How to layout a foundation (techniques) 

The main issue with laying out a building by using this method is that the stakes will be either removed completely or at least moved during the excavation process. So in other words it only works for the excavation. The lines will need to be reestablished for building the foundation walls. Setting up batter boards back from the actual wall lines eliminates this issue. In this case the fences could have actually been used for at least some of the batter boards, just nails driven into them at the proper height and locations.