CertClad | Bevelback Cavity System | Radiata Pine | Installation Manual
© ITI Timspec Ltd | BC-RP-IM-V5 | CertClad is a registered Trademark of ITI Timspec Ltd
Last Updated March 2021
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FIXING DETAILS FOR WEATHERBOARD
8.1 INSTALLATION
8.1.1 FIXING METHOD - BEVELBACK WEATHEBORDS
Ensure correct nails are selected in accordance with the nail selection chart 8.1.2. below.
Nail placement is to be 35 - 40mm up from bottom edge of weatherboard. The nail must not penetrate the
underlapping (lower) board. Nail shank must be annular grooved.
Pre-drill all nail holes using a bit that is 0.3
– 0.5mm smaller than the nail shank to prevent splitting, and
ensure a snug fit.
Nail on an upward angle to prevent water running down the nail through the cavity.
Ensure nail shank has a minimum framing penetration of 35mm for painted weatherboards.
Hand-drive all nails. Gun-driven nails should not be used as they may damage the surface of the timber or
cause splitting or crushing damage in the battens.
Flat head, pentagon head or crown head nails to finish flush onto, but not into, the face of the
weatherboard.
Jolt head nails must be punched just below the surface, spot primed and filled using a two-part high quality
non-shrinking filler, and sanded smooth, prior to painting.
Ensure weatherboards are set out to achieve correct 32mm overlap at join.
One board on any given wall elevation may need to be cut down to fit wall height. Do not extend or reduce
the 30
mm lap requirement or ‘creep’ the boards to fit.
8.1.2 NAIL SELECTION CHART
Weatherboards
Nail Size
Material
Nail Head
Nail
Shank
Minimum Framing
Penetration
Painted
90 x 4.0 mm
Stainless Steel
(304 or 316)
Silicon Bronze
Jolt head
annular
grooved
to achieve
minimum 35mm
framing penetration
Refer NZBC Clause E2AS1 Table 24
Fixing lengths need to increase when installed over a rigid wall underlay to ensure minimum penetration of
fixing into the stud.
