A fiberglass mat core with asphalt around it and grit stuck in the asphalt on the top.
A fiberglass mat core with asphalt around it and grit stuck in the asphalt on the top.
And the person who found it isn’t doing a good job either, putting new shingles over old. The old should be removed.
Tiles are great, I’d love to have a roof last 100 years. But they don’t get as much use here because of issues with ice damning up the bottom edge and pooling water up under the tile, which then freezes and expands and dislodges or damags the tile. That can be overcome, but it’s easier and cheaper to use shingles.