It’s unlikely to be damaged in ways that are non-visible or intangible. It is possible to live with severe household problems for several years, without being affected in the course of their lives. The roofing company might have stories about people trying something similar with the roofs on their homes. This situation may not be more dangerous, if you require the assistance of a professional to fix your garage’s roof. However “Repair the Garage Roof” is just one aspect in a much larger house improvement plan.
An issue where “roof has a leak after the an upgrade to the roof” could be much less likely if you’re focusing on changing the garage roof only. These roofs won’t be very massive. They can be handled by experts without having to worry about how your garage may appear like. This will make it easier to do the job. If this isn’t your roof that you depend on daily, your “roof restoration vs. replacement” argument will be distinct. What caused damage to the roof of your garage could have caused similar harm to roofs of other structures.