Posts and wall frames are defective if they deviate from vertical by more than 4 mm within any 2 m height. Refer to Figure 0.03 in this Guide for method of measurement.
4.03 Straightness of timber frame surfaces
Frames are defective if they deviate from plane (horizontal or vertical bow) by more than 4 mm in any 2 m length of wall. Refer to Figure 0.03 in this Guide for method of measurement.
Frames that will be subject to the subsequent fixing of plasterboard must be such that when a 1.8m straightedge is placed over the wall frame the maximum deviation from the straightedge must not exceed 4mm over 90% of the area and not exceed 5mm over the remaining area.
Frames that exceed these tolerances are defective. Refer Figure 4.03 which reproduces Table 4.2.2 from Australian Standard AS 2589.
VERTICALITY OF STUMPS, POSTS OR PILES
1000 mm
Ground level
Spirit level 20 mm
maximum deviation overall
10 mm maximum deviation in first 1000 mm
VERTICAL PLUMB LINE
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Figure 4.03
DEVIATION IN THE POSITION OF THE BEARING SURFACE OF THE FINISHED FRAMING
Substrate type
Levels 3 and 4 Level 5
Deviation of 90% of area (mm)
Deviation of remaining area (mm)
Deviation of 90% of area (mm)
Deviation of remaining area (mm) Steel and timber
framing and battened masonry
4 5 3 4
Deviation from plane in arrow direction shall not exceed the tolerance in Table 4.03
1.8m straight edge
Extract from AS2589 - Gypsum lining - Application and finishings5
5 Reproduced with permission from SAI Global Ltd under licence 1405 - C0128
4.04 Steel wall frames
Steel wall framing is defective if it does not comply with the Building Code of Australia and one of the following AS4100 – Steel structures, AS/NZS 4600 – Cold formed steel structures, or NASH – Residential and low-rise steel framing – Part 1 Design criteria.
Walls are defective if they are not positioned within 5mm of their specified position.
Walls that are specified as straight are defective if they deviate by more than 5mm over a 3 metre wall length and where wall panels join to form a continuous wall, the critical face or faces of the panel are defective if they deviate by more than 2mm at the joint.
Frames that will be subject to the subsequent fixing of linings must be such that when a 1.8m straightedge is placed over the wall frame the maximum deviation from the straightedge must not exceed 3mm over 90% of the area and not exceed 4mm over the remaining area.
Frames that exceed these tolerances are defective.
Walls must not deviate from vertical by more than H/600 where H is the height of the wall, or 3mm, whichever is the greater.
Loadbearing structural walls are
defective if the gaps between the bottom plate and concrete slab are greater than 3mm and are not packed at each stud with load bearing shims or grout. Non-loadbearing walls are defective if gaps between the bottom plate and concrete slab exceed 3mm and the gaps are not filled at each jamb stud and at points where fixed to the slab with load bearing shims or grout.
4.05 Packing under timber bearers
Packing to stumps or piers under bearers is defective if it is not made of durable, non-compressible materials, such as engineered plastic packers, or does not provide the minimum bearing area required by the AS 1684 – Residential timber-framed construction, or is more than a total thickness of 20 mm or is not fixed in a workman- like manner.
4.06 Attachment of joist, bearers and trusses to steel wall frames
Attachment of floor joists, bearers, trusses and rafters to walls is defective if the gap between these members and the wall exceeds 3mm and the gap is not packed with load bearing shims.
Trusses, rafters and ceiling joists are defective if they are not positioned within 5mm of their specified position.
4.07 Timber shrinkage
Timber is defective if it has shrunk more than 10% if it is unseasoned or 3% if it is seasoned.
4.08 Fixing timber stud walls to concrete slabs
Fixing of timber bottom plates is defective if it does not comply with the Building Code of Australia, Australian Standard AS 1684 – Residential timber-framed construction and the fixing manufacturer’s installation requirements.
Depending on the manufacturer’s requirements for the concrete nail/
35
masonry anchor used and the required uplift pull-out force and wind category, the distance of the fixing from the edge of the slab is required to be between 50 to 70 mm minimum for standard 20 MPa concrete.
The fixing point cannot be less than five times the diameter of the fastener from the edge of the timber plate which equates to 25 mm for a 5 mm diameter nail and 50 mm for a 10 mm diameter masonry anchor.
4.09 Fixing metal stud walls to concrete slabs
Fixing of metal bottom plates is defective if it does not comply with the Building Code of Australia and the fixing manufacturer’s installation requirements.
4.10 Treads and risers in stairs in non-fire rated stairs
Timber stairs are defective if they do not comply with the requirements of the Building Code of Australia. The top and bottom risers may be varied to allow for the installation of the approved documented floor finishes, to provide uniform and constant riser height throughout after the installation of the approved floor finishes. This also applies to top and bottom risers of concrete stairs.
A tolerance of up to 5 mm from the nominated dimensions in the approved documents is considered acceptable to allow for the variation in behaviour of timber used in the construction of the stair caused by atmospheric moisture changes.
This tolerance shall not be applied to allow for poor construction practice.
Refer to figure 4.10
Figure 4.10
Top tread or landing
Landing or floor level 5mm variation in
Tread/going 15mm variation in
First riser height 5mm variation in
riser height
15mm below landing or 5mm above variation in last riser height
4.11 Bottom plates that overhang concrete slabs
Bottom plates that are at least 90 mm wide and overhang concrete slabs by in excess of 15 mm are defective and bottom plates that are 70 mm wide and overhang slabs by in excess of 10 mm are defective. In each instance, these permissible overhangs, are subject to the minimum edge distance for both the bottom plate and the concrete slab fixing locations being satisfied and minimum cavity widths as required by the Building Code of Australia also being maintained.
Refer Figure 4.11
4.12 Timber durability
Timber used for structural purposes is defective if it does not have adequate durability for its relevant exposure conditions as defined in the Building Code of Australia and Queensland Government, Department of Agriculture, Fisheries and Forestry - Construction Timbers in Queensland.
Documented width of cavity Fastener’s minimum edge distance from edge of the bottom plate
Fastener’s minimum edge
distance from concrete edge requirements
15 mm maximum brick overhang as per BCA 10 mm
maximum for 70mm studs 15mm maximum for 90mm studs
Masonry wall skin Stud