. Separating walls (double studs or staggered studs) Fire grade linings Non-rated partition 5 FIRE SEPERATION 1 x 45 or 2 x 35 mm studs to maintain fire resistance where fire grade linings do not continue through intersection 4(a) - Typical intersections between separating wall and internal partition Separating walls (double studs or staggered studs) Fire grade linings Caulking Non-rated timber floor Additional 45 mm thick joist, ledger, trimmer or blocking to maintain fire resistance Nogging to support edge of lining Joist/bearer to support upper wall 4(b) - Typical intersections between separating wall and timber floor FIGURE 4 - TYPICAL JUNCTIONS WITH ADDITIONAL SOLID TIMBER 10 MRTFC Class 1a - Design & Construction Manual 5.3 StrengthenedJoints Wherethe intersectionbetweenthe fire gradeliningsis strengthenedby either:• 35 x 35 mm plasterer’s angle • intumescentsealeror • fibre cementliningcontinuedthroughjoint Then the thicknessof solid timberto maintain FRL 60/60/60can be reducedto 35 mm. Figure5 shows typicalintersectionswhichhave been strengthenedand allow the use the reducedtimber thickness. 35 mm x 35 mm plasterers’ angle Caulking Studs positioned to support angles Noggings or top plate to support edge of lining 5(a) - Using 35 x 35 mm Plasterer’s angles Intumescent sealant FIRE SEPERATION 5 Studs behind sealant Noggings on top plate 5(b) - Using intumescent sealant Fire grade plasterboard Caulking Fibre cement lining continuous through intersection Noggings at 600 mm maximum centres if studs are not at intersection 5(c) - Using continuous fibre cement lining FIGURE 5 - STRENGTHENED JOINTS MRTFC Class 1a - Design & Construction Manual 11 6 SOUND CONTROL 6.1 COMMENTARY: WeightedSoundReductionIndex(Rw) The BCA requiresthe weightedSoundReduction Index (Rw) and the resistanceto impactin separating walls as shown in Table B. TABLE B BCA REQUIREMENTS Rw AND SOUND IMPACT LEVELS FOR SEPARATING WALLS LOCATION IMPACT SOUND RESISTANCE Thereare two types of soundswhichneed to be controlled. Theseare from airbornesourcessuch as speech,musicalinstrumentsand loudspeakers and the other beingimpactsources,such as footstepsand the moving of furniture. Soundtransmissioncan be reducedby:• Rw LEVEL Increasingmass can be achieved by increasingliningthicknessor densityor using more layersof linings. • (b) All other separating walls. SOIL AND WASTE PIPES A waste pipe or other penetration that serves or passes through a separating wall between houses – (a) If the adjacent room is a habitable room (other than a kitchen); or Required 50 • Not Required 45 Not Required 45 SOUND CONTROL 6 • 12 Sealing/CaulkingVoids Soundleaks can easilyoccurat the periphery of walls and floors,or wherea hole is made for electricityor plumbingservices. To reducesoundleaks,all gaps in a wall or floor must be thoroughlycaulked, or sealed. 30 NOTE: The BCA requirements for sound control between dwellings listed above should only be regarded as the absolute minimum to meet statutory requirements. It is recommendedthat a minimum of Rw 50 be providedand resistanceto impactsoundbe considered in all separating walls. Rw 50 with impact resistance is considered necessary to reduce airborneand structure borne noise to an acceptable level. Test results for buildings or building elements with STC values in accordance with the 1979 version of AS 1276 remain valid. The STC value is the same as the Rw value. AvoidingRigidConnections Rigidconnectionsbetweenadjoining dwellingscan transmitsoundenergy. Where connectionsare requiredfor structure stabilityetc., resislientconnectorsshouldbe used. • (b) if the room is a kitchen or any other room. UsingAbsorptive Material Fillingthe cavity with absorptive insulation material(cellulosefibre, glass fibre or mineralwool) can reduceairborne transmissionsubstantially, especiallywhen the cavity is large. • Not Required UsingCavity Construction(Isolatingwall surfaces) One of the most effective ways of reducing soundtransmission(airborneand impact)is to isolatethe wall surfaces of adjoining dwellings. This is achieved throughthe use of doublestud or staggeredstud wall. SEPARATING WALLS (a) Between a bathroom, sanitary compartment, laundry or kitchen in one Class 1 building and a habitable room (other than a kitchen) in an adjoining Class 1 building. IncreasingMass BuildingLayout One of the simplestmeansof controlling noise is to distancenoise sourcesfrom sensitive receiving areas. Laundries,service shafts,stairs and other noisy areas in buildingsshouldbe locatedas far as possible from sensitive living or sleepingareas. Placingrelatively quiet areas such as bedroomsor loungeroomsnext to each other also helps to minimisethe noise reduction requiredfor occupantsatisfaction. Care is requiredin locatingthe windows to ensure they do not face noisy areas and that there is adequateseparationbetweenwindows in adjoiningdwellings. MRTFC Class 1a - Design & Construction Manual 6.2 Wall FramingOptions For separatingwalls betweendwellingsit is recommendedthat doublestud or staggeredstud systemsbe used (refer Figure6). Theseare the only systemswhichprovide