A method and apparatus for creating a through-hole in a building structure includes selecting a first location on a first side of the building structure that will define a first opening of the through-hole; disposing a magnet at the first location; selecting a second location on a second side opposite the first side via a magnetic pointer magnetically pointing to the magnet; and drilling the through-hole from the second side through the building structure in a direction indicated by the magnetic pointer creating the through-hole defined by the first and second openings on the first and second sides, respectively.