Do you have a flat pitched roof, clay or concrete tile roof?
To replace and change to colour steel long run requires a builder. Because I am a Certified Builder as well, that is simple, two birds with one stone! Tiled roofs, sit on battens where they are wired down. Whereas, colour steel long run sits on purlins, timber that is larger in size and iron is screwed to. It’s not a good feeling sitting inside a house with old tired and very heavy tiles. Not only an earthquake risk, but a leak hazard that cannot be fixed easily without breaking more to get to leak. Let me replace it for you and never look back.
Flat roofs cannot be re-roofed using iron, as anything under a 3 degree angle/pitch needs to be a water proof membrane. Water proof membranes afford home owner a 10/ten year warranty. But as a certified Builder, I can “re-pitch the existing roof, install insulation at same time, and place new roof over. Nothing is too complex.