I am doing an owner/builder pool. The shotcrete company I hired left an approximately 4 x 4 in. (102 x 102 mm) hole in the deep end of the pool on the side wall. What is the proper way to patch this hole prior to plastering? (The shotcrete was applied a month ago.)

The normal repair is to pressure wash with at least 3000 psi (21 MPa) of water pressure to remove any dirt and laitance on the surface of the concrete. Given the rather small size of the hole, it can be hand-patched with a nonshrink hydraulic cement with at least 4000 psi (28 MPa) 28-day compressive strength to plug the hole. After the patch is completed, roughen the surface that will receive the plaster.