adequateresistanceto impact soundas well as airbornesound. Two walls separated by cavity (minimum 20 mm recommended) Singlestud walls shouldonly be used in situations wheresoundcontrolis not critical,such as in spaces, below sub-floorsor betweengarages. Wheresuspendedfloorsin adjoiningunits are at differentlevels, it is recommendedthat only double stud wall systemsbe used (refer Figure13). Satisfactoryimpactsoundresistancecannotbe achieved with staggeredstud walls or singlestud walls (even with resilientchannels)wherefloorsare nonaligned. Note: The various wall systems and fire grade lining optionsare summarisedin tables C,D and E. Linings to be fixed in accordance with manufacturers recommendationsandas outlinedin Section8. Studs are not required to be in line 6(a) - Double stud walls Adjacent studs to align with opposite sides Lining fixed to every second stud 6(b) - Staggered stud walls SOUND CONTROL 6 Resilient channels or mounts when required for sound insulation 6(c) - Single stud walls FIGURE 6 - WALL FRAMING OPTIONS MRTFC Class 1a - Design & Construction Manual 13 To satisfy the BCA requirements and meet consumer expectations the following details and practices should be adopted. 7 CONSTRUCTION DETAILS AND BUILDING PRACTICE Additional joists 45 mm minimum thick to maintain fire resistence Additional 45 mm thick trimmer or blocking to maintain fire resistence Joists as required to transfer loads from separating wall to masonry Caulking Caulking Caulking Sawcut Sawcut Sawcut Solid timber as required to transfer loads from separating wall to masonry Bearer Termite barriers (through or over masonry wall) Joist Bearer Masonry wall minimum 90 mm wide with attached piers 7(a) - Masonry wall taken up to joists Additional joists 45 mm minimum thick Caulking Caulking Sawcut Sawcut Joists and bearers to transfer loads from separating wall to masonry Caulking Caulking Sawcut Sawcut Joist Minimum 45 mm thick blocking Bearer Bearer may be either sheeted with 2 x 13 mm fire grade plasterboard or additional 45 mm thick timber blocking 7(b) - Masonry wall taken up to bearers Nogging Caulking Joists, trimmer ledger 45 mm minimum thick Caulking Nogging CONSTRUCTION & DETAILS 7 Bearer 45 mm thick blocking or fire grade lining between bearers Note: All details suitable for double stud or staggered stud separating walls 7(c) - Separating wall supported off masonry wall FIGURE 7 - MASONRY SUB-FLOOR SEPARATING WALLS 14 MRTFC Class 1a - Design & Construction Manual 7.1 Sub-FloorSeparatingWalls Separatingwalls must be continuousfrom the ground to the undersideof a non-combustibleroof or 450 mm above a combustibleroof. Walls below suspended groundfloorsmay be masonry(refer Figure7) or timberframedwith fire gradelining(refer Figure8). Timberframedsub-floorseparatingwalls may be either loadbearingextensionsof the separatingwall above, or alternatively non-loadbearinginfill walls between structuralpiers. Solid timber or framing to transfer wall loads to sub-floor wall Caulking Additional 45 mm thick joist Sawcut Caulking 45 mm thick blocking Sawcut Joist Additional blocking (minimum 45 mm thick) Bearer Either 2 x 13 mm thick fire grade plasterboard or additional 45 mm thick timber to protect bearer Single stud wall between posts (termite resistant framing below termite barrier) DPC Structural post or pier (timber, brick or masonry) Timber sole plate Note: This detail only to be used where no termite hazard exists 8(a) - Single stud wall between concrete or masonry piers Minimum 45 mm thick blocking, ledger or trimmer Caulking Caulking Caulking Caulking Sawcut Sawcut Joist Joist supported off hangers or ledgers 1 x 16 mm fire grade plasterboard or 1 x 13 mm fire grade plasterboard plus 6 mm fibre cement to both sides 75 mm 7 CONSTRUCTION & DETAILS 45 mm minimum thick joists or ledger Solid timber to transfer wall loads to sub-floor wall 8(b) - Separating wall (double or staggered studs) supported off footing FIGURE 8 - TIMBER FRAMED SUB-FLOOR SEPARATING WALLS MRTFC Class 1a - Design & Construction Manual 15 7.2 DoubleStud SeparatingWalls Separatingwalls may be constructedwith two individualstud framedwalls (refer Figure9 and Table C). Note: Refer figure 11-13 for floor intersections and figure 14 for roof/ceiling intersections NOTE: Complete isolation of the two structural frames in double stud walls provides the best airborneandimpactsoundresistance. Intersectionsmust be constructedto maintainthe fire resistancelevel and soundperformance. The following typicaldetailsshow recommendedbuilding practicefor doublestud separatingwalls:- Fire grade linings Figure9 - Doublestud walls (typical) Acoustic insulation may be provided (either between studs in one leaf or in wall cavity) Figure10 - Two storey doublestud walls Figure11 - Intersectionsbetweensuspendedfloors and separatingwall Figure12 - Bearerssupportedin separatingwall Figure13 - Non-alignedfloors Nogging may be staggered for 2 layer linings or where single layer linings are fixed vertically Figure14 - Separatingwalls above ceilings Figure15 - Intersectionswith internalwalls Figure16 - Intersectionwith brick veneer external wall Figure17 - Non-alignedexternalwalls Figure18 - Intersectionwith lightweightclad externalwall. 