A tiled roof is heavy, with gravity creating a gradual but persistent downward force. It is also exposed to extreme seasonal temperatures. The combination of the two creates movement, which over time adds up to a significant shift in the position of the entire roof. This movement forces the cement used to waterproof and fix ridge cappings to crack and break away, which means water can easily leak through the broken or missing cement. The thermal and stress forces on a tiled roof can also result in individual tiles becoming cracked, which may be difficult to see from the ground, but can cause significant water leaks.
The visual appearance of a tiled roof also declines over time due to a build up of mould, lichens, dust and grime, including bacterially loaded bird droppings. This is not only unsightly, but if you intend to collect rainwater to use in your home, then the quality of your water may not be high enough for human consumption. If your tiled roof appears to be in poor condition from the ground then it probably is, and it will certainly pay to get it inspected as soon as possible.
If you want to take the opportunity to modernise your roof or change the appearance of your home, then it may be a good time to think about a Roof Conversion. This means removing the old tiles and replacing them with a ColorBond® roof.