Roofer on a residential job: scope, licensing, tolerances, working with other trades

TL;DR

The roofer waterproofs the building envelope: tile or metal roofing, sarking, battens, flashing, ridge capping, gutters, and downpipes. AS 2050:2018 covers tile installation; AS 1562.1:2018 covers metal sheet cladding. Roofing is split into two distinct licence classes in most states: a roof tiler handles concrete and terracotta tiles, while a roof plumber handles metal cladding, gutters, flashings, and downpipes. The biggest programme risk on a residential roof package is the frame inspection hold: the frame must pass engineering sign-off before any roofing work commences, and a late inspection or a non-compliant frame stalls the roofer and everything downstream. All roofing work is HRCW (high risk construction work) under the WHS Regulations due to the fall risk exceeding 2 metres, and a SWMS is mandatory before work starts.

What this trade covers

Roofing on a residential job divides into two main streams, often performed by separate specialist trades.

Roof tiling: laying concrete or terracotta tiles over sarked and battened rafters or trusses, including tile bedding, pointing, ridge capping, hip and valley tiles, mortar, and tile ventilators. The roof tiler works to AS 2050:2018.

Metal roofing (sheet and cladding): installing corrugated steel, Colorbond, Zincalume, or other metal sheeting as the primary roof covering. The metal roofer also handles flashings, cappings, and the associated rainwater goods (gutters, downpipes). AS 1562.1:2018 governs design and installation.

Roof plumbing (often combined with metal roofing): the fixing of guttering, downpipes, roof flashings, and coverings is classified as roof plumbing in NSW and overlaps with general metal roofing work in Queensland. In NSW, this work requires a specific roof plumbing licence.

On a standard residential job, a principal builder typically engages a roof tiler, a metal roofer, or both depending on the roof type. Where the builder contracts a specialist roofing company, they often cover both streams as a combined scope.

What’s in scope (typical residential)

Tile installation to AS 2050:2018: tile bedding, pointing, batten and sarking substrate preparation, ridge and hip capping, valley tiles, eave tiles
Metal sheet roofing to AS 1562.1:2018: Colorbond or Zincalume sheet fixed to purlins or battens at the correct lap and fixing centres for the wind classification
Flashing at all roof penetrations: chimneys, skylights, plumbing penetrations, abutments with walls and parapet, valley gutters
Guttering and downpipes (roof plumbing scope): installation of eave gutters, box gutters, downpipes, and overflow provisions
Sarking installation under tiles or metal: reflective foil laminates and sarking membranes per NCC Volume Two requirements
Batten layout and fixing at the correct gauge for the tile or sheet type
Roof ventilators, skylights, and associated flashings
Roof maintenance on existing structures

What’s out of scope (often confused)

Structural framing and trusses: the chippy frames the roof structure. The roofer covers it. The roofer should not be asked to add truss members, adjust rafter cuts, or carry out structural repairs to the frame. If the frame is wrong, it goes back to the chippy before the roofer arrives.
Waterproofing membranes on flat or low-pitch roofs: membranes applied to concrete or compressed cement decks are a waterproofing trade, not the roofer. The roofer handles metal and tile; the waterproofer handles membranes. Confirm the split in the scope of works.
Internal plumbing to downpipes: the roofer installs the downpipe from gutter to ground or subfloor. Connection to the stormwater drainage system below ground (pits, pipes, kerb connections) is typically plumber scope. Confirm the handover point in the quote.
Electrical work: skylight installations with electric openers or solar panels are separate trades. The roofer flashes the penetration; the sparky wires the fitting.
Render or paint on roof tiles: specialist coatings on existing tiles are a separate trade.
Structural design for complex or non-standard roofs: anything outside AS 1684 or engineer’s truss design requires a structural engineer. The roofer installs to the design, not beyond it.

Engagement basics

Licensing, state-by-state

State	Licence class	Key rule
NSW	Roof tiling contractor licence or tradesperson certificate (NSW Fair Trading)	Required for work over $5,000 in labour and materials (including GST). Qualification: CPC30820 Certificate III in Roof Tiling. Roof plumbing is a separate licence class: CPC32620 Certificate III in Roof Plumbing or equivalent. Penalties: $22,000 individual / $110,000 company under the Home Building Act 1989 (NSW) (verified 2026-05-10).
VIC	Building and Plumbing Commission (formerly VBA)	Roofing registration required for domestic work. Tile roofing (CPC30820) and metal/roof plumbing (CPC32620) are assessed separately. Services accessed via the VBA website while the BPC transition completes. BPC formally took over from VBA on 1 July 2025 (verified 2026-05-10).
QLD	QBCC roof tiling licence; QBCC roof and wall cladding licence	Separate licence classes. Roof tiling licence: concrete and terracotta tiles, battens, flashing, skylights. Roof and wall cladding licence: metal sheet, rainwater goods, flashings (excludes terracotta and concrete tiles). Both require managerial qualification (BSBESB402) for contractor applicants. Fit-and-proper person test applies (verified 2026-05-10).
WA, SA, TAS, NT, ACT	Each state has its own scheme	Verify current licence class, insurance requirements, and threshold with the state regulator before quoting.

