1.Crack and leakage condition inspection
Check the process procedure after finding the thickness, width and depth of crack and leakage condition of the structure
2. Drilling Operation
Drill directly into crack section if the thickness of concrete is thinner than 10cm. For the thickness of 10cm~50cm, drill it with 45 degree angle by keeping a distance of 1/5 of concrete thickness. Make sure it penetrates the crack section. If the thickness is over than 50cm, keep the distance of 20cm~30cm and drill it with 45 degree angle until it penetrates crack section. And keep drilling by maintaining the fixed interval.