[RESOLVED NOT A BUG] Significant building error

Sorry, my bad English.
If you have already used add new floor
Later building on the lower floors, high floors will not appear floor.

I don't think that this is bug. Upper floors can have different shape as lower floors. E.g. upper floor can be on pillars and there is no foundation on lower floor.

Hello well actually this is not a bug. Every floor could be modified separately apart form other floors. so in this case if you add new foundations to existing ones in one floor, the thing that you need to accept is that this change is not made on the other floors. So to fix your visual experience you need to add the same foundation are on the upper floor - then you cam modified it by creating room, or you can also delete made foundation creating roofing.

Ok, I found a solution Build foundation here