Roofing reference
Minimum Roof Pitch by Material
The lowest pitch each roofing system is allowed on, from the US International Residential Code, Australian standards and UK guidance, with both X/12 and degrees for every limit.
Minimum pitch chart
| Material | System | Minimum pitch |
|---|---|---|
| Asphalt shingles | Asphalt shingles, standard application | 4/12 (18.4°) |
| Asphalt shingles | Asphalt shingles, low-slope application | 2/12 (9.5°) |
| Metal roofing | Standing-seam metal panels | ¼/12 (1.2°) |
| Metal roofing | Lapped (exposed-fastener) panels with applied lap sealant | ½/12 (2.4°) |
| Metal roofing | Lapped (exposed-fastener) panels without sealant | 3/12 (14.0°) |
| Metal roofing | Metal roof shingles | 3/12 (14.0°) |
| Metal roofing | Lysaght Klip-Lok 700 Hi-Strength (concealed fix, AU) | 1° (0.21/12) |
| Metal roofing | Lysaght Trimdek (trapezoidal, AU) | 2° (0.42/12) |
| Metal roofing | Lysaght Custom Orb (corrugated, AU) | 5° (1.05/12) |
| Colorbond steel | Custom Orb (corrugated, 762 mm cover) | 5° (1.05/12) |
| Colorbond steel | Trimdek (trapezoidal, 762 mm cover) | 2° (0.42/12) |
| Colorbond steel | Klip-Lok 700 Hi-Strength 0.48 BMT (700 mm cover) | 1° (0.21/12) |
| Colorbond steel | Klip-Lok 700 Hi-Strength 0.42 BMT (700 mm cover) | 2° (0.42/12) |
| Roof tiles | Clay & concrete tile (US), with double underlayment below 4/12 | 2½/12 (11.8°) |
| Roof tiles | Concrete & terracotta tiles (Australia) | 15° (3.22/12) |
| Roof tiles | Plain tiles, clay or concrete (UK, double lap) | 35° (8.40/12) |
| Roof tiles | Interlocking single-lap tiles (UK) | Product specific |
| Slate | Slate & slate-type shingles (US) | 4/12 (18.4°) |
| Slate | Natural slate, double lap (UK) | 20° (4.37/12) |
| Wood shakes & shingles | Wood shingles (IRC) | 3/12 (14.0°) |
| Wood shakes & shingles | Wood shakes (IRC) | 3/12 (14.0°) |
| Wood shakes & shingles | Wood shakes (IBC, commercial) | 4/12 (18.4°) |
| Flat roofs (EPDM, TPO, felt) | Built-up roofing (US) | ¼/12 (1.2°) |
| Flat roofs (EPDM, TPO, felt) | Modified bitumen (US) | ¼/12 (1.2°) |
| Flat roofs (EPDM, TPO, felt) | EPDM / thermoset single-ply (US) | ¼/12 (1.2°) |
| Flat roofs (EPDM, TPO, felt) | TPO / PVC thermoplastic single-ply (US) | ¼/12 (1.2°) |
| Flat roofs (EPDM, TPO, felt) | Mineral-surfaced roll roofing (US) | 1/12 (4.8°) |
| Flat roofs (EPDM, TPO, felt) | Any flat roof covering (UK, finished fall) | 1:80 fall (0.7°) |
Manufacturer instructions and local codes can be stricter. Open a material for the conditions behind each limit.