Roof tiling and roof plumbing are distinct licence classes in most states. A metal roofer quoting for gutters and downpipes needs to confirm they hold the correct class (roof plumbing) for that work, or sub it out to a licensed roof plumber.

Apprenticeship pathway

Roof tilers typically complete CPC30820 Certificate III in Roof Tiling (the current code, superseding CPC30812 and earlier codes) through a TAFE or RTO, usually via a 3 to 4 year apprenticeship (verified 2026-05-10).

Roof plumbers complete CPC32620 Certificate III in Roof Plumbing (current code, superseding CPC32612, CPC32611, CPC32608), also via a 3 to 4 year apprenticeship pathway (verified 2026-05-10).

HRCW and working at heights

All roofing work is high risk construction work (HRCW) under the model WHS Regulations because work at or above a 2 metre fall risk is always HRCW. The roofer (as a PCBU or worker) must prepare a SWMS before commencing roofing, set up adequate fall protection (perimeter scaffolding, guardrails, or a catch platform), and not proceed without controls in place. Builders engaging a roof subbie should sight the SWMS before the roofer commences work (verified 2026-05-10 via Safe Work Australia).

Scaffold requirements vary by roof geometry and state WHS regulator. The engaging contract (head contract or subcontract) should specify who is responsible for erecting, inspecting, and modifying the scaffold during the roofing phase.

Industry bodies

MRCAA (Metal Roofing and Cladding Association of Australia, mrcaa.com.au): industry body for metal roofers and cladding contractors. Technical guidance on AS 1562.1 compliance and product installation (verified 2026-05-10).
ARTA (Australian Roof Tile Association, rtaa.com.au): peak body for concrete and terracotta roof tile manufacturers and installers. Technical manuals on tile installation, BAL requirements, ventilation under NCC 2022, and fixing recommendations (verified 2026-05-10).

Insurance the roofer should carry

Public Liability: typical floor $5m for sole-trader residential, $10m when working under a head contractor
Workers Compensation: required for any employees or apprentices
Tool and plant insurance: not contractually required but standard for roofers with significant plant (nail guns, tile cutters, scaffold)

Current Certificates of Currency for PL and Workers Comp should be sighted before work starts. The roofer holds them; the engaging party confirms them.

Pricing basis

Roofing is commonly priced two ways:

Per square metre of roof area: common for standard tile or metal roofing where the scope is well-defined. Rates vary with roof pitch, complexity (number of hips, valleys, penetrations), and material type. High-pitch roofs and hip roofs cost more per m2 than low-pitch gables.
Lump sum: for defined scope where the roofer has taken off quantities from the plans. Preferred where drawings are complete.

Avoid agreeing to a rate without confirming: the roof area basis (measured on the slope, not the plan projection), what penetrations and flashings are included, who supplies materials (tiles or sheet, battens, sarking, flashing), and whether scaffold is in or out of the rate.

Tolerances and acceptance

Roofing is assessed at PCI against the contract spec, AS 2050:2018 (tile installation), AS 1562.1:2018 (metal), and the HIA Guide to Materials and Workmanship plus the relevant state Guide to Standards and Tolerances.

Standards baseline

AS 2050:2018 sets out requirements for the installation of concrete and terracotta roof tiles, including minimum pitches, batten spacings, tile overlap, valley and hip construction, flashing, and mortar bedding for ridge and hip cappings (verified 2026-05-10 via Standards Australia store).

AS 1562.1:2018 governs the design and installation of metal sheet roof and wall cladding (Colorbond, Zincalume, and equivalents), including lap requirements, fixing patterns, and the relationship to wind classification under AS 1170.2 (verified 2026-05-10 via Standards Australia).

Workmanship tolerances (HIA Guide pending)

Numerical limits for tile alignment, mortar joint consistency, metal sheet straightness, and gutter falls are set by the HIA Guide and the relevant state Guide. Values are pending HIA member access.

