Hi @roshanrn,
Thank you for your question about water issues with your garage roof.
Unfortunately, I can see a few issues with this roof that may mean a new roof is going to be necessary.
Firstly, the bowing in the roof sheets makes me think that there might be an issue with the roof framing. If the roof battens were all in line, the sheet would not bow in this fashion. It's likely that the roof battens will need to be replaced in order to fix the bowing.
Secondly, the pitch of the roof does not appear adequate for the water to effectively run off. In metal roofs, the ideal pitch is between 14.5 and 45 degrees. In simple terms, to achieve a 14.5-degree pitch, for every 12 meters of horizontal run, the roof rises 3 meters.
I'm sorry to be the bearer of bad news, but it looks like you're going to need a roofer to fix this issue for you. They will be able to remove the old roof and install a new one that will ensure adequate runoff and weatherproofing for the structure beneath.
Trade pricing is incredibly variable with many things needed to be taken into account. I am not a roofer, but $9k does not sound excessive for this kind of job. I would however suggest attaining a few quotes so you can get an informed decision on pricing
You might like to use a service such as HiPages or True Local to find a some suitably qualified roofers in your area to quote.
Let me know if you have any further questions.
Jacob
