You could repair your roof yourself however unless you are an experienced roofer I would advise against it.
Silicon can repair almost anything – this is a common misconception held by homeowners – silicon in the right hands used in the right places is one of the best inventions since sliced bread. However, silicon in the wrong hands is usually used in the wrong places by the inexperienced, further exacerbating roof leaks.
SO I WOULD SAY NO DON’T TRY TO REPAIR YOUR ROOF YOURSELF.
Employ the services of an experienced roofing contractor – if it is a tiled roof employ the services of a roof tiling repair contractor – not just any roof tiler can find leaks, so get an experienced roof tiling repair contractor to repair any leakage to a tiled roof.
With a colorbond or any type of metal roof, look for an experienced reroofing and repair metal roofing contractor. Metal roofs are where I have seen many really bad repairs using silicon by the homeowner. So be sure to employ the services of a metal roof repair contractor for leaks or reroofing.
Then there are companies that do all types of roof repairs and/or replacement. There are many of these type of contractors and this type of contractor are probably your best bet as a common area for roof leaks are where roof tiles meet a metal roof. So their experience in both types of roofing will give best results to alleviate your problems.
How do you find a good roofing contractor – first you find out their capabilities, then you would ask for referrals and remember price should be the last consideration when either reroofing or roof repair, as a good effective roof repairer will save you dollars in the long run. See Blog on this site “Pergola Guttering”.
My answer to your question can I repair my roof myself – no employ the services of the most capable roofing contractor you can find and remember the one that advertisers the most is usually not always the best.