The roofing/walling shall be 0.60mm BMT Stramit^® Curved Corrugated cladding in continuous lengths with sinusoidal ribs 16mm high, spaced at 76.2mm centres in accordance with AS 1445, curved to a radius of _____mm. Sheeting material shall be protected steel sheet to Australian Standard AS 1397, with a minimum yield stress of 300MPa (Grade G300) and an AM100/AZ150 coating with an oven-baked paint film of selected colour, or a plain AM125/AZ150 coating. 

The sheeting shall be fixed to the purlins/girts in accordance with the manufacturer’s recommendations. Suitable fixing screws in accordance with Australian Standard AS 3566, suitable for minimum corrosivity category 3, shall be used at every support with side lap fasteners installed at mid span. Sheets shall be laid in such a manner that the approved side lap faces away from the prevailing weather. A minimum of 50mm shall be provided for projection into eave gutters. Flashing shall be supplied in compatible materials as specified; minimum cover of flashing shall be 150mm.

All sheeting shall be fixed in a workman-like manner, leaving the job clean and weathertight. All debris (nuts, screws, cuttings, filings etc.) shall be cleaned off daily.

A NATSPEC work section is available for this product. Download

To ensure you receive product to suit your application it is essential that you provide us with detailed information. Please supply template and all information wherever possible.

For curving purposes it is necessary to produce a sheet with a minimum straight section at the sheet end of 100mm. All or part of this straight section can be removed upon request (docked).

Cyclonic Data for Stramit^® Curved Corrugated and Bullnose Roof Cladding can be found in the Stramit Cyclonic Areas Guide. 

Information on the use of Stramit^® Curved Corrugated and Bullnose Roof Cladding in the Darwin area can be found in deemed-to-comply sheets numbers M/149/01 and M/239/01. These are available from Stramit or on the NT BAC website.

Stramit^® Curved Corrugated and Bullnose Roof Cladding can be fixed with either 3 or 5 fasteners per sheet at each batten/purlin to meet the required performance values.

All external fastening screws must conform to AS3566 – suitable for minimum corrosivity category 3. They are to be hexagon headed and must be used with sealing washers for both roofing and walling.

For connecting to purlins or top hats in non-cyclonic regions use:

*For attaching Stramit® Curved Corrugated sheeting to battens of thickness less than 1.5mm bmt, refer to Stramit's Top Hats & Battens Product Technical Manual.

Foot traffic limits for Stramit^® Curved Corrugated and Bullnose Roof Cladding are shown for 3 alternative foot traffic categories:

Heavy – for applications with repeated maintenance, particularly where personnel may be unfamiliar with correct procedures for walking on metal roofs

Normal – based on traditional expectations, with moderate maintenance foot traffic using designated footpaths

Controlled – spans that conform to AS 1562.1:2018 with 1.1kN load specified in AS/NZ A1170.1:2002 for R2 - Other Roofs. These require minimal careful foot traffic only on the designated footpath. Suggested for use only where occasional aesthetic imperfections from foot traffic are acceptable.


Tables are based on tests to AS 1562.1:2018 and AS4040 parts 0 and 1.

For more information on foot traffic performance of Stramit's roofing profiles refer to Stramit's Foot Traffic Guide.

Stramit^® Curved Corrugated decking is manufactured from G300 colour coated steel, aluminium-zinc-magnesium or zinc-aluminium alloy coated steel. In some locations galvanised and severe environment colour coated steel may be available by arrangement.

Colour coated steels are in accordance with AS/NZ A2728:2013 – Type 4 and, for the substrate, with AS1397:2021. Aluminium-zinc-magnesium alloy coated AM100/AM125, zinc-aluminium alloy coated AZ150 and galvanised Z450 conform to AS 1397:2021. 

Stramit has a comprehensive range of colours as standard. Ask your nearest Stramit location for colour availability.

The profiles of G300 and G550 Corrugated cladding may vary and should not be used in overlapping configurations.

The minimum roof slope for Stramit^® Curved Corrugated Roof and Wall Cladding is 5 degrees for many applications.

The spans shown below take account of 'normal' foot traffic and wind resistance including local pressure zone effects. Pressures are based on AS 4055:2021 or AS/NZS 1170.2:2021.

