Section 2(57) in Tamil Nadu Combined Development and Building Rules, 2019
(57)"Height of the Building" means the height measured generally from the formed ground level within the plot abutting the road or passage excluding ramp if any within the plot up to to the roof level of the topmost livable floor. In the case of pitched roof, height of the building means the height measured from the ground level stated above up to the point where external surface of outer wall intersects the finished surface of the sloping roof, and in the case of gables facing the road, the midpoint between the eave's level and the ridgeExplanation. - Stair-case head rooms, lift rooms, solar panels, elevated tanks and also water closet (with floor area not exceeding 10sq.m.) above topmost floor, and also architectural features, and parapet walls of height up to 1.5 meter shall not be included in calculating the height of building. In cases where earth filling is made or proposed within the site above the average level of the abutting street or road, then the height of building shall be reckoned from the filled up ground level around the building provided such filling does not exceed 1 meter above the average level of the abutting street or road;
