ACI 506R-05, “Guide to Shotcrete,” Section 5.6, on Alignment Control (refer to ASA Bookstore: gives specific guidance on proven methods to establish the line and grade of the surface, as well as proper material thickness and cover. Common methods are use of ground wires, guide strips, depth gauges, and depth probes. Please refer to “ASA’s Buyers Guide” ( and contact one of our members who provides supplies to the shotcrete industry