5 - 10 mm gap below lining (refer manufacturer’s recommendation) gaps to be caulked 20 mm minimum cavity to achieve Rw listed in table C Overall width refer table C Opposing studs in the two leaves may be in-line or offset CONSTRUCTION & DETAILS 7 Studs 600 mm max c/s Lining options a. 6 mm fibre cement plus 13 mm fire grade plasterboard both sides (fibre cement may be inner or outer layer) Note: Refer figure 15-18 or wall intersections b.16 mm fire grade plasterboard to both sides (13 mm in non-load bearing walls) FIGURE 9 - DOUBLE STUD WALLS (FRL 60/60/60) 16 MRTFC Class 1a - Design & Construction Manual TABLE C DOUBLE STUD WALLS FRL 60/60/60 Fire Grade Linings One layer 16 mm fire grade to plasterboard both sides. (loadbearing or non-loadbearing walls) One layer 13 mm fire grade plasterboard to both sides. (non-loadbearing walls only) 6 mm fibre cement plus 13 mm fire grade plasterboard to both sides. (See Note 4) NOTES: Studs (minimum size) 90 x 35 mm @ 600 mm max. centres. 70 x 45 mm of 600 mm max. centres (See Note 3) 90 x 35 mm a 600 mm max.centres 70 x 35 mm at 600 mm max. centres 90 x 35 mm @ 600 mm max. centres 70 x 45 mm @ 600 mm max. centres. (70 x 35 mm in non-loadbearing walls) Insulation Nominal Rw (refer notes) 50 mm 53 - 55 Nil 47 50 mm 50 - 52 Overall Width (20 mm cavity) 232 mm 192 mm Nil 46 50 mm 53 - 55 Nil 45 50 mm 50 -52 Nil 45 50 mm 58 -61 Nil 53 - 54 50 mm 57 - 59 226 mm 186 mm 238 mm 198 mm Nil 51 - 52 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/m3. 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. CONSTRUCTION & DETAILS 7 MRTFC Class 1a - Design & Construction Manual 17 Nogging behind edge of lining Studs continuous for full 2 storey height Caulking Resilient structural connections at mid floor level Note: For load-bearing walls or where length of 2 storey wall exceeds 3.5 metres additional lateral restraint may be required 45 mm thick ledger Note: Isolating stairs from wall provides superior sound performance 10(a) - Studs continuous for two storeys Caulking Resilient structural connections at mid floor level Note: For load-bearing walls or where length of 2 storey wall exceeds 3.5 metres additional lateral restraint may be required Blocking or framing to transfer upper wall loads to lower wall Note: Isolating stairs from wall provides superior sound performance CONSTRUCTION & DETAILS 7 10(b) - Upper wall supported off lower wall FIGURE 10 - TWO STOREY DOUBLE STUD WALLS 18 MRTFC Class 1a - Design & Construction Manual Note: In all cases, floors must be able to collapse in the event of fire and leave the separating wall intact. Caulking Caulking Sawcut Joists to transfer load from upper wall to lower wall Sawcut Caulking Sawcut Caulking Sawcut Joist Additional 45 mm thick joists or ledgers to maintain fire resistence Joist hanger or angle Upper wall supported directly off lower walls Caulking Caulking Fibre cement may continue through Caulking Joist 45 mm thick or 35 mm if fibre cement continued through intersection Caulking Floor truss I beam etc. Top chord may be supported off ledger Joist hanger or angle Caulking Caulking 45 mm thick solid timber Fire grade linings (all layers) must continue through intersection or 45 mm thick solid timber provided to maintain fire resistence 11(a) - Joists paralled to separating walls 45 mm thick ledger 11(b) - Joists perpendicular to separating walls FIGURE 11- INTERSECTIONS BETWEEN SUSPENDED FLOOR AND SEPARATING WALLS MRTFC Class 1a - Design & Construction Manual 19 CONSTRUCTION & DETAILS 7 Note: Upper wall must not be supported off bearers Bottom plate upper wall Compressed mineral wool Top plate lower wall Bottom plate Studs each side of bearer to support wall plates (45 mm thick) 45 mm thick joists Nogging (45 mm thick) Bearer Bearer Compressed mineral wool Top plate lower wall Fire grade lining sealed against bearer Slope top of bearer to allow rotation in the event of collapse 12(a) - Section / Elevation Posts/joists directly below to support bearer 12(b) - Plan view FIGURE 12 - BEARERS SUPPORTED OFF SEPARATING WALL Caulking Sawcut Note: Any of the floor intersection details for double stud walls are suitable for non aligned floors (refer figure 11). Caulking Sawcut Additional 45 mm thick timber to maintain fire resistence CONSTRUCTION & DETAILS 7 Note: Staggered stud and single stud walls do not provide satisfactorily sound performance where floors are non-aligned. FIGURE 13 - NON-ALIGNED FLOORS 20 MRTFC Class 1a - Design & Construction Manual Cavity between top of wall and underside of roof to be filled with compressed fire resistant mineral wool Single stud wall Truss Note: Refer to truss manufacturers for minimum bearing requirements Ceiling Double stud or staggered stud walls Figure 14(a) - Single stud wall Notes: 1. Additional ledgers/battens may be required to support ceilings. 2. Top of wall cavity may need to be sealed to prevent moisture from entering cavity during construction. 