Roof tiles

Roofs are normally the upper part of any traditional building and are made with roof tile overlapped parallel rows

Roof tiles are designed mainly to keep out rain, and are traditionally made from locally available materials such as terracotta or slate. Modern materials such as concrete and plastic are also used nowadays.
 

Roof tiles use is normally attributed to ancient Chinese and Greeks, who used ceramic plates, thin and minimally curved. But pieces shape and materials have varied according to times, cultures and countries, although their use has remained similar over the centuries.

A roof has two fundamental types of pieces, the pan tile, which collects the rainwater channelling it out, and the cover tile which covers the joint between the channels.

Roof tiles have a large and varied number of shapes including:
Plain and flat roof tiles, laid in regular overlapping rows, Roman (or mixed) roof tiles, that contains itself the pan tile and the cover tile, or curved roof tiles (double tiles, barrelled or semi-cylindrical tiles, mission roof tiles, etc…). 

Depending on the country, the region of the country, the manufacturer, etc… tiles can be named in many different ways.

Names for the roof tiles disposition and collocation over the roof, are also very variable and have changed since the most popular Roman pattern ("Imbrex and tegula", that alternate curved and flat tiles) was designed.