Study Notes — CPCCCA3017 Install exterior cladding

CPCCCA3017 CPC Training Package Study notes

Install exterior cladding

This unit covers fixing exterior cladding — horizontal weatherboards and sheet panelling — to wall frames, from planning and frame preparation through weatherproofing, set-out and fixing, to clean-up. Getting it right keeps the building watertight, energy-efficient and compliant with the National Construction Code — and keeps water out of the frame for the life of the building.

Prerequisite: CPCCWHS2001 (your general construction induction — white card — unit). Reading time: about 8 minutes.

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1Plan and prepare

Read the job first. Work through the drawings, specifications and work instructions, then plan the sequence of work before you pick up a tool — which walls first, where the set-out starts, what has to be on the frame before the first board goes on.
Plan to comply. Your work must line up with laws and regulations, the National Construction Code (NCC) — including its fire protection provisions — Australian Standards, WHS and environmental requirements, the manufacturer's specifications, workplace requirements, and the drawings and specs for the job. When the manufacturer's instructions and the drawings disagree, raise it — don't guess.
Tools and equipment: select what the task needs, check everything is serviceable (leads tested and tagged, guards fitted, blades sharp) and report or tag out anything faulty.
PPE per task, not per day. The gear changes with the job: eye and hearing protection for cutting, a P2 respirator and dust extraction when cutting fibre cement, gloves for handling sheets, harness or edge protection when working at height.
Inspect the site and control the risks. Walk the work area, identify hazards (overhead services, uneven ground, other trades, falling objects), apply controls, and set up the required signage and barricades. Follow the SWMS where one applies.
Materials: select what the task needs, calculate quantities (allow for laps and waste), handle them safely — sheets carried on edge, team lifts for long boards — and stack and position them ready for use, off the ground and supported so they don't bow.

2Prepare exterior wall frames

Cladding telegraphs every fault in the frame behind it. The frame gets fixed first — never the cladding over the top of a problem.

Check frames are true and plumb with a level and straightedge (or string line) before anything goes on the wall.
Straighten the face: trim high studs and pack low ones so the wall face is even right across studs and noggings — a straight plane for the cladding to land on.
Fit and fix rows of noggings to line, flush with the wall face, so every fixing point and every sheet edge has solid backing.
Prepare the frame to the cladding manufacturer's installation instructions — required stud spacings, extra trimmers at openings and joints, cavity battens if the system calls for a drained cavity.

Rule of thumb: a straight frame plus a straight first row gives a straight wall. Fix the frame, not the symptom.

3Fix thermal and moisture management

Cut, fit and secure the weatherproofing layer — sarking / pliable membrane (vapour barrier) — and the flashings. Work from the bottom of the wall up so every lap sheds water outwards: upper layers always over lower layers.
Lap and tape the membrane to the manufacturer's specification; seal around penetrations. A torn or back-lapped membrane is a leak waiting for the first storm.
Flash openings properly: head, sill and jamb flashings at windows and doors direct water out over the cladding face, never behind it.
Ancillary materials — cavity battens, thermal break strips (essential on steel frames), vent and vermin strips — identify where each one goes, cut to required lengths, then position and secure exactly as the manufacturer's installation instructions describe.

4Set out, cut and fix horizontal weatherboards

Work out the effective cover — the exposed face of each board — from the recommended lap, the board's type and profile, and the height of the wall. Cover = board width − lap.
Produce a set-out rod (storey rod) or jig marked with every row height, and use it everywhere — corners, openings, both ends of every wall.
Transfer the set-out: mark the height of each row on the building paper or the corner stops so every board lands in the same place right around the building.
Cut boards to fit the full length of the wall face, or to join on an intermediate stud where the wall is longer than the board.
Butt joints land at the centre of studs, flush to face and in line — and staggered from row to row so joints don't stack above each other.
Manufactured boards (fibre cement, engineered timber, composite) are joined using the manufacturer's specified method — off-stud jointers, backing strips or sealed joints as the system requires.
Internal and external corners are fixed and finished to the manufacturer's specification — corner stops, mitres or purpose-made mouldings, with flashings behind.

Cross-section through two lapped weatherboards. Only the effective cover advances up the wall each row — the lap is hidden behind the board above.

On the tools: in assessment you'll produce a set-out rod for at least 2.1 m of wall height from a given profile's effective cover, and clad to eave height with two different profiles — including an internal and an external corner with stops, flashings and sarking for a window and a door.

5Fix panelling (sheet and vertical cladding)

Plan the starting position of the first panel against windows, doors and corners so the finished effect matches the specified design — balanced cuts at each end of the wall, no sliver-width panels beside an opening.
Cut panels to the height of the wall, allowing the required clearances at the bottom edge and under eaves.
Abutting joints between panels follow the manufacturer's specification and the flashing requirements — vertical joints need the system's jointers, cover strips or flashings so water can't track into the joint.
Fix panels plumb and level — check the first panel with a level, and keep checking as you go, because every panel copies the one before it.

6Clean up

Clean up to legislative and workplace requirements: sort waste for disposal or recycling, handle leftover materials safely, and deal with hazardous waste (fibre cement offcuts and dust, sealant cartridges) the way the workplace procedure and the SDS say — never dry-sweep silica dust.
Check, maintain and store tools and equipment — clean them, check for damage, store them properly, and report any faults so the next user doesn't inherit a problem.