3. These details are also suitable above staggered stud walls. Two nailed gable trusses. Vertical truss members at maximum 600 mm centres 70 mm minimum width between linings Nogging to support edge of lining Batten (where required) to support ceiling 45 mm thick ledger Fire grade linings as for separating wall Fire grade lining may continue through 14(b) - Separating wall continued up to roof Compressed fire resistant mineral wool between battens 7 Compressed mineral wool to fill irregularities between truss and wall 14(c) - Sheeted trusses FIGURE 14 - SEPARATING WALLS ABOVE CEILINGS MRTFC Class 1a - Design & Construction Manual 21 CONSTRUCTION & DETAILS Compressed fire resistant mineral wool between roof battens Nogging at 600 mm spacing where no studs at intersecting wall Fire grade lining continuous through joint 15(a) - Fire grade linings continuous Nogging at 600 mm spacing where no studs at intersecting wall Minimum 35 mm thick stud Fibre cement first layer continuous through joint 15(b) - First layer (fibre cement) continuous 2 x 35 mm or 1 x 45 mm studs to maintain fire resistence. 1 x 35 mm or 1 x 45 mm if joint reinforced with plasterers angle or intumescent sealant (refer figure 5) CONSTRUCTION & DETAILS 7 Additional studs to fix linings Additional stud 15(c) - Studs in intersecting wall used to maintain fire resistance FIGURE 15 - INTERSECTIONS WITH INTERNAL WALLS 22 MRTFC Class 1a - Design & Construction Manual Wall plate not to be continuous across separating wall Wall plate not to be continuous across separating wall Additional studs to support wall linings Additional studs to support wall linings Fire grade lining Fire grade lining 45 mm thick solid timber blocking Compressed mineral wool to fill cavity Vertical DPC Vertical DPC 16(a) - Cavity blocked with timber 16(b) - Cavity filled with mineral wool DPC and fire-stopping if required Wall plate not to be continuous across separating wall Fire grade linings continued through to brickwork 16(c) - Fire grade linings continued across cavity FIGURE 16 - INTERSECTION WITH BRICK VENEER EXTERNAL WALL See note Note: Although fire grade linings are not required in external walls, the linings would normally be extended to the next intersection or construction joint Fire grade lining dpc 7 Minimum 45 mm thick CONSTRUCTION & DETAILS Cavities blocked with mineral wool or solid timber 45 mm thick) FIGURE 17 - INTERSECTION WITH NON-ALIGNED EXTERNAL WALL MRTFC Class 1a - Design & Construction Manual 23 Cladding Mineral wool Breather type sarking Cladding Breather type sarking Minimum 45 mm thickstuds Note: Top and bottom plate to external wall not to continue across separating wall Additional studs to support wall linings Fire grade lining Compressed fire resistant mineral wool to fill any voids in external cladding (e.g. lapped weatherboards) CONSTRUCTION & DETAILS 7 18(a) - Non rated external wall FIGURE 18 - INTERSECTION WITH LIGHTWEIGHT CLAD EXTERNAL WALL 24 MRTFC Class 1a - Design & Construction Manual Cladding Fire grade lining Breather type sarking Cladding Breather type sarking Note: Any external cladding materials (e.g. Timber weatherboards) may be used over the top of fire grade linings in fire rated external walls 45 mm thick studs Additional studs to support wall linings Fire grade lining Fire grade lining Note: Top and bottom plate to external wall not to continue across separating wall CONSTRUCTION & DETAILS 7 Figure 18(b) - External wall FRL 60/60/60 (measured from outside only) MRTFC Class 1a - Design & Construction Manual 25 7.3 Staggered Stud SeparatingWalls Separatingwalls may be constructedusing a singletop and bottomplate (120 mm or 140 mm wide)with alternatestuds staggeredto align with oppositeedges. Fire gradeliningsare fixed to alternatestuds. (refer Figure19 and Table D). Note: Refer figures 20,21,22 & 24 for floor and ceiling intersections Full width top plate (refer table D) Isolationof the structuralframe(except for plates) provides satisfactoryresistanceto impactsoundas well as airbornesound. Fire grade linings NOTE: Staggered stud walls are not recommended for separating walls between units where floors are not aligned. Satisfactorysoundperformancecannot be achieved at floorintersections. Doublestudwalls are recommendedfor non-alignedfloors. Noggings kept clear of studs which support lining to adjoining dwelling The following typicaldetailsshow recommended buildingpracticefor staggeredstud separatingwalls to maintainfire resistanceand soundperformance:Figure19 - Staggeredstud walls (typical) 35 mm thick noggings on edge between alternate studs Figure20 - Two storey staggeredstud walls Figure21 - Intersectionsbetweensuspendedfloors and separatingwalls. Figure22 - Bearerssupportedoff separatingwall. Figure23 - Separatingwalls above ceilings. Full width bottom plate Figure24 - Intersectionswith internalwalls Caulking Figure25 - Intersectionwith brick veneer external wall. Figure26 - Non-alignedexternalwall. Figure27 - Intersectionwith lightweightclad externalwall. 