Tired tiles

Some years ago, we discovered an old newspaper left under some floorboards, we assume, when our house was built, c. 1900. Some 114 years later, much of the house remains unchanged, but some parts are showing their age.

Looking at the roof tiles outside my office, for example, some tiles have slipped and more than a few have started to sprout moss, but we remain waterproof nonetheless (just as well, today was a day of downpours and drizzle).