Roof tiles are designed mainly to keep out rain, and
are traditionally made from locally available materials such as clay or slate. Modern
materials such as concrete and plastic are also used and some clay tiles have a waterproof
glaze.
A large number
of shapes (or "profiles") of roof tiles have evolved. These include:
- Flat tiles - the simplest type, which are laid in regular overlapping rows. This
profile is suitable for stone and wooden tiles, and most recently, solar cells.
- Imbrex
and tegula, an ancient Roman pattern of curved and flat tiles that make rain channels
on a roof
- Roman roof tiles - flat in the middle, with a concave curve at one end
at a convex curve at the other, to allow interlocking.
- Pantiles - with an S-shaped
profile, allowing adjacent tiles to interlock. These result in a ridged pattern resembling
a ploughed field.
- Mission or barrel roof tiles are semi-cylindrical tiles made by
forming clay around a curved surface, often a log or one's thigh, and laid in alternating
columns of convex and concave tiles.
Roof tiles are 'hung' from the framework of a roof by fixing them with nails. The roof tiles are usually hung in parallel rows, with each row overlapping the row below it to exclude rainwater and to cover the nails that hold the row below.
There are also roof tiles for special positions, particularly where the planes of the several pitches meet. They include ridge, hip and valley tiles. |
