I found a blender addon today for building houses very rapidly in Blender 2.8+. Here is an example, in Babylon, which I built in <5 minutes:
Notice four windows and a door with an arched top. 400 faces, total vertices = 907, active indices = 1236.
You start with a floor plan, rectangle, H-shaped, random seed etc.You then add floors, windows, doors, steps roofs and balconies by selecting one or more faces in edit mode then pressing the appropriate button (See image below)
So instead of doing a lot of boolean cuts - just a simple one button click. And you can build from single-storey to skyscrapers. (The floor plan can be a circle - so possible to build castle towers ?)
As you add parts, they have defined material zones which are easy to convert to materials themselves. (See attached image). Still have to add UVs for textures though.
It is still in alpha, but it seems to work fine … so more features to come, shops, garages?
Stay Safe, gryff