While trying out an issue another player had: Workers wont start building a building and I come across another issue. Make this:
Basically a foundation, auto-wall it and then use the upper flooring tool (highlighted green in the building designer).
Done that? Now auto-wall a first floor onto it. Like so…
This would create an open interior tower, yes?
Now try and add windows to the 1st floor, if you can without a big red X, you might see the window but a wall runs through it.
Took a while, but I figured out that the game code can’t determine which is the exterior of the building so places 2 over-lapping walls, hence the blocked windows. The walls also get constructed over each other, double material cost. To get around this all you have to do is make a complete floor in between.
To make it back into an open interior, start construction and when the workers start digging out the foundations, edit the building (pausing handy) and use the eraser to take away the floor before it gets built. Not the edge though or it makes the building look like a weird hourglass.