Specifications

STANDARD SPECIFICATION - BUILDINGS
DPI REFERENCE TEXT - APRIL 2009
PAGE 13
TIMBER & STEEL CONSTRUCTION
AS 1604.1 or alternatively with BFCA salts by
the CSIRO approved dip-diffusion process. The
minimum dry salt retention in permeable species is
5.6 kg/m3 to all timber with susceptible sapwood.
Timber grades
Hardwood: To AS 2796.1
Grading: To AS 2796.2
Structural Timbers: Generally F14 minimum.
Timber Trusses: To the truss manufacturers design.
Fasteners
Use fasteners capable of transmitting the loads
imposed, and sufcient to ensure the rigidity of the
assembly. Do not split or otherwise damage the
timber.
Adhesives
Use adhesives capable of transmitting the loads
imposed, and sufcient to ensure the rigidity of the
assembly and that do not cause discolouration of
nished surfaces.
Structural Adhesives: To AS/NZS 1328.1
Finished sizes
Use milled timbers with actual dimensions which
are not less than stated dimensions, except for
dimensions qualied by a term such as “nominal”
or “out of” to which industry standards for nished
sizes will apply. If unseasoned timber is used, or
variations in moisture are likely, make allowance for
shrinkage, swelling and differential movement.
Coating: Before placing bolts in contact with ACQ
treated timber, coat the shank of the bolt in a grease
or bituminous coating.
Structural plywood
Standard: To AS/NZS 2269.0
Bond: Type A.
Flooring: Tongued and grooved.
Veneer quality to visible surfaces: C (Minimum).
Structural sheet ooring
Installation: Fix 17 mm thick F14 Grade structural
plywood ooring with elastomeric adhesive to
AS 2329 in addition to nailing or screwing. Sand
junctions lightly to a smooth, level surface.
Timber decking
Denition: Timber ooring with plain, bevel or pencil
round edge suitable for pedestrian or light vehicle
loadings in balconies, decks and access ways.
Timber (Minimum requirements): Hardwood species
of durability Class 2, size 70 x 19 mm nished.
Installation: Lay in long lengths (minimum 3 spans)
Stagger joints and make them over joists. Leave 4
mm between edges of boards.
Fixing: No 10 Countersunk head tek screws
corrosion protection class 3. 2 No screws to each
joist.
Surface nish: Apply the rst coat all round before
xing.
Fibre cement ooring
Compressed sheets: To AS/NZS 2908.2, Type A,
Category 4.
Thickness: Generally 15 mm.
Proprietary item: Hardies or CSR compressed
sheet.
Installation: Lay the length of the sheets at right
angles to the joists and continuous over at least
2 spans. Stagger the end joints and locate them
centrally over joists. Butter the edges of sheets
with adhesive and rmly butt join together. Provide
expansion joints as recommended by the sheet
manufacturer.
Fixing: Fix to joists with countersunk screws.
Wall framing
Gauging: Use gauged timbers in studs, noggings
and plates for double faced walls.
Generally 100 x 50 studs at 450 max. crs.
Timber species or group: Hardwood. Minimum
stress grade F14.
Provide additional support in the form of noggings,
trimmers and studs for xing lining, cladding,
hardware, accessories, xtures and ttings as
required.
Damp-proof courses
Provide Super Alcor damp-proof courses under the
bottom plate of stud walls built off slabs or masonry
dwarf walls.
4.7 TIMBER ROOF TRUSSES
Approved manufacturer
Use timber roof trusses prefabricated by an
approved manufacturer.
Shop drawings - Hold Point
Hold Point: Submit shop drawings showing the truss
arrangement, location, loading, timber species,
grade and sizes, joint details, lifting points and
method of xing and bracing.
Marking: Permanently mark each truss to show
the manufacturer, timber species, location, support
points and other relevant data.
Certication: Provide with the shop drawings
certication of the structural sufciency of the truss
and roof design supplied on a completed NT Building
Act Section 40 Certicate of Compliance form.
Installation
Standard: To AS 4440.
Support trusses on bottom chord at two points only,
unless designed for additional support. Plumb to
within H/200, where H is the height at the apex.
Provide the required ties and wind bracing. Over
internal walls provide not less than 10 mm vertical
clearance and use bracing methods which allow for
vertical movements.
Specifications March 2009.indd 13 11/03/2009 11:47:10 AM