So, I have a video tutorial on this and I never got around to making a full out written tutorial. This is a VERY simple thing to do, but in order to do so your game has to be patched to 1.7.9 or higher. This is when the basement tool was introduced. Again, in nice big bold words:
YOU NEED PATCH 1.7.9 OR HIGHER!
This tutorial can be applied to different ideas, like to line driveways, split levels...other stuff