This is a very old house. Made right after multi storey got implemented. It has serveral floors. 3 to 4 to be precise. I want to "redecorate" it and was trying to remove the ceiling on the 1st floor. I was able to destroy the floor but not the floor plan that remaind. I received the message that i cannot remove the tile, it would cause a collapse. Then i tried to remove the tile on the second floor. Same message. Even wenn i tried to remove the actual roof tile/roof plan it got the same message. So i cannot remove any floor tile or roof tile in this house. Is this a bug? Is there a way around that. I do not want to destroy the complete building. But as of now i cannot see how to do it but to rebuild the complete house.