AS 1684.2:2021


Residential timber-framed construction, Part 2: Non-cyclonic areas

Published by Standards Australia, 06/25/2021


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AS 1684.2, 4th, 2021 – Residential timber-framed construction, Part 2: Non-cyclonic areas

AS 1684.2 specifies requirements for building practice and the selection, placement and fixing
of the various structural elements used in the construction of timber-framed Class 1 and Class 10 buildings as defined by the National Construction Code and within the limitations given in Clause 1.4. The provisions of this Standard also apply to alterations and additions to such buildings.

This Standard also provides building practice and procedures that assist in the correct specification and determination of timber members, bracing and connections, thereby minimizing the risk of creating an environment that may adversely affect the ultimate performance of the structure.

This Standard may also be applicable to the design and construction of other classes of buildings where the design criteria, loadings and other parameters applicable to those classes of building are within the limitations of this Standard.

NOTE 1: Refer to AS 1684.1 for details of design criteria, loadings and other parameters.
NOTE 2: While this Standard may be used to design Class 10 buildings, less conservative levels of design for this building class may be permitted by building regulations and other Australian Standards.
NOTE 3: Advisory information for the construction and specifications of timber stairs, handrails and balustrades is provided in FWPA’s Design Guide 8, see Bibliography.

This is Part 2 of a series of Standards for residential timber-framed construction. The Standards in the series are as follows:

AS 1684.1, Residential timber-framed construction, Part 1: Design criteria
AS 1684.2, Residential timber-framed construction, Part 2: Non-cyclonic areas
AS 1684.3, Residential timber-framed construction, Part 3: Cyclonic areas
AS 1684.4, Residential timber-framed construction, Part 4: Simplified — Non-cyclonic areas

General Product Information:

Committee TM-010
Purchase Note All current amendments available at time of purchase are included with the purchase of this document
Document Type PDF
ISBN 978 1 76113 389 3
Pages 316
Document Language English
Publisher Standards Australia
Status Current


