A new Italian piling system known as the root pattern method is finding wide acceptance in Europe, chiefly for underpinning existing buildings during new construction. The system causes no vibration and requires no staying operations, soil digging or cutting through walls. The root pattern piles are formed by a special high speed rotary drilling rig that drills through existing concrete or masonry into the underlying ground until an appropriate depth is reached. At the same time a steel casting progressively follows the drill to prevent cave-in. Depending upon the nature of the soil and water conditions, the drilling continues by air or hydraulic action or mud drilling. When drilling is complete, twisted steel bars are inserted as reinforcement for the full length of the hole. A coarse sand/cement mix is then placed and compacted under the action of compressed air while the casting is steadily withdrawn. Workability agents are added to the mix to ensure that it will flow and penetrate adequately into the surrounding soil under the air pressure. The actual pile, therefore, has an effective diameter much larger than the size of the casting.