Section 10(10) in Tamil Nadu District Municipalities Building Rules, 1972
(10)For a roof the plane of which inclines upwards at a quarter angle than 20 degrees with the horizontal, the superimposed load, which shall, for the purpose, be deemed to include wind pressure or casual load, shall be taken at 48.824 kgs/ square metre of sloping surface normal to such sloping surface on either side of such roof.
