I have been advising a few clients lately to make space at the rear of their properties to fit another dwelling in the future. Some of our clients have been a little tight for finance lately to complete a two home build with their knock down rebuild project. 

So my advice was to build one home as close to the front boundary with enough space for a rear access driveway for easy second home access. By doing several simple items now, it will make the build of a second home less expensive in the future.