Pool builders in Martinsburg usually charge clients per square feet of the water surface area. A typical round swimming pool that has a diameter of 19’ and 3’ deep with a water surface area of 283 square feet will normally require a two-man installation team. The usual labor cost per square feet is around $9. The total pool builder labor cost for this pool will be around $2500 with a total time of 40 hours or 2. 5 days. The labor cost a pool builder may charge also varies depending on the size of the pool, the depth, and the design.