The main cornerstone of design is 1. the budget 2. site constraints 3. planning law 4. aesthetics. It is with this in mind that we finalised and submitted for planning application. In order to submit the application I also needed to engage an Engineer to do soil test for percolation area for septic tank, and to take site levels so as when I was drawing cross section of site we could see how well the dwelling would nestle into the surrounding undulations.