Two common causes are settling of the building and water damage to the surface beneath the tiles.

Settling of the area began in the mid 1970s.

They settled in an area just north of the mill now known as Maillardville.

They should settle, of course, but apple's probably being unreasonable.

And I have a score to settle of my own.

Settling of ferro-particles can be a problem for some applications.

Those are primary plants, which means they provide settling and skimming of waste water.

The males generally fly high up, often around a selected tree, where they can be seen settling now and then well out of reach.

However, it was occasionally still used to settle arguments "of honor".

He'd settle, of course, for the second spot on a national ticket but that's looking unlikely as well.