Roof tiles have been designed primarily to keep out rain, and they are traditionally made from locally-available materials such as terracotta or slate, although modern materials such as concrete and plastic are also used and some clay tiles have a waterproof glaze. Numerous shapes (or “profiles”) of roof tiles have evolved.These include:
Imbrex and Tegula
Mission or Barrel Tiles
Interlocking Roof Tiles
Flat tiles are the simplest type, which are laid in regular overlapping rows. Flat roof tiles are most often made of clay but may also be made of stone, wood, plastic, concrete, or solar cells.
Imbrex and tegula is an ancient Roman pattern of curved and flat tiles that make rain channels on a roof.
Roman tiles are characterized by an appearance which is flat in the middle, with a concave curve at one end, and a convex curve at the other, to allow interlocking.
The S-shaped profile of pantiles allows adjacent tiles to interlock, which results in a ridged pattern resembling a plowed field.
Mission or barrel tiles are semi-cylindrical tiles laid in alternating columns of convex and concave tiles. These were originally made by forming clay around a curved surface – often a log, or the tile maker’s thigh. Modern-day barrel tiles are mass-produced from clay, metal, concrete or plastic.
Interlocking roof tiles are similar to pantiles, with the side and top locking for improved protection from water and wind.
Antefixes are vertical blocks which terminate the covering tiles of a tiled roof. Roof tiles are “hung” from the framework of a roof by fixing them in place with nails. The tiles are usually hung in parallel rows, with each successive row overlapping one below it, to exclude rainwater and cover the nails holding the row below. There are also roof tiles for special positions, especially where the planes of several pitches meet. These include ridge, hip and valley tiles, and can either be bedded and jointed in cement mortar or mechanically fixed.