# NZ Minimum Roof Pitch (E2/AS1): Tiles vs Metal The E2/AS1 minimum roof pitch for profiled metal, metal tile, concrete and clay tile, including the roof-length limits and adjustments. - Canonical HTML: https://www.chippy.tools/building-codes/nz/roofing/minimum-roof-pitch/ - Publisher: Chippy Tools - Updated: 2026-09-06 - Market: nz - Code edition / reference: NZBC E2/AS1 (4th edition, 28 July 2025) - References: NZ E2 ## The requirement New Zealand has no single minimum roof pitch. E2/AS1 sets a minimum for each kind of roofing. It runs from **3°** for trough profiled metal up to **25°** for some concrete and clay tiles. Check the length notes for the chosen roof system. Roof pitch is how steep your roof is. Lay it too flat for the roofing and water sits. Or it blows back under the laps instead of running off. The rule sits in clause E2 External Moisture of the national Building Code. The numbers used on site come from its Acceptable Solution, E2/AS1. Each kind of roofing sheds water in its own way. So E2/AS1 gives each one its own minimum pitch: | Roofing material | Minimum pitch (E2/AS1) | |-----------------------------------------|-----------------------------------------| | Profiled metal — trough | **≥ 3°** | | Profiled metal — trapezoidal | **≥ 3–4°** (crest-height dependent) | | Profiled metal — corrugated | **≥ 8°** | | Metal tile — standard profile | **12°** | | Metal tile — shingle/shake-look profile | **15°** | | Concrete tile Type I | **15°** with underlay · **20°** without | | Concrete tile Type II | **20°** | | Concrete tile Type III | **25°** | | Clay tile | **20–25°** (profile/underlay dependent) | Read the length conditions with the pitch. The profiled-metal figures cover roofs up to 18 m long **without end laps**. For longer roofs, the source directs readers to the maker. For masonry tiles, Table 8.2.3.1 adds **1° for each extra 0.5 m of rafter beyond 4.5 m**. That is an adjustment rule, not a blanket exclusion from E2/AS1. Read the metal-tile length conditions in clauses 8.3.3.2–8.3.3.3. Beyond 12 m, add 1° per extra 0.5 m. Do not apply one roof system’s length rule to another. **Diagram labels:** 4 m; 1 m; ≈ 14° NZBC E2/AS1 **A maker can go lower.** The E2/AS1 numbers are the floor for the Acceptable Solution path. They are not a hard limit on what any roof can do. A maker can have a lower pitch for their own product signed off as an Alternative Solution. That route sits outside E2/AS1. Never borrow that lower number for another product. It is tied to the maker’s own testing and detailing. ## 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? 1. **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. 2. **Turn it into degrees.** A 1 m rise over a 4 m run is about 14 degrees. The roof-pitch calculator does this bit for you. 3. **Check it against your roofing’s minimum.** Laying corrugated metal? Its minimum is 8°, so 14° is well clear. Laying a concrete Type III tile? Its minimum is 25°, so the same 14° roof is too flat. The roofing you pick changes whether the roof passes. Check length, end laps, underlay and product limits before using the table. The worked sum checks an angle, not the complete roof design. ## Related - [New Zealand Building Code hub](https://www.chippy.tools/building-codes/nz/) — how the one national Code and its Acceptable Solutions work. - [NCC minimum roof pitch (Australia)](https://www.chippy.tools/building-codes/au/roofing/minimum-roof-pitch/) — the Australian numbers, for anyone working across the ditch. ## Sources - **NZ Building Code Clause E2 External Moisture — Acceptable Solution E2/AS1 (4th edition, effective 28 July 2025)**, §8.2.3 and Table 8.2.3.1 (masonry tiles, including the longer-rafter pitch adjustment), §8.3.3.2 (metal tile roofing, rafter ≤ 12 m), and §8.4.4.1 (profiled metal roofing, length ≤ 18 m without end laps) — the source for every figure on this page. Confirmed by direct read of the current PDF at [building.govt.nz](https://www.building.govt.nz/assets/Uploads/building-code-compliance/e-moisture/e2-external-moisture/asvm/e2-external-moisture-as1-fourth-edition.pdf). E2/AS1 itself notes a manufacturer may have a lower pitch accepted outside its scope — its figures are a deemed-to-comply floor, not an absolute physical limit. **Read this first.** These are the **Acceptable Solution (E2/AS1)** figures — the deemed-to-comply path. A designer can instead use a Verification Method or an Alternative Solution, which can carry different numbers for a specific product. Always confirm the current amendment at [building.govt.nz](https://www.building.govt.nz/) before you build to it. Sourced from the New Zealand Building Code, © Crown copyright, reused under NZGOAL / Creative Commons Attribution. This page is general information for tradespeople and is not compliance, engineering or legal advice. Requirements are subject to state and territory variations and adoption timing. Always confirm requirements with your building certifier and relevant state authority. ## Frequently asked questions ### What is the minimum roof pitch in New Zealand? It depends on the roofing. Trough profiled metal can go as low as 3 degrees. Some clay and concrete tiles need 25 degrees. Check the length limits and notes for the chosen system; there is no single national minimum pitch. ### What's the minimum pitch for profiled metal roofing? For runs up to 18 m without end laps, E2/AS1 requires at least 8 degrees for corrugated metal and 3 degrees for trough profile. Trapezoidal profile needs 3 to 4 degrees, based on crest height. For longer runs, follow the manufacturer’s recommendations. ### What's the minimum pitch for metal tile roofing? Up to 12 m rafter length, standard metal tile profiles need at least 12 degrees; shingle or shake profiles need 15 degrees. Beyond 12 m, add 1 degree per extra 0.5 m. Follow stricter manufacturer requirements. ### What's the minimum pitch for concrete and clay roof tiles? Table 8.2.3.1 gives concrete and clay tile base pitches of 15 to 25 degrees, depending on profile and underlay. For rafters longer than 4.5 m, add 1 degree per extra 0.5 m. Check all table notes and the product requirements. ### Can a lower pitch be used than E2/AS1 says? A lower pitch needs evidence for the proposed compliance path. Manufacturer advice alone is not consent approval. Ask the designer for the Alternative Solution evidence and check it with the building consent authority.