What is the minimum roof pitch in Australia?

It depends on the roofing. For metal sheet, the NCC sets it in Figure 7.2.3: corrugated 5 degrees, trapezoidal 2 degrees, concealed-fastened 1 degree. For tiles, your tile maker sets the minimum, not the code. Sheet makers can also ask for more than the code, so check the product sheet.

Does the NCC or the manufacturer set the pitch for metal roofing?

Both matter. The NCC sets a code minimum for each profile in Figure 7.2.3. Corrugated is 5 degrees, for example. Your sheet maker often asks for more for their product. Follow whichever number is steeper. Lay flatter than that and the roof fails the code.

What sets the minimum pitch for a tiled roof?

Your tile maker does. The NCC has no minimum pitch for tiles. Check AS 2050 and your tile maker's fixing sheet. AS 2050 covers roofs at 15 degrees or steeper. Flatter than that, ask the tile maker. Never take a tile minimum from a mate's job.

Do tiled roofs need sarking?

Yes, when the pitch is under 18 degrees. Sarking is the foil-backed blanket under the tiles. It catches wind-blown rain and dust. Take care: 18 degrees is a sarking trigger, not a minimum pitch. It says when sarking goes in, not how flat you can lay tiles.

How do I check my roof pitch on site?

Measure the rise, measure the run, then turn them into degrees. A 1 m rise over a 4 m run is about 14 degrees. The roof-pitch calculator does the maths. Then check that number against your profile's minimum in NCC Figure 7.2.3.

In this section

Minimum Roof Pitch (NCC 2025): Metal vs Tile

What sets your roof's minimum pitch under the NCC — the code fixes it for metal sheet, your tile maker sets it for tiles — and how to check your pitch fast.

NCC 2025 Clause HP 7.2/7.3

The requirement

For metal sheet roofing, the NCC sets the minimum pitch: corrugated 5°, trapezoidal 2°, concealed-fastened 1° (NCC 2025, Figure 7.2.3). For roof tiles, the code sets no minimum. Your tile maker sets it, with AS 2050.

Roof pitch is how steep your roof is. Lay it too flat and water sits on the roof instead of running off. So there is a limit on how flat you can go. Who sets that limit depends on what you are laying (NCC 2025, Housing Provisions Parts 7.2 and 7.3).

What you’re laying	Who sets the minimum pitch
Metal sheet roofing	The NCC — your profile’s minimum is in Figure 7.2.3
Roof tiles	Your tile maker — check AS 2050 / the manufacturer

Metal sheet: the code sets it. The NCC gives each profile its own minimum pitch. The numbers sit in Figure 7.2.3 (clause 7.2.3). The code does not pass this job to AS 1562.

Metal sheet profile	NCC minimum pitch
Corrugated	5°
Trapezoidal (incl. close-pitched)	2°
Concealed-fastened (secret-fix)	1°

One catch. Your sheet maker can ask for a steeper pitch than the code. Check the product sheet. If the two numbers differ, follow the steeper one. The calculator turns your rise and run into degrees. Then you can hold that number against your profile’s minimum.

Roof tiles: the tile maker sets it. The NCC has no minimum pitch for tiles. That number comes from your tile maker and AS 2050, the tiling standard. AS 2050 covers roofs at 15 degrees or steeper. Flatter than that, ask the tile maker. Never take a tile minimum from another job. Check the fixing sheet for the tile you are laying.

NCC 2025 Housing Provisions 7.2

One more tile rule: sarking. A tiled roof flatter than 18 degrees needs sarking. Sarking is the foil-backed blanket under the tiles. It catches wind-blown rain and dust. Take care with this one. 18 degrees is a sarking trigger, not a minimum pitch. It says when sarking goes in, not how flat you can lay the tiles.

Worked example

You have framed a roof. The rafters climb 1 m over a 4 m run. What is the pitch, and is it steep enough?

Get the rise and the run. The rise is how far the roof climbs: 1 m. The run is how far it travels flat to get there: 4 m.
Turn it into degrees. A 1 m rise over a 4 m run is about 14 degrees. The calculator does this bit for you.
Check it against the minimum. Running corrugated? Its minimum is 5 degrees, so 14 is well clear. Even concealed-fastened at 1 degree passes. If your pitch had come in under the minimum, you would be too flat. You would need to lift the pitch or change profile. And check your sheet maker’s spec, since it can ask for more than the code.

Laying tiles instead? Work out the same 14 degrees. But check it against your tile maker’s minimum and AS 2050, not Figure 7.2.3. And under 18 degrees, the tiles need sarking.

Do it in 5 seconds

Part of the NCC rule book for Australian chippies — the pillar, with the plain-English tour of what actually applies to your work.
Getting water off the roof once it runs down: gutters & downpipes: NCC sizing basics.

Sources

NCC 2025, ABCB Housing Provisions Standard, Part 7.2 “Sheet roofing” (clause 7.2.3, Figure 7.2.3) — sets the minimum pitch for each metal sheet profile: corrugated 5°, trapezoidal 2°, concealed-fastened 1° (confirmed against NCC 2025 Figure 7.2.3, and unchanged from NCC 2022). Manufacturers may specify higher. See ncc.abcb.gov.au.
NCC 2025, ABCB Housing Provisions Standard, Part 7.3 “Roof tiles and shingles” — the under-18-degree sarking trigger for tiled roofs. Confirm at ncc.abcb.gov.au.
AS 2050 (Installation of roof tiles) and your tile manufacturer — set the minimum installable tile pitch; the NCC does not. AS 2050 applies to roofs at 15 degrees or more; below that, check with the tile manufacturer. The tile pitch figure must be confirmed there, not from the NCC.

More Australia rules

Roofing in other countries

Frequently asked questions

What is the minimum roof pitch in Australia?: It depends on the roofing. For metal sheet, the NCC sets it in Figure 7.2.3: corrugated 5 degrees, trapezoidal 2 degrees, concealed-fastened 1 degree. For tiles, your tile maker sets the minimum, not the code. Sheet makers can also ask for more than the code, so check the product sheet.
Does the NCC or the manufacturer set the pitch for metal roofing?: Both matter. The NCC sets a code minimum for each profile in Figure 7.2.3. Corrugated is 5 degrees, for example. Your sheet maker often asks for more for their product. Follow whichever number is steeper. Lay flatter than that and the roof fails the code.
What sets the minimum pitch for a tiled roof?: Your tile maker does. The NCC has no minimum pitch for tiles. Check AS 2050 and your tile maker's fixing sheet. AS 2050 covers roofs at 15 degrees or steeper. Flatter than that, ask the tile maker. Never take a tile minimum from a mate's job.
Do tiled roofs need sarking?: Yes, when the pitch is under 18 degrees. Sarking is the foil-backed blanket under the tiles. It catches wind-blown rain and dust. Take care: 18 degrees is a sarking trigger, not a minimum pitch. It says when sarking goes in, not how flat you can lay tiles.
How do I check my roof pitch on site?: Measure the rise, measure the run, then turn them into degrees. A 1 m rise over a 4 m run is about 14 degrees. The roof-pitch calculator does the maths. Then check that number against your profile's minimum in NCC Figure 7.2.3.