The magical properties of spikes is in their function as anchors, the time they have spent fulfilling this mission, and the fact that they are made of iron.
Cold iron repells negative energy. And at a grittier level, there is a belief that ghosts or spirits cannot cross iron, so many old cemeteries were built with iron fences around them. Wrought iron around family burials and mausoleums may have been placed for the same purpose - basically to keep the peace.
If you own or rent a home, you can perform a ritual using railroad spikes to anchor yourself on the property - that is, ensure that you will not be foreclosed on or kicked out by a landlord. (Any responsible wizard would tell you, of course, to do this ritual in conjunction with paying your bills and not tearing holes in the walls.)