In Earth filling the earth should be free from all roots, grass, shrubs, rank vegetation, brush wood, trees, saplings, rubbish, salt and foreign material/ matter. Earth should be free from stone pieces, kankar etc because these objects hinder proper compaction of soil manually or mechanically. The earth should also be free from salt or kallar and alkaline materials.
Earth brought from cutting should be directly used in filling. Earth should be free from clouds if exist should be broken during lying of earth. At the time of laying/ filling the earth should be laid in regular horizontal layers each not exceeding 20 cm in depth. All lumps or clouds exceeding 8 cm in any direction should be broken. Each layer should be watered and compacted manually with steel rammer or mechanically with ½ tone roller. Where specified every third and top layer should be consolidated with power roller of minimum 8 tones. The top and sides of filling should be neatly dressed.
Plinth Filling or filling under floor:
In case of filling under floor or plinth filling or filling around masonry needs special attention because in these cases one cannot compact/ consolidate the soil with the help of mechanical means i.e. with power roller. Filling under floor or plinth filling or filling around masonry should be similarly done with earth in layers not exceeding 15 cm, watered and consolidated by ramming with iron rammers and with butt ends of crowbars, before the succeeding one is laid. Only sandy soil, free from salts, organic or foreign matter and white aunts shall be used for such filling. Where there is black cotton soil, it shall be removed to a depth of 60 cm as it is liable to absorb moisture and expand thus damaging the floor. The top 30 cm immediately below the floor shall be sand or cinder.
To prevent future sink age and damage to the floor it is necessary, when convenient to do so, that the plinth area is flooded with water for about 24 hours to enable earth filling to consolidate thoroughly. In this case, earth filling should be allowed to dry and then rammed and consolidated, before the flooring is laid.