Conference Call- Google Imagery comment, page-22

About a dozen years ago, I helped my brother to put fiberglass-based asphalt shingles on a roof for an extension he had added to his house in Flagstaff Arizona. I was surprised not to see tiled roofs in Flagstaff. My brother told me that tiles absorb moisture, then disintegrate when the water friezes in winter. For the same reason driveways are made of air-entrained concrete that provide tiny chambers for water to expand into when it freezes.

In the USA it is not unusual to reshingle roofs after twenty years, because if one lets a problem develop and the underlying plywood is damaged, it costs much more to fix, whereas simply slapping down new shingles is fairly inexpensive. Laying new shingles is easy, except that roofs in the USA and Canada usually have a steep pitch to allow snow to fall off, which makes them dangerous for home-owners to to tackle. Consequently, roofing service companies with the right equipment and safety experience thrive, and many are large companies.