The earth filling in under the floor in layers should not exceed 15 cm. It should be watered and consolidated by ramming with iron rammer. Only sandy soil free from salts, organic or foreign matter and white ants shall be used for filling. The earth should be free from all roots, grass, shrubs, vegetations, bushes, wood, trees, saplings, rubbishes, salt and foreign matters. All lodes of earth shall be broken. Where there is a black cotton soil, it shall be removed up to the depths of 60 CM because it is liable to attain the moisture and expansion and thus damages the floor.