Roof coverings for vernacular buildings

The figures below are based on current architectural figures.

A critical figure is the gauge or batten centres. The battens are used to support the tile or slate and they are spaced differently depending on the overlap required. For instance plain tiles require a lot of overlapping to keep the rain out, so the gauge is only 100mm. Because the tiles are around 265x165 the overlap gives you a thickness of 3 tiles at any point in the roof. This makes this a very heavy roof covering, around twice that of thatch.
In cases where the top of rafters can be seen, such as junctions between roofs, the batten centres together with roof pitch may be helpful in indicating the previous roof covering.

Plain tiles

Minimum pitch 35deg
Gauge 100mm
Weight at maximum gauge 77Kg/sqM


Minimum pitch 22.5deg
Gauge 315mm
Weight at maximum gauge 42Kg/sqM

Double Romans

Minimum pitch 17.5deg
Gauge 343mm
Weight at maximum gauge 45Kg/sqM


Recommended pitch 50deg
Minimum pitch 45deg
Maximum pitch 60deg
Weight approximately 34Kg/sqM

Thatch - water reed

Thickness 300mm
Battens 255mm

Thatch – combed wheat reed

Thickness 300-400mm
Battens 150-230mm

Thatch – long wheat straw

Thickness 400mm
Battens 150mm


Minimum pitch 22.5deg
Sizes vary considerably from Princesses at 610x355, with a gauge of 280-255mm to Ladies at 405x205, with a gauge of 177-152mm.
Thickness varies from 4 to 6mm with weights 31-40Kg/sqM

Corrugated iron

Invented by Henry Palmer developed by 1829 and zinc coating process patented in 1837.
Several manufacturers producing by 1840. First used on a roof in 1843 extensive use by 1850
By 1861 noted for its cheapness for farm buildings. Originally wrought iron and from 1890 was replaced by mild steel.