5 - 10 mm gap below lining (refer manufacturer’s recommendation) gap to be caulked Overall width (refer table D) Nogging between alternate studs 7 CONSTRUCTION & DETAILS 300 mm 300 mm 600 mm Lining options a. 6mm fibre cement plus 13 mm fire grade plasterboard both sides (fibre cement may be inner or outer layer) Note: Figures 23, 25, 26 & 27 for wall intersections b. Single layer fire grade plasterboard both sides (16 mm for loadbearing walls, 13 mm for non-loadbearing walls) FIGURE 19 - STAGGERED STUD WALLS (FRL 60/60/60) 26 MRTFC Class 1a - Design & Construction Manual TABLE D STAGGERED STUD WALLS FRL 60/60/60 Fire Grade Linings Insulation One layer 16 mm fire grade to plasterboard both sides. (loadbearing or non-loadbearing walls) One layer 13 mm fire grade plasterboard to both sides. (non-loadbearing walls only) 6 mm fibre cement plus 13 mm fire grade plasterboard to both sides. (See Note 5) Nominal Rw Studs Top and (refer notes) (minimum size) bottom plates Overall Width 50 mm 49 - 51 90 x 35 140 x 35 172 mm Nil less than 45 90 x 35 120 x 35 (see Note 2) 152 mm less than 45 70 x 45 120 x 35 152 mm 50 mm 45 - 47 90 x 35 or 70 x 35 120 x 35 146mm Nil less than 45 (see Note 4) 50 mm 56 - 57 90 x 25 140 x 35 178 mm Nil 50 120 x 35 (see Note 2) 158 mm 50 mm 55 - 56 120 x 35 158 mm Nil 49 70 x 45 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 mm max. 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/m3. Different types of insulation will give different 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. Nogging behind edge of lining Studs continuous for 2 storeys Resilient structural connections at mid floor level Full width top and bottom plates provide lateral restraints Refer figure 21 & 22 for intersection details Note: Isolating stairs from wall provides superior sound performance 20(a) Studs continuous for 2 storeys 20(b) Upper wall supported by lower wall FIGURE 20 - TWO STOREY STAGGERED STUD WALLS MRTFC Class 1a - Design & Construction Manual 27 7 CONSTRUCTION & DETAILS Note: For loadbearing walls or where length of two storey wall exceeds 3.5 metres additional lateral restraint may be required Joists/blocking as necessary to support wall above Joists/blocking as necessary to support wall above Caulking Caulking Caulking Sawcut Fibre cement first layer may continue through joint Sawcut Additional 45 mm thick joist or ledger (35 mm if reinforced) to maintain fire resistance 45 mm thick joists (35 mm if reinforced) to maintain fire resistance Upper wall supported directly off lower wall Fibre cement first layer may continue through joint Caulking Floor trusses may be supported by top chord off ledger Caulking Caulking Sawcut Sawcut Hanger or angle 45 mm thick solid timber (35 mm if reinforced or fibre cement continuous) 21(a) - Joists paralled to separating wall 45 mm thick or 35 mm thick if joint reinforced or fibre cement sheet continued through (refer figure 5) 21(b) - Joists perpendicular to separating wall Note: Where ‘I’ beams or floor trusses are used, either fire grade linings (all layers) must continue through intersection or substituted with solid timber to maintain fire resistance. FIGURE 21 - INTERSECTIONS BETWEEN SUSPENDED FLOORS ON SEPARATING WALL CONSTRUCTION & DETAILS 7 28 MRTFC Class 1a - Design & Construction Manual Blocking (additional joists) to transfer upper wall loads to lower wall (not supported off bearer) Upper wall supported directly off lower wall Bottom plate 45 mm thick joists Caulking Sawcut Caulking Additional joist 45 mm thick Top plate Seal around bearer Compressed mineral wool Fire grade linings Fire grade linings Slope tops of bearers to allow bearers to rotate in the event of collapse 22(b) - Timber blocking to transfer wall loads Bearers supported off additional studs (posts) 22(a) - Upper wall supported off lower wall Notes: 1. Bearers must NOT be continuous through wall 2. Upper wall must NOT be supported off bearers Studs to support top plate and wall above Bearers supported off additional studs (posts) Seal around bearer Studs to support top plate and wall above CONSTRUCTION & DETAILS 7 22(c) - Plan views FIGURE 22 - BEARER SUPPORTED OFF STAGGERED STUD WALL MRTFC Class 1a - Design & Construction Manual 29 45 mm thickness (35 mm if reinforced) Gap Gap Additional studs to support linings 1 x 45 mm or 2 x 35 mm joists Gap Additional studs to support linings Gap 7 CONSTRUCTION & DETAILS 45 mm minimum thickness (35 mm if joint reinforced) FIGURE 23 - INTERSECTION WITH INTERNAL WALLS 30 MRTFC Class 1a - Design & Construction Manual Cavity between top of wall and underside of roof to be filled with compressed fire resistant mineral wool 45 mm thick ledger to support ceiling and trusses. Fire-rated wall Truss Use truss boots as required to support trusses on ledger Nogging behind edge of linings Note: Single stud walls or sheeted trusses may be used in ceiling spaces above staggered stud separating walls. Refer figure 14 for typical details. FIGURE 24 - SEPARATING WALLS ABOVE CEILINGS Top plate and bottom plate must not be continued over separating wall Additional studs to support wall linings CONSTRUCTION & DETAILS 7 Cavity to be blocked with either fire resistant mineral wool, solid