This section is fairly easy. The first step, is to create a save file. You wont have to build anything, however you should purchase the empty plot you wish to modify. I highly suggest that you do not build until after you've completed this guide. Once you've done this, quicksave, and exit to the main menu. From here you can click "load game" which will bring up a menu of your save files in game. Click the button in the top left of the pop-up menu to browse the local save files. Now simply open the file you wish to modify in notepad and move to section two.

Now that you've opened your file in notepad, you will notice several lines of configuration data. Next, locate the name of the plot you wish to modify. If you haven't built anything yet in this save, this will be found within the first two lines. Next to the name of the plot is a data set clearly labeled as the Height limit. The X data should be 0, and the Y data will be the current floor limit. Modify the Y data to your preferred value and then save the modifications you've made before you close notepad. Now use the already opened menu to load the file you just modified, and the height limit on your selected plot should be at your desired limit. If this causes any in game issues, the solution is simple, delete the save file. I strongly recommend you not exceed 15 floors unless you have a relatively high end PC.