As you are responsible for repairs and maintenance, I think you are lucky the OC didn’t hit you up for the cost of re-waterproofing your portion of the space.
Responsible for repairs and maintenance of what? If the relevant by-law doesn’t state that the lot owner is responsible for the common property, then the OC should compensate them for the destruction of the tiles required when the common property roof was re-sealed. I’d be taking that one to Fair Trading and the Tribunal. I have responsibility for my bathroom tiles but if my OC wanted to dig them up for THEIR purposes, I’d be looking for a reasonable pay-out.