timber or fire grade linings continued to masonry (as for double stud walls - figure 16) FIGURE 25 - INTERSECTION WITH EXTERNAL BRICK VENEER WALL MRTFC Class 1a - Design & Construction Manual 31 Note: Although fire grade lining is not required in external walls, the linings would normally be extended to the next intersection See note Additional stud to support lining Compressed fire resistant mineral wool and d.p.c. FIGURE 26 - INTERSECTION WITH NON-ALIGNED EXTERNAL WALLS Cladding Mineral wool Breather type sarking 7 Cladding Additional studs to support wall linings fire resistant mineral wool to fill voids in external cladding CONSTRUCTION & DETAILS Breather type sarking Top and bottom plate to external wall must not continue across separating wall Note: External wall may be fire rated (from the outside) with continuous fire grade lining inside cladding and sarking FIGURE 27 - INTERSECTION WITH LIGHTWEIGHT CLAD EXTERNAL WALLS 32 MRTFC Class 1a - Design & Construction Manual TABLE E SINGLE STUD WALLS FRL 60/60/60 Fire Grade Linings One layer 16 mm fire grade to plasterboard both sides. (13 mm in non-loadbearing walls) 6 mm fibre cement plus 13 mm fire grade plasterboard to both sides. NOTE: Fixing Insulation Resilient channels or mount to one side 50 Nominal Rw Studs (refer notes) (minimum size) 49 90 x 35 Overall Width 135 mm (129 mm for 13 mm lining) Nil less than 45 Furring channels with resilient mounted clips to one side 50 50 Nil less than 45 Direct to studs Nil to filled cavity less than 45 90 x 35 122 mm (116 mm for 13 mm lining) Direct to studs Nil 47 - 49 90 x 35 128 mm Nil less than 45 70 x 45 108 mm 90 x 35 157 mm (151 mm for 13 mm lining) 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/m3. 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. 7.4 SingleStud SeparatingWalls Wherenoise reductionis not requiredby the BCA (eg. BetweenClass 10 a garagesor carports)or in situations wheresoundtransmissionis less critical(eg. In subfloor and ceilingspaces),singlestud framedseparating walls may be used. (referTable E). Note: An acceptablelevel of sound transmissionloss can only be achieved in single stud walls with the use of resilient channels or resiliently mounted furring channels. These systems however are only recommended for single storey, single room applications (e.g. wet areas) because sound performancecannotbe maintainedat intersections. CONSTRUCTION & DETAILS 7 MRTFC Class 1a - Design & Construction Manual 33 7.5 ExternalWalls Externalwalls within900 mm of a side or near boundaryor closerthan 1800 mm to anotherbuilding are requiredto be FRL 60/60/60( -/60/60if nonloadbearing). (ReferFigure2) This fire resistance level needsonly to be attainedfrom the outside. Compressed mineral wool 45 mm thick blocking or fire grade lining taken up to roofing (where no eaves lining provided) FRL 60/60/60externalwalls can be either:• Brickveneer (minimum90 mm thick)brickswith any rated or non-ratedinternallinings. • 2 x 13 mm fire gradeplasterboardto externalface covered by waterproofcladding(may be combustiblematerial).Any rated or non-rated internallining • 1 x 16 mm wet area fire gradeplasterboardto externalface covered by waterproofcladdingfixed to verticalor horizontalbattensat 600 mm centres. 10 mm standardplasterboardinternallining. • Any FRL 60/60/60wall systems(referTables C, D and E) with fire gradeliningto both sides,with externalface covered by waterproofcladding(may be combustiblematerial). Non rated internal linings Note: Fire rating needs only to be from the outside Cladding Breather type sarking Fire grade lining FIGURE 28 - FIRE GRADE LINING OR BLOCKING CONTINUED UP TO ROOF Fire rated wall to extendup to non-combustibleroofing or non-combustibleeaves lining(refer Figure28 & 29). Compressed fire resistant mineral wool NOTE: Eaves linings are required to be noncombustiblebut not fire rated.Fibre cementproducts satisfythisrequirement. Detailingof intersectionsbetweenfire rated external walls and separatingwalls is exactlythe same as for non-ratedexternalwalls. (Fire resistanceof separating wall to be effectively continuedthroughexternalwall and any associatedcavity) (refer Figures17,18,25and 27). NOTE: Suspendedfloors may be supporteddirectly off rated or non-rated external walls. There is no requirement for floors to collapse away from externalwallsin the eventof fire. CONSTRUCTION & DETAILS 7 Separatingwalls must effectively extendthroughany void in ceilingsand eaves (refer Figure30). Wherefloorsare non-alignedor wherea singlestorey dwellingadjoinsa two storey dwelling,the separating wall and externalwall above the lower roof shall be as shown on Figure31. The separatingwall between dwellingsor betweendwellingand ceilingspace shall be FRL 60/60/60from both sides. The externalwall above the lower roof requiresFRL 60/60/60measured from the outsideonly. ( - /60/60for non-loadbearing walls). 