Table of cotents

1 Scope and general
1.1 Scope and application
1.1.1 Scope
1.1.2 Application
1.2 Normative references
1.3 Terms and definitions
1.4 Limitations
1.4.1 General
1.4.2 Wind classification
1.4.3 Plan
1.4.4 Number of storeys of timber framing
1.4.5 Width
1.4.6 Wall height
1.4.7 Roof pitch
1.4.8 Spacing of bracing
1.4.9 Roof types
1.4.10 Building masses
1.5 Design criteria
1.6 Forces on buildings
1.7 Load paths — Offsets and cantilevers
1.8 Durability
1.9 Dimensions
1.10 Bearing
1.11 Stress grades
1.12 Engineered timber products and engineered wood products (EWPs)
1.13 Size tolerances
1.14 Alternative timber dimensions
1.15 Steel grade and corrosion protection
1.16 Requirements for design using this Standard
1.17 Interpolation
1.18 Alternative methods and materials
2 Framing members
2.1 General
2.2 Terminology of framing members
2.3 Vertical lamination
2.3.1 Vertical nail lamination
2.3.2 Lamination of spaced ring beams
2.4 Stud lamination
2.5 Horizontal nail lamination — Wall plates only
2.6 Load width and area supported
2.6.1 General
2.6.2 Floor load width (FLW)
2.6.3 Ceiling load width (CLW)
2.6.4 Roof load width (RLW)
2.6.5 Area supported
3 Substructure
3.1 General
3.2 Site preparation and drainage
3.2.1 General
3.2.2 Site clearing
3.2.3 Site drainage
3.3 Ground clearance and subfloor ventilation
3.4 Durability
3.4.1 Termite management
3.4.2 Species selection
3.5 Substructure bracing
3.6 Subfloor supports
3.6.1 General
3.6.2 Soil classification
3.6.3 Procedure
3.6.4 Determination of vertical gravity loads General Permanent (dead) loads (G) Live loads (Q)
3.6.5 Determination of total vertical gravity load combination for footings
3.6.6 Footing size or bearing area
3.7 Footings and supports for wind classifications N1 and N2
3.7.1 General
3.7.2 Simplified footing classification
3.7.3 Stumps and posts
3.7.4 Footing type support limitations (load widths × bearer spans)
4 Floor framing
4.1 General
4.1.1 Application
4.1.2 Materials
4.1.3 Framing configurations
4.1.4 Weatherproofing
4.1.5 Shrinkage
4.1.6 Cuts, holes and notches in bearers and joists
4.2 Building practice
4.2.1 Bearers General Fixing of bearers to supports Built-up bearers Double bearers (spaced bearers)
4.2.2 Joists General Location of joists Deep joists Fixing of joists to bearers or lower wall plates
4.3 Member sizes
4.3.1 Bearers Bearers supporting loadbearing walls Bearers supporting floor loads only Bearers in lower storey supporting upper storey floor loads Bearers supporting gable or skillion end walls Single or upper storey bearers supporting loadbearing walls at right angles to their span Bearers supporting roof point loads Bearers supporting decks more than 1.0 m off the ground
4.3.2 Floor joists General Floor joists supporting non-loadbearing gable or skillion end walls Floor joists supporting loadbearing walls at right angles to joists Single or upper storey floor joists supporting roof point loads and loadbearing walls parallel to joists Openings in floors Joists supporting decks more than 1.0 m off the ground
5 Flooring and decking
5.1 General
5.2 Platform floors
5.3 Fitted strip floors (cut-in floors) direct to joists
5.4 Expansion joints in strip floors direct to joists
5.5 Laying and fixing strip and sheet flooring direct to joists
5.5.1 Structural strip flooring — Laying
5.5.2 Structural strip flooring — Cramping and fixing General Fixing
5.5.3 Structural plywood flooring — Laying and fixing General Laying Fixing
5.5.4 Structural particleboard flooring — Laying and fixing General Laying Fixing
5.6 Wet area floors
5.7 Joist spacing — Flooring
5.8 Decking
6 Wall framing
6.1 General
6.1.1 Application
6.1.2 Wall frame members
6.1.3 Bracing
6.2 Building practice
6.2.1 Studs Straightening of studs (crippling) Common studs Wall junctions Notching, trenching and holes in studs and plates Noggings
6.2.2 Plates General Bottom plates Stiffening of top plates Joints in top plates and ring beams
6.2.3 Openings
6.2.4 Framing around chimneys and flues
6.2.5 Lateral support for non-loadbearing walls External walls Internal walls — Trussed roofs
6.3 Member sizes
6.3.1 General
6.3.2 Wall studs Common studs Studs supporting concentrated loads Jamb studs (studs at sides of openings) Internal loadbearing wall studs Gable or skillion end and non-loadbearing external wall studs Mullions Concentrated loads on non-loadbearing internal walls
6.3.3 Bottom plates
6.3.4 Top plates
6.3.5 Studs, plates and noggings in non-loadbearing internal walls
6.3.6 Lintels and ring beams General Lintels and ring beams in loadbearing walls Lintels or ring beams in gable end walls not required to transfer tie-down Lintels or ring beams supporting concentrated roof loads Lintels in non-loadbearing walls Windowsill, lintel and ring beam trimmers
6.3.7 Verandah beams (plates)
6.3.8 Posts supporting roof and/or floor loads
7 Roof framing
7.1 General
7.1.1 Application
7.1.2 Types of roofs and limitations General Coupled roof Non-coupled roof Trussed roof
7.2 Building practice
7.2.1 Ceilings
7.2.2 Construction loads on ceiling framing
7.2.3 Ceiling battens
7.2.4 Ceiling joists General Splices and joints in coupled roof Connection to hanging beams Trimming around openings Platforms in roof spaces
7.2.5 Hanging beams General End support of hanging beams
7.2.6 Counter beams General Intersection of hanging and counter beams
7.2.7 Combined strutting/hanging beams
