@Unforgettable33 If I am understanding correctly what you want to do, no, just deleting flooring is not an option. When you create a room the "Construction Quality Concrete" floor is created by default, along with walls that have the "Drywall" wall covering and a ceiling is built. The wall itself costs money, and it costs money to build each area/square of the room, but the actual floor tile "Construction Quality Concrete" and the "Drywall" wall covering added by default when built are both free (Cost = $0). If you want to change one or more tiles just select the floor covering you want to replace and do so in the manner I mentioned in my first post. If you want to go back to the "Construction Quality Concrete" for the area you do so not by deleting the new flooring you added with the sledgehammer but by replacing it. If you like you can replace it with "Construction Quality Concrete" at a cost of $0.
(Note: You can use the sledgehammer to delete a floor tile that is directly placed on the ground with no foundation, though.)
In Sims 4 adding flooring/ceiling above an area you want columns around that currently has no flooring/ceiling above it:
- First, make sure the area you want the ceiling/roofing over is being considered a room by the game. You can do so my tracing the entire area with the wall tool, or by using the room tool. When you have completed the room the game will create a default floor and ceiling. You can then use 'control + wall tool' to drag over each wall you want to delete. There will be a ceiling left above it now and you can add a roof or go to the next level up and add flooring (& and fencing if you want) to that area. It should now function in the way you want with columns added.
- If you have a room with no ceiling, you try several things to create the ceiling. Click on the room's wall and see if the whole room highlights.
- If the room does highlight when a wall is clicked, leave it highlighted and go to the floor above and click the yellow rim on that highlighted room and choose 'build ceiling'. You should then be able to proceed as above.
- If the room does not highlight when a wall is clicked, re-trace the entire room with the wall tool in the manner mentioned above to complete the room and the game should create your floor and ceiling when you have finished tracing the entire perimeter of the room. You should then be able to proceed as above. - Workaround: If you have an incomplete room with no ceiling you may or may not have other touchy issues with it later if you don't complete the room as above, but if you go to the floor above and create a room that covers the entire area this should also provide a way to delete those walls (as mentioned above) and leave that flooring above the room below and add your flooring tiles to that, and add your columns to the area you wanted.
Hope this helps. Let me know if this did or did not address your issues. I'm happy to clarify further if needed.