Voids in grouted masonry walls can be located using impulse radar testing and a fiber-optic borescope. Using these two testing methods, engineers are able to determine the exact location, size, and shape of the voids. First the engineers use the impulse radar apparatus to scan each core designated to contain grout. At each void found by impulse radar, a 1/2-inch-diameter hole is drilled and a fiber-optic borescope is inserted. Looking through the borescope, engineers can see the size and shape of the voids.