4.1 Footing depth and spacing When footings are to be placed adjacent to an existing structure,the line from the base of the new footing to the bottom edge of the existing footing should be 45 or less with the horizontal plane. From this requirement it follows that the distance m should be greater than the difference in elevation of the two footings,Z. If the new footing is lower than the exiting footing,there is a possibility that the soil may flow laterally from beneath the existing footing. This may increase the amount of excavation somewhat but,more importantly,may result in settlement cracks in the existing building. 4.1 Footing depth and spacing ▪ When footings are to be placed adjacent to an existing structure, the line from the base of the new footing to the bottom edge of the existing footing should be 45°or less with the horizontal plane. ▪ From this requirement it follows that the distance m should be greater than the difference in elevation of the two footings, zf . ▪ If the new footing is lower than the exiting footing, there is a possibility that the soil may flow laterally from beneath the existing footing. ▪ This may increase the amount of excavation somewhat but, more importantly, may result in settlement cracks in the existing building