COLORBOND® Corrugated Iron Roofing Sheets .42 BMT

COLORBOND® corrugated iron for steel roofing and wall cladding

Made from genuine BlueScope COLORBOND® pre-painted steel, these .42 BMT corrugated iron sheets suit residential roofing and wall cladding for homes, sheds, garages, patios and carports. The classic corrugated profile provides 762mm effective cover, and every sheet is cut to the custom length you enter when ordering.

Choose your roof colour and required sheet length above. If your project has specific span, wind or load requirements, confirm that .42 BMT is suitable before ordering.

Why choose the classic COLORBOND® corrugated profile?

✔ Classic corrugated roofing profile trusted across Australia

• ✔ Made from genuine BlueScope COLORBOND® steel
• ✔ Custom cut to your required lengths
• ✔ Strong, lightweight and easy to handle
• ✔ Suitable for re-roofing, new builds and renovations
• ✔ Wide range of genuine COLORBOND® colours available
• Is .42 BMT Right for Your Project?

.42 BMT is the most common thickness selected for standard residential roofing where normal spanning conditions apply. It offers an excellent balance of strength, weight and value.

Many customers choose .42 BMT for:

• ✔ Homes and extensions
• ✔ Sheds and garages
• ✔ Patios and verandahs
• ✔ Carports
• ✔ General replacement roofing

If your build requires heavier specifications, higher wind ratings or engineering requirements, .48 BMT or a concealed-fix profile like COLORBOND® KLIP-LOK® 700 Hi-Strength roofing may be worth considering.

.42 BMT vs .48 BMT corrugated iron: which should you choose?

Choose the sheet thickness specified for your building rather than assuming one gauge suits every project. The correct choice depends on factors including wind pressure, roof or wall spans, support spacing, building height and the fixing design.

.42 BMT may suit residential projects where the design conditions allow it. .48 BMT permits larger maximum support spacings in several applications, but it isn’t automatically suitable for every commercial building or cyclonic area. Follow the engineering or approved building plans and confirm the required specification before ordering.

If your build engineer or roofing plan doesn't specify, .42 BMT is the standard choice.

Cyclonic Areas & Wind Ratings

A thicker sheet alone doesn’t make a corrugated roof suitable for a cyclonic area. For Region C or D, the sheet thickness, support spacing, fastener type and fixing pattern must form part of a project-specific cyclonic design. Follow the approved building plans or engineer’s specification and confirm the complete roofing system before ordering. If no specification has been provided, don’t assume either .42 BMT or .48 BMT is suitable.

Sheet Coverage & Custom Lengths

Each corrugated sheet provides 762mm effective cover. This is the usable installed width after sheet overlap and matters when calculating how many sheets you need.

We cut sheets to the lengths you enter when ordering online - reducing waste, minimising joins and speeding up installation.

Full Specifications

Which COLORBOND® roof colour should I choose?

Choose from the complete range of genuine COLORBOND® roof colours, including Classic Cream™, Woodland Grey®, Monument®, Surfmist®, Shale Grey™ and Basalt®. Classic Cream™ suits traditional homes and palettes used in rural areas, while darker colours such as Woodland Grey® and Monument® can create stronger contrast on modern homes.

Darker colours generally absorb more solar heat than lighter colours. When choosing your roof colour, consider appearance alongside the roof direction, local climate, insulation and ventilation. Check your preferred colour against a physical sample before ordering because colours can appear different on a screen.

Low Maintenance COLORBOND® steel for Australian Conditions

COLORBOND® steel is tested in Australian conditions for corrosion, durability and compatibility with common building products. Correct product selection and installation still matter, particularly in coastal or high-exposure locations.

Roof surfaces naturally washed by rain generally require little maintenance. Wash unwashed areas, such as wall cladding beneath eaves, with clean fresh water at least every six months and more frequently in coastal or industrial environments.

Fast Delivery Available

We deliver COLORBOND® roofing sheets across VIC, NSW, QLD, ACT and TAS. Every order is cut after purchase to your selected lengths - made-to-order roofing without waiting on slow manual quotes.

Complete Your Roof with Matching Accessories

• ✔ Roofing screws - 12 x 50mm Multifix, colour-matched
• ✔ Flashings
• ✔ Barge cappings and ridge cappings
• ✔ Quad guttering and fascia
• ✔ Downpipes
• ✔ Insulation and sarking

Frequently Asked Questions