A few weeks ago I noticed a discolouration on my bedroom ceiling. I had a fleeting thought of water damage and then promptly forgot about it. Another week passed, with plenty of rain, and I noticed the discoloured patch growing in size and getting darker.
I had my roof repointed and gutters replaced fairly recently (within the last 2 years) so the next viable explanation was a cracked roof tile, and judging by the location, I guessed that the brackets holding the solar panels were to blame.
I called my handyman and explained the situation. He said it could only be a handful of things, and either way he'd be able to help. A quick exploration in the roof revealed exactly what I had thought: a cracked tile under the brackets holding the solar panels. He guessed that it was likely cracked at the time of installation, but may have moved recently to widen the crack and allow water to penetrate. I suppose that is the risk you take when something is screwed into a terracotta tile.
We waited for a couple of dry days to let the crack dry out, and then he filled the crack from the inside with silicone. This was the best solution as the cracked tile was under the solar panels, and therefore inaccessible from the outside. This is not a permanent solution, and will likely require the same treatment in a few years as the silicon can degrade over time, especially if it is exposed to sunlight.
Seriously, a good handyman is a godsend - they can do most things and don't charge ridiculous prices. In fact, I'm still waiting for him to send me the bill, which is all of $25.
To ensure the repair was working, I drew a pencil mark around the stain and monitored it in the following weeks (in which we've had plenty of rain). The stain hasn't worsened in colour or size, so I think I'm in the clear. The handyman was quite impressed with my idea of drawing around the stain, which I got from seeing medical shows where they will draw around a rash to monitor whether it is spreading and how quickly!
So the next step will be to prime and paint over the stain, and hope that it blends with the rest of the ceiling so that I don't have to repaint the entire ceiling!