★Know this cold

Rules and standards

The NCC sets the compliance requirements for external cladding — including weatherproofing, fire protection, and moisture and energy-efficiency performance. AS 1562 (Design and installation of sheet roof and wall cladding) is the key Australian Standard for this unit.
Some cladding forms part of a fire-rated system. A tested system is a complete recipe — cladding, fixings, cavity, backing and jointing together. Substituting any component can void the fire rating and the compliance of the whole wall.
Workplace quality policies and standards apply: tolerances, hold points, inspections, and doing it once to spec.

Materials, forms and systems

You need to know common cladding materials and how both sheet and linear (board/plank) styles are applied — plus manufactured strips, sheets, boards and planks:

Material	Common forms	Key points on the tools
Timber	Weatherboards (bevel, rusticated, shiplap), board-and-batten	Prime all faces and cut ends; allow for movement; nail to spec.
Fibre cement	Planks, sheets, panels	Silica dust hazard — score-and-snap or dust-extracted cutting, P2 respirator; joint per manufacturer.
Metal	Profiled sheet, interlocking panels	Compatible fixings to avoid corrosion; allow for thermal movement; AS 1562 applies directly.
Vinyl / PVC	Interlocking planks	Fix loose in slotted holes — it must be free to expand and contract.
Engineered / composite	Planks and panels	Follow the system exactly — laps, gaps, fixings and jointers are all specified.

Pliable membranes, thermal break strips, sheets and battens: the membrane is the second line of defence against water; thermal breaks stop heat bridging (mandatory consideration on steel frames); cavity battens create a drained, ventilated gap behind the cladding.
Flashing and sarking process: bottom-up installation, laps shed outwards, flashings integrated with the membrane at every opening and penetration.

Safety and handling

The big hazards on cladding work: working at heights, silica dust from fibre cement, manual handling of long and heavy boards and sheets, power tool use, and other trades below.
Safe handling and storage: sheets on edge, boards stacked flat and supported, hazardous waste and dust disposed of per workplace procedure and the SDS.

Reading the job and calculating quantities

Be able to pull cladding type, coverage, fixing details and corner/opening treatments from plans, specifications and elevation drawings.
Know your tools and equipment: levels, string lines, set-out rods, drop saws and shears, fibre-cement guillotines and score-and-snap knives, nail guns, dust-extracted saws.
Calculating rows: wall height ÷ effective cover, rounded up — then tighten the cover so rows land evenly. Example: 2 700 mm ÷ 170 mm = 15.9 → 16 rows at 2 700 ÷ 16 ≈ 169 mm cover.
Frame construction matters: timber frames take nails direct; steel frames need screws or specified fasteners plus thermal break strips; stud spacing and nogging rows set your fixing pattern and where joints may land.

!Where people slip up

The slip

Cladding straight over an unchecked frame — “the boards will pull it straight.”

The fix

They won't. Check true and plumb first, then trim and pack until the face is even. Cladding telegraphs every bump and hollow in the frame.

The slip

Sarking lapped the wrong way, or flashings that tip water back towards the frame.

The fix

Think like a raindrop: every lap and every flashing must direct water down and out. Upper layers over lower layers, always — head flashings discharge over the cladding face.

The slip

Measuring each row up the wall board by board instead of using a set-out rod.

The fix

Small errors accumulate and the rows wander. Mark every row height on one rod, then transfer it to every corner and opening — rows stay parallel and line up right around the building.

The slip

Treating fibre cement dust as ordinary sawdust.

The fix

It contains crystalline silica. Score-and-snap or use dust-extracted cutting, wear a P2 respirator, keep others clear, and never dry-sweep the offcut dust.

The slip

Swapping fixings or components inside a manufacturer's system or a fire-rated wall because “they're basically the same.”

The fix

The tested system is the whole recipe. Substituting any part can void the fire rating, the warranty and NCC compliance. Use exactly what the specification calls for, or get a documented change.

AMini-glossary

Sarking / pliable membrane: The flexible weatherproofing and vapour-barrier layer fixed over the frame behind the cladding — the wall's second line of defence against water.
Effective cover: The exposed face of each board once lapped — board width minus lap. What actually advances up the wall each row.
Lap: The overlap between one board and the board above it, which keeps the joint weathertight.
Set-out rod (storey rod): A straight length of timber marked with every row height, used to transfer the set-out identically to every corner and opening.
Nogging: A short horizontal member fixed between studs — stiffens the frame and gives fixing/backing for cladding edges.
Flashing: A shaped strip (metal or purpose-made) that directs water out and over the cladding at openings, joints and penetrations.
Stop (corner stop): A vertical trim at an internal or external corner that weatherboards butt into, closing and weathering the corner.
Plumb and true: Plumb: exactly vertical. True: straight and in plane, with no twist, bow or hollow.
Cavity batten: A batten fixed over the membrane that holds the cladding off the frame, creating a drained, ventilated gap.
Thermal break strip: An insulating strip between cladding or battens and a steel frame, stopping heat bridging through the metal.
Butt joint: An end-to-end joint between boards in the same row — landed at the centre of a stud, flush and in line, and staggered row to row.
Telegraphing: When faults in the frame show through the finished cladding as visible bumps, hollows or wavy lines.

That's the lot

You've covered every element of CPCCCA3017 — planning, frames, moisture management, weatherboards, panelling and clean-up. Mark the notes finished when you're done.

✓ Notes marked as finished — good work.