Slates ~ slate is a natural dense material which can be split into thin
sheets and cut to form a small unit covering suitable for pitched
roofs in excess of 25°pitch. Slates are graded according to thickness
and texture, the thinnest being known as `Bests'. These are of 4 mm
nominal thickness. Slates are laid to the same double lap principles
as plain tiles. Ridges and hips are normally covered with half round
or angular tiles whereas valley junctions are usually of mitred slates
over soakers. Unlike plain tiles every course is fixed to the battens
by head or centre nailing, the latter being used on long slates and on
pitches below 35°to overcome the problem of vibration caused by
the wind which can break head nailed long slates.
Typical Details ~
Roof Slating