The BMT rating of the sheet is important as it dictates the spans that can be used for support. The higher the BMT, the larger the span between the roofs supports. The higher BMT is stronger and less easily dented or fractured, especially when people are accessing the roof to clean gutters and perform maintenance, eg. flue cleaning, aerials etc.
The 2 most commonly used BMT’s for domestic roofing are the 0.42bmt and the 0.48bmt sheets. The 0.42bmt sheets are the base range thickness and the 0.48bmt sheets are a step up from this. AusStyle Roofing recommends the use of 0.48bmt Colorbond sheets as they have superior strength compared to the 0.42bmt and are only a fraction more expensive than the 0.42bmt sheets.
The 0.48bmt sheets are better value for your money when compared against the 0.42bmt, especially if your roof is accessed frequently or subject to tree branches/debris falling onto it and it will have a longer life span.
No matter what BMT you choose, make sure it is the appropriate product for the batten spacing’s, if the wrong product is used it will jeopardise your roof sheets warranty!