Safety is key when planning to remove an existing structure.  Prior to machinery showing up to demolish any existing structures, the power supply to the structure must be disconnected.  This means more just than tripping a breaker.  The physical line must be pulled away from the building so the excavation crew does not damage it.  The building must also be emptied.  Most landfills will not accept mixed debris, meaning debris other than the building itself like bikes, household trash, lawn mowers, toys, and even light bulbs.  Hazardous waste must also be properly disposed of by the homeowner.