AS 1684 RESIDENTIAL TIMBER FRAMING CONSTRUCTION (AS 1684.2)

1.1 Scope

AS 1684 specifies requirements for building practice and the selection, placement and fixing of the various structural elements used in the construction of timber-framed Buildings as defined by the Building Code of Australia and within the limitations given in Clause 1.6.

The deemed to satisfy provision describe the requirements. These provisions allow timber framing in :
  • all Class 1 buildings
  • Class 2 buildings to 3 storeys (4 storeys where ground storey is concrete/masonry carparking)
  • Class 3 buildings to 2 storeys

    USE OF ALTERNATIVE MATERIALS OR METHODS

    This Standard does not preclude the use of framing or fastening methods or materials other than those specified. Alternatives may be used, provided they satisfy the requirements of the Building Code of Australia.

    Figure 1  Conventional Frame
    Figure 2  Post and Beam Structure

    Wind Classification

    Either AS 4055 – Wind Loads for Housing (the simplified wind classification standard) or AS 1170.2 SAA Loading code Part 2 – Wind loads shall be used to determine the wind classification necessary for the use of this Standard.
    Where the wind classification is determined from AS 4055, the maximum building height limitation of 8.5m given in AS 4055 shall apply to this Standard.
    (The height limitation of 8.5 m to the ridge applies when using AS 4055 because this height is used by AS 4055 to determine the appropriate wind classification.)

    Wind classification  (non-cyclonic)

    Wall height

    The maximum wall height shall be 3000 mm (floor to ceiling) as measured at common external walls, i.e. not gable or skillion ends.
    The maximum roof pitch shall be 35° (70:100).
    Roof construction shall be hip, gable, skillion, cathedral, trussed or pitched or in any combination of these.

    Building Masses

    DESIGN CRITERIA

    The basis of the design used in the preparation of this Standard is AS 1684.1 and AS 1720.1.

    The design dead, live, and wind loading recommended in AS 1170.1, AS 1170.2 and AS 4055, were taken into account in the member computations, with appropriate allowances for the distribution of concentrated or localized loads over a number of members where relevant.

    FORCES ON BUILDINGS

    The design of framing members may be influenced by the wind forces that act on the specific members. When using Span Tables in the Supplements, the appropriate wind classification (e.g. N2) together with the stress grade shall be established prior to selecting the appropriate supplement to obtain timber member sizes.

    The main forces acting on buildings are:

                     Dead Loads      the forces arising from the weight of the building components themselves.

                     Live Loads       the forces arising from the weight of persons using the building and moveable furniture.

                     Wind Loads      the forces arising from - gales, thunderstorms & tropical cyclones.

    GUIDELINES FOR DESIGN USING THIS STANDARD

    Bracing and tie-down requirements should also be considered when determining the basic frame layout to ensure any necessary or additional framing members are correctly positioned.

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