Craigieburn's Colorbond roofs β what the northern plains does to them
The prevailing weather in Craigieburn comes off the northern plains β hot dry northerlies in summer, cold northerlies in winter, and spring hail events that are among the most severe in metropolitan Melbourne. For the Colorbond roofing that covers most of Craigieburn's estates, the primary vulnerability is not the steel panels themselves (Colorbond is engineered for this climate) but the fixings and flashings around them. Builder-grade self-drilling screws used by volume builders can develop surface rust within 10β15 years where the drill-cut head has penetrated the Colorbond coating. Apron flashings at the wall-to-roof junction on two-storey homes can lift under sustained wind uplift. And valley flashings on complex rooflines can fail earlier than expected when installed to minimum specification. These are targeted repair jobs β not full re-roofs β but they need to be addressed before corrosion spreads.

