Replacement ceramic tiles must be rehung with straps attached to the back of the tile. Do not use exposed strap hangers - they make the roof look ugly. The copper strap shown below can be altered to fit almost any type of ceramic tile, including Spanish tiles. It's a good idea to put a dab of silicon between the copper and the tile to glue it in place.

The illustration below shows the back side of the tiles and how the tile hook holds the tile in place. Tiles are usually loose enough on the roof that you can slide the tile and hanger in place without any problem. The replacement tile hooks on the existing tiles.

When the job is done, there is nothing visible on the surface of the roof that shows a repair was made. For sources of replacement tiles that will match an old roof, go to my tile source page.