Where the two standards differ, the worst case has been taken for each classification. Data should only be used for buildings with dimension limits given in AS 4055:2021, 7m or less in average height, 16m max width and length less than 5 times the width, where both length and width exceed the building height and site is unaffected by land topography. Maximum roof pitch 35º. For bullnosed roofs the span is to be taken as the sheet length between fastening positions at supports.

Internal spans must have both end spans 20% shorter.

TC - Terrain category. FS, PS, NS - Full, partial and no shielding. Internal pressure coefficient +0.2/-0.3, external pressure coefficient -0.9 (roof)/ -0.65 (wall).

Values are only valid for use with steel members of 1.5mm or thicker. Where thinner supports are used, fastener capacity must be checked.

For more specific applications Stramit® Curved Corrugated cladding must be designed to the pressure and foot traffic limitations below.

Roof spans may exceed those shown in this table provided the wind pressure and foot traffic limits are not exceeded. 

Stramit® Curved Corrugated cladding can be spring curved, concave and convex, including curved ridges, provided it is sealed at the apex, and within the recommended limits shown. 

*At these radii a maximum support spacing of 900mm applies, and limit state pressure capacities are reduced by 14% for serviceability and 7% for strength. These reductions apply proportionately up to the lowest neutral radius. Minimum 5 fasteners required per sheet at ends. 

All metal roof sheeting is subject to thermal expansion and this needs to be accommodated where there is a temperature difference between the sheeting and the structure.

The colour of the sheeting will affect the amount of thermal expansion, and whether the sheet is flat or cured will affect its ability to resist without problems. Sheet lengths should be limited as follows.

Stramit^® Curved Corrugated and Bullnose Roof Cladding has limited water-carrying capacity. Roof slopes can be as low as 5° for many applications. Roof run lengths are the combined lengths of all roof elements contributing to a single pan drainage path. This can include the roof length upstream of a roof penetration that concentrates flow into other pans.

The table below gives slopes for 1% Annual Exceedance Probability (formerly 100 year ARI) rainfall intensity.

Based on AS 1562.1:2018

To avoid ponded water, minimum slope of 5º should be maintained along the entire roof length.

Stramit’s Roof Slope Guide provides additional information.

Derived from testing, the following tables give the wind load resistance for both serviceability and strength limit states.

Tables are based on testing to AS 1562.1:2018 and AS4040 parts 0 and 2. Internal spans must have both ends 20% shorter. 

Values only valid for use with steel support members of 1.5mm or thicker. Where thinner supports are used, fastener capacity must be checked. 

Refer to Stramit® Cyclonic Areas Roof and Wall Cladding Brochure for information on use in cyclonic regions. 

Stramit^® Curved Corrugated and Bullnose Roof Cladding can be installed with or without fibreglass insulation blanket. If practical, lay sheets in the opposition direction to the prevailing weather.

Installation of Stramit^® Curved Corrugated & Bullnose Roof Cladding is a straightforward procedure using the following fixing sequence.

1. Ensure all purlins are in line and correctly installed and that mesh and blanket (if specified) are in place.
2. Position and fix the first sheet ensuring the correct sheet overhangs (minimum 50mm). Ensure that screws are not overtightened to avoid indentations in walls or roofs, and fasteners have a weather-proofing seal.
3. Continue to fix subsequent sheets checking that sheet ends at the lower edge are exactly aligned.
   • It is important that the underlap of one sheet does not protrude beyond the overlap of the next – if this is unavoidable, the underlap must be trimmed locally or water ‘drawback’ may occur.
4. For sheeting that exceeds 4 metres in length straight sheets of 0.6mm Corrugated can be end-lapped with curved sheets to obtain the desired length. It is essential that sheets are laid progressively in runs across the roof, i.e. lay a continuous run of lapped sheets from eave to ridge, then start the next run. This ensures that any pitch variation is contained with one sheet width.
5. Measure the overall cover width at the top and bottom of the sheets from time to time to avoid 'fanning'.
6. For roof spans exceeding 900mm and wall spans exceeding 1200mm, stitch the sidelaps at midspan.
7. Turn up the pans at the upper roof edge and install flashings. Fix flashings according to AS 1562.1:2018.
8. Clean up the roof after each day's work, removing all screws, cuttings swarf, etc. and leave roof clean and watertight.