34 45 mm thick blocking where fire grade lining not taken up to roofing Non rated internal linings Non combustible eaves lining (e.g. Fibre cement) Masonry 90 mm minimum thickness provides FRL 60/60/60 Note: Floor may be supported within fire rated external wall FIGURE 29 - FIRE RATED WALL (MASONRY OR FIRE GRADE LINING) TO NON-COMBUSTIBLE EAVES LINING MRTFC Class 1a - Design & Construction Manual Cavity between top of wall and underside of roofing to be filled with compressed fire resistant mineral wool Fire grade lining, and framing to extend through eaves Fire rated separating wall extended to underside of roofing Non fire-rated ceiling Non-combustible eaves lining Fire-rated separating wall Fire rated separating wall to be continued through timber wall and cavity (refer figure 16, 17, 18, 25 & 27) FIGURE 30 EXTENDING SEPARATING WALL THROUGH EAVES Fire grade lining Breather type sarking External cladding Note: Internal fire grade linings may not be necessary above roof but are generally continued up to ceiling Note: The external wall above a lower roof to have FRL 60/60/60 measured from the outside Flashing 45 mm thick blocking or ledger Mineral wool between battens Fire grade linings to separate unit from ceiling space Caulking CONSTRUCTION & DETAILS 7 Ledger to support ceiling Sawcut FIGURE 31 EXTERNAL WALL ABOVE LOWER ROOF MRTFC Class 1a - Design & Construction Manual 35 7.6 Plumbingand ElectricalServices The installationof plumbingor electricalservicesin separatingwalls have the potentialto reducethe fire resistanceand soundperformance. Wherepossible these servicesshouldnot be locatedwithinfire resistantwalls (ie. placedin adjoiningpartitions, ducts,or over the face of fire gradelinings(behind battenedout false wall). 300 mm min. 300 mm min. NOTE: Where plumbing services are required on noise sensitive walls, it is recommendedthat a false wall be built in front of the fire and sound-rated wall andthe plumbingbe placedintothisfalsewall. Whereserviceswithinseparatingwalls cannotbe avoided,the integrity of the wall must be maintained for both fire resistanceand soundinsulation. The following practicesshouldbe adopted:- Not more than one electrical recess in each wall face between any two studs (a) All holes,gaps or other irregularitiesassociated with penetrationsthroughfire-ratedelementsmust be sealedor must seal duringa fire. (b) Plumbingfittingsand/orelectricaloutletsshould preferablynot be back to back (ie. penetrateonly one face betweentwo studs). Gap between baffle and opposite studs in staggered stud walls FIGURE 32 BAFFLE BETWEEN ELECTRICAL OUTLETS OR SWITCHES (c) Electricaloutletswhichare back to back, should have eitherfire rated boxes (with intumescent backing)or be installedwith 16 mm thick fire gradeplasterboardbaffle extending300 mm above and below fittings(refer Figure32). 16 mm fire grade plasterboard baffle (d) Back to back plumbingpenetrationsshouldbe separatedby a 16 mm fire gradeplasterboard baffle extending300 mm above and 300 mm below penetration. 50 mm thick acoustic insulationshouldalso be installed(refer Figure 33). (e) Penetrationsfor servicesshouldbe kept a minimumof 50 mm from studs. Acoustic insulation CONSTRUCTION & DETAILS 7 Timber support battens 50 mm minimum Acoustic insulation between plumbing fixtures and fittings 300 mm Wet area sealant (h) Baths,shower bases,sinks,basinsmust not be recessedinto fire rated walls. Fire gradelinings must be continuousbehindfixtures(refer Figure 34). NOTE: Plastic pipes and fittings generally have bettersoundperformancethanmetal. Wet area sealant 16 mm fire grade plasterboard baffle (f) Pipes must not be fixed to linings. (g) Pipes shouldbe supportedoff battensbetween studs or kept clear of studs with resilientmounts). 16 mm fire grade plasterboard baffle Resilient mounts 300 mm Fire grade linings Timber battens FIGURE 33 - BAFFLE AND INSULATION BETWEEN PLUMBING OUTLETS 36 MRTFC Class 1a - Design & Construction Manual Void created by battens can be used for services Fire grade lining (e.g. 16 mm fire grade plasterboard) Lining board suitable for wet areas Timber batten Timber support batten fixed to studs Edge of bath/ shower not to be recessed into fire-rated wall 34(a) - Edge of bath Fire grade linings (e.g. 6 mm fibre cement plus 13 mm fire grade plasterboard) Lining board suitable for wet areas Vanity or kitchen unit not to be recessed into fire-rated wall Timber support batten fixed to studs 34(b) - Vanity or kitchen bench Lining board suitable for wet areas Fire grade linings CONSTRUCTION & DETAILS 7 Flashing fixed to face of rated wall Caulking to 5-10 mm gap 34(c) - Wet area floors FIGURE 34 - WET AREA INSTALLATION MRTFC Class 1a - Design & Construction Manual 37 7.7 BoxedGutters Figure35 shows typicaldetailsfor boxed guttersat separatingwalls. 