Chipmaster,

Most probably this "problem" is not a problem.

Try this, and do it exactly in this order:
- draw you walls
- insert your doors
- draw your floor

If you do things in this order, the door makes a hole in the wall, and the floor fills half that hole.
If you first draw the floor, and then insert the doors, the floor isn't adapted to the inserted door, and the ground colour or texture is visible.

Hans