7.2.8 Combined strutting/counter beams
7.2.9 Strutting beams
7.2.10 Underpurlins General Joints in underpurlins Cantilevered underpurlins Support of underpurlins
7.2.11 Rafters General Birdsmouthing
7.2.12 Ridgeboards General Joints in ridgeboards
7.2.13 Hip and valley rafters
7.2.14 Scotch valleys
7.2.15 Roof strutting Roof struts Tied and braced strut system Fan struts Opposing struts
7.2.16 Collar ties
7.2.17 Hip ends
7.2.18 Alternative support systems
7.2.19 Non-coupled roofs General Ridge and intermediate beams
7.2.20 Roof battens
7.2.21 Trussed roofs General Structural fascias Truss layout Support of trusses
7.2.22 Bracing for raftered and trussed roofs
7.2.23 Fixing of ceiling framing to internal bracing walls
7.2.24 Eaves construction General Boxed eaves
7.2.25 Gable or verge construction General Open gables Boxed gables
7.2.26 Lateral restraint of hanging, strutting, strutting/hanging beams, and similar members
7.2.27 Framing around chimneys and flues
7.3 Member sizes
7.3.1 General
7.3.2 Ceiling battens
7.3.3 Ceiling lining and non-trafficable roof decking General Tongued and grooved non-trafficable roof decking Structural plywood for non-trafficable roof decking
7.3.4 Loads on ceilings
7.3.5 Binders
7.3.6 Ceiling joists
7.3.7 Hanging beams
7.3.8 Counter beams
7.3.9 Combined strutting/hanging beams
7.3.10 Combined counter/strutting beams
7.3.11 Strutting beams
7.3.12 Underpurlins
7.3.13 Rafters and purlins General Rafter overhangs Birdsmouthed and non-birdsmouthed rafters Dressed rafters
7.3.14 Ridge or intermediate beams — Cathedral, skillion or similar roofs
7.3.15 Roof battens
7.3.16 Cantilevered gable ends
7.3.17 Other members or components
8 Racking and shear forces (bracing)
8.1 General
8.2 Temporary bracing
8.3 Wall and subfloor bracing
8.3.1 General
8.3.2 Wind pressure on the building
8.3.3 Area of elevation
8.3.4 Racking force
8.3.5 Subfloor bracing General Braced and cantilevered timber or concrete stumps Soil classification reduction factor Braced timber stumps Timber braces on concrete, masonry or timber columns Cantilevered stumps in concrete or soil backfill Bracing columns Unreinforced masonry bracing Spacing of bracing in lower storey of two storey construction or the subfloor of single or two storey construction
8.3.6 Wall bracing General Nominal wall bracing Structural wall bracing Wall capacity and height modification Length and capacity for plywood bracing walls Location and distribution of bracing Spacing of bracing walls in single storey or upper storey of two storey construction External bracing walls under the ends of eaves Fixing of top of bracing walls Fixing of bottom of bracing walls
8.3.7 Roof bracing Pitched roofs (coupled and non-coupled roofs) Gable roofs (including cathedral roofs) for wind classifications up to N2 Trussed roofs
9 Fixings and tie-down design
9.1 General
9.2 General connection requirements
9.2.1 General
9.2.2 Straps, bolts, screws, coach screws and framing anchors
9.2.3 Steel washers
9.2.4 Drilling for bolts
9.2.5 Drilling for coach screws
9.2.6 Screw and coach screw penetration
9.2.7 Framing anchor and strap nails
9.2.8 Joining of top plates and ring beam
9.2.9 Tie-down of members joined over supports
9.3 Procedure flow chart
9.4 Nominal and specific fixing requirements
9.5 Nominal fixings (minimum fixings)
9.6 Specific tie-down fixings
9.6.1 General
9.6.2 Uplift load width (ULW)
9.6.3 Application
9.6.4 Wind uplift forces
9.6.5 Joint group
9.7 Shear forces
9.7.1 General
9.7.2 Bottom plate to concrete slab
9.7.3 Floor joists to bearers/walls
9.7.4 Bearers to supports
9.7.5 Shear forces on joists and bearers
9.7.6 Shear forces on external non-loadbearing walls
Appendix A
A.1 Mass of roof and ceiling components
A.2 Examples — Determination of roof mass
Appendix B
B.1 Durability
B.2 Natural durability
B.3 Hazard level
B.4 Preservative treatment
B.5 Weathering
B.6 Service life
B.7 Specific durability design
Appendix C
C.1 Interpolation
C.2 Example — Span and overhang
Appendix D
D.1 General
D.2 Foundation bearing area
D.3 Even distribution of bracing
D.4 Shear force
D.4.1 Example 1 — Floor joists
D.4.2 Example 2 — Bearers to stumps
Appendix E
E.1 Moisture content
E.2 Dimensional stability
E.3 Allowance for shrinkage
Appendix F
Appendix G
G.1 General
G.2 Notes to the Table
G.2.1 Column 1 — Standard trade name
G.2.2 Column 2 — Botanical name
G.2.3 Column 3 — Strength group
G.2.4 Column 4 — Joint group
G.2.5 Column 5 — Density
G.2.6 Column 6 — Hardness
G.2.7 Column 7 — Toughness
G.2.8 Column 8 — Tangential shrinkage
G.2.9 Column 9 — Unit tangential movement (%)
G.2.10 Column 10 — Natural durability class of heartwood
G.2.11 Column 11 — Lyctid susceptibility of sapwood
G.2.12 Column 12 — Termite-resistance of heartwood
G.2.13 Column 13 — Early fire hazard indices
G.2.14 Column 14 — Colour
Appendix H
Appendix I
Appendix J
J.1 General
J.2 Vertical nail lamination
J.3 Floor framing
J.3.1 Cuts, holes and notches in bearers and joists
J.3.2 Bearers
J.3.3 Joists
J.3.3.1 Solid section
J.3.3.2 I-joists
J.3.4 Notching and cutting over bearing points
J.3.5 Bearing points for concentrated loads
J.3.6 Deep joists — Lateral restraint
J.3.6.1 Blocking and rim boards
J.3.6.2 Nailplate connectors
J.3.6.3 Intermediate blockings
J.4 Roof framing
J.4.1 Roof bracing
J.4.2 Rafters
J.4.3 Ceiling joists
J.5 Bracing details and shear forces for internal walls
J.6 Fixings and tie-down design