When I move the wall to the corner......it is not exact. Maybe I describe what I want to. I want to create a blueprint of the flat - walls, surface, area of the floor with cote. It is enough for me.

So you recommend me.... paint walls with my thickness and after that create a room? Can you recommend any video with basic creating room and wall?

Hi, I'm a newbie and would need an explanation of drawing walls and surfaces.
I draw the surface of a room and I want to draw the walls but with different thicknesses. When I change the thickness, the floor creeps into the wall. Then I get different dimensions and room area. Where am I going wrong ...