45 mm thick blocking between trusses Bottom chords extended (refer truss manufacturer) 35(a) - Roof framing on top of separating wall (not to be continuous) Hanger (truss boot) 45 mm thick ledger 35(b) - Roof framing supported off hangers and ledgers Breather type sarking Cladding Flashing Note: Bottom chord extended to box gutter width (refer truss manufacturer) CONSTRUCTION & DETAILS 7 Fire grade linings Hanger (truss boot) 45 mm thick ledger 35(c) - Box gutter at parapet or for lower roof FIGURE 35 - BOX GUTTERS 38 MRTFC Class 1a - Design & Construction Manual 8 FIXINGS OF LININGS To achieve FRL 60/60/60in separatingwalls the following fire gradeliningsand required:(a) LoadbearingWalls - 1 x 16 mm fire gradeplasterboardto both faces or - 1 x 13 mm fire gradeplasterboardplus 1 x 6 mm fibre cementto both faces (eithersheet fixed first) A gap of between5 and 10 mm shall be kept at the bottomof fire gradeliningsat floor level. Gap to be caulked with a fire resistantsealer. NOTE: Caulking should generally be flexible to allow for timber movement. Non-flexible caulking (eg. Vermiculite plaster) may be used to seal gaps between lining and concrete floors where seasoned framingis used. (b) Non-LoadbearingWalls - 1 x 13 mm fire gradeplasterboardto both faces (or eitherof the loadbearingoptions). Differentliningmanufacturershave different requirementsfor nail sizes and spacings. Liningsmust be installedstrictlyin accordancewith manufacturer’s instructions. Internaland externalcornerjunctionsmust be arranged to provide supportto both liningboards.Additional studs or noggingsmay be required. All verticalbutt jointsshall be on studs with joints staggered. (ie. sheetson same face as well as sheetson the oppositeface must not have verticaljointson the same stud). NOTE: Staggered nogging may be used for dual layer systems, or where single layers are fixed verticallywithno horizontaljoints. Wheremultiplelayer liningsare used, horizontaland verticaljointsshall be staggered. Sheetscan be fixed horizontally, verticallyor a mixtureof both. The fibre cementsheetsmay be eitherthe first or secondlayer. NOTE: In FRL 60/60/60systemsfibre cement sheets maybe eitherfirst or secondlayer. At internalwall junctionsand at intersectionsbetween separatingwalls and ceilings,any gaps betweenlinings shall be sealedwith flexible fire resistantsealer. NOTE: (ReferFigure 4 for the use of timberblocking and Figure 5 for strengthening of joints with either intumescent putty, plasterer’s angle or continuous linings. FIXING OF LININGS 8 MRTFC Class 1a - Design & Construction Manual 39 Studs at 600 mm centres Vertical joints staggered Nail spacings to manufacturers’ requirements 36(a) - Single layer fire grade plasterboard fixed horizontally Note: Vertical joints on opposite faces to be staggered (i.e. Not on the same stud) Studs at 600 mm centres Joints centred on stud Nail spacings to manufacturers’ requirements 36(b) - Single layer fire grade plasterboard fixed vertically Vertical joints staggered Nail spacings to manufacturers’ requirements 8 Nail spacings to manufacturers’ requirements FIXING OF LININGS 36(c) - Fibre cement in conjunction with fire grade plasterboard FIGURE 36 - FIXING OF LININGS 40 MRTFC Class 1a - Design & Construction Manual MULTI-RESIDENTIAL TIMBER FRAMED CONSTRUCTION For informationregarding MRTFCpleasecontact: New South Wales - TDA Timber Development Association of NSW 13-29 Nichols Street, Surrey Hills New South Wales 2010 Telephone (02) 9360 3088 Fax (02) 9360 3464 Queensland - TRADAC Timber Research And Development Advisory Council 500 Brunswick Street, Fortitude Valley Queensland 4006 Telephone (07) 3358 1400 Fax (07) 3358 1411 South Australia - TDA Timber Development Association of South Australia 113 Anzac Highway, Ashford South Australia 5035 Telephone (08) 8297 0044 Fax (08) 8297 2772 Victoria - TAC Timber Advisory Centre 180 Whitehorse Road, Blackburn Victoria 3130 Telephone (03) 9877 2011 Members of the National Timber Development Council ATIF - Australian Timber Importers Federation Fax (03) 9877 6663 FIAT - Forest Industries Association of Tasmania Western Australia - TAC FIFWA - Forest Industries Federation (Western Australia) Inc. FPA - New South Wales Forest Products Association Ltd. FWPRDC - Forest & Wood Products Reseach & Development Corporation Timber Advisory Centre of Western Australia 55 Salvado Road, Subiaco Western Australia 6008 Telephone (08) 9380 4411 Fax (08) 9380 4477 NAFI - National Association of Forest Industries PA - Pine Australia Ltd. Tasmania - TTPB PAA - Plywood Association of Australia Ltd. Tasmanian Timber Promotion Board Suite 22, 11 Morrison Street, Hobart, Tasmania 7000 Phone (03) 6224 1033 QTB - Queensland Timber Board TDA (NSW) - Timber Development Association (New South Wales) Ltd. Fax (03) 6224 1030 TDA (SA) - Timber Development Association (South Australia) Inc. Plywood Association of Australia TPC - Timber Promotion Council of Victoria 3 Dunlop Street, Newstead Queensland 4006 Phone (07) 3854 1228 TRADAC - Timber Research and Development Advisory Council (Qld) VAFI - Victorian Association of Forest Industries Fax (07) 3252 4769 Pine Australia FOREST&WOODPRODUCTS 830 High Street, Kew East Victoria 3102 Phone (Free Call) 1800 007 463 RESEARCH & DEVELOPMENT CORPORATION This publication is a joint venture between the National Timber Development Council and the Forest and Wood Products Research and Development Corporation. The FWPRDC is jointly funded by the Commonwealth Government and the Australian forest and wood products industry. © FWPRDC 2000 , Printed June 2000 Fax (03) 9859 2466 web www.timber.org.au/mrtfc