Item	Guide coverage
Tile gauge and coursing alignment	Per current HIA Guide to Materials and Workmanship and state Guide. Pending HIA member access. [HIA-139]
Mortar joint consistency (ridge and hip capping)	Per HIA Guide and state Guide. Pending HIA member access. [HIA-140]
Metal sheet alignment and straightness	Per HIA Guide and state Guide. Pending HIA member access. [HIA-141]
Gutter fall (gradient to outlet)	Per HIA Guide and state Guide. Pending HIA member access. [HIA-142]

What can be assessed independently

Tile pitch: AS 2050:2018 specifies minimum pitches per tile type. A tiled roof below the minimum pitch for the tile specified is non-compliant and will leak over time.
Flashing laps and sealant: flashing laps at penetrations and abutments are specified in AS 2050 and AS 1562.1. Insufficient lap or missing sealant is a visual defect at PCI and a water ingress risk.
Ridge and hip mortar: cracked or missing mortar on ridge cappings is a common PCI call. Mortar must be fully bedded and pointed. Dry-bedded ridges that rattle or move are a defect.
Gutter alignment: gutters must fall consistently to the outlet. A high point that ponds water breeds corrosion, mosquitoes, and overflow. This is usually visible from ground level.
Sarking continuity: laps and sealing of sarking are inspectable before battens are laid. Once battens and tiles are on, they cannot be inspected without removal.

Common defects to look for

What inspectors and clients flag at PCI and final inspection:

Cracked or hollow ridge and hip mortar: the most common tile roofing defect. Mortar that sounds hollow when tapped has de-bonded and will admit water at the first heavy rain.
Missing or inadequate flashing: flashings at chimneys, skylights, penetrations, and abutting walls are the most common entry point for water. Inadequate upstands, missing aprons, or unsealed laps are the specific failure mode.
Loose or missing ridge capping: ridge tiles bed into mortar and are mechanically fixed in cyclonic or high-wind areas. Loose ridges are an immediate safety hazard.
Gutter ponding: a gutter that ponds even after light rain has either been installed without a fall or has a low point caused by incorrect bracket spacing. Visible from the ground.
Sarking laps folded the wrong way: sarking must lap so water runs over the lower sheet, not under it. Wrong-direction laps allow condensation to track back.
Sheet metal screws misaligned or overtightened: metal roofing screws fix through the sheet crown (not the valley) for uplift resistance. Screws in the valley collect water at the fastener. Overtightened screws compress the washer and split the rubber seal, allowing water ingress.
Insufficient tile overlap or sheet lap: below the AS 2050 or AS 1562.1 minimum, the roof is non-compliant and relies on sealant alone. This is not acceptable for a permanent installation.
Downpipe not connected to stormwater: a downpipe terminating above the finish ground level or discharging against a footing is a defect. Check the scope and confirm the connection point.

Subbie quote pack, what should be in it

A complete roofer quote pack covers:

Scope: which roof surfaces are in, which are out; tile or metal (or both); penetrations and flashings included or excluded; gutters and downpipes included or excluded; supply of materials
Material specification: tile type and colour, or metal sheet profile, gauge, and finish (Colorbond colour); batten species and grade; sarking type
Pricing basis: per m2 rate (on-slope area) or lump sum; variation rate for unscoped penetrations or flashings
Scaffold: who supplies and erects; who maintains and strikes; lift rates if applicable; confirm scaffold is in place before roofer mobilises
Programme commitment: days to complete each stage (sarking and battens, tile/sheet installation, cappings, flashings, gutters); programme dependencies (frame inspection complete, scaffold up)
HRCW obligations: SWMS provided to principal contractor before work commences; method of fall protection confirmed (scaffold, harness, or edge protection)
Licence and insurance: contractor licence number and class (tiling, roof plumbing, or both), Certificates of Currency for PL and Workers Comp
Variation mechanism: written authorisation before additional work; day rate for unscoped extras

The same list reads from different sides:

For the engaging party (builder or client direct): use this list as the quote template. Require all items before signing.
For the roofer quoting: providing all of these without being asked wins jobs and reduces disputes.
For the client reviewing a builder’s engagement: this is the bar the builder should be applying.

References

AS 1562.1:2018 Design and installation of sheet roof and wall cladding, Part 1: Metal (Standards Australia) (verified 2026-05-10)
AS 2050:2018 Installation of roof tiles (Standards Australia) (verified 2026-05-10)
NSW Government: Roof tiling work (verified 2026-05-10)
NSW Government: Roof plumbing work (verified 2026-05-10)
QBCC: Roof tiling licence (verified 2026-05-10)
QBCC: Roof and wall cladding licence (verified 2026-05-10)
VBA: Plumbing registration and licensing (verified 2026-05-10)
CPC30820 Certificate III in Roof Tiling (training.gov.au) (verified 2026-05-10)
CPC32620 Certificate III in Roof Plumbing (training.gov.au) (verified 2026-05-10)
Safe Work Australia: High risk construction work requiring a SWMS (verified 2026-05-10)
MRCAA: Metal Roofing and Cladding Association of Australia (verified 2026-05-10)
ARTA: Australian Roof Tile Association technical manuals (verified 2026-05-10)
HIA Guide to Materials and Workmanship, pending member access for numerical workmanship tolerances
NCC 2022 Volume Two for Class 1 and Class 10 buildings, ABCB (verified 2026-05-10)