Build stairs through foundations.
Sims 4 delete floor under stairs.
Then remove the wall that holds that room together.
From there click delete ceiling.
Gone are the days of having to demolish and rebuild your house if you forget to lay down a foundation.
Once selected just move the staircase around until it s in the correct location and click to place.
In the sims 4 you re able to adjust staircases dynamically.
As i can recall this have been really easy to achieve in previous versions of the sims.
From there delete the 3x2 tiles on top of the basement.
You should then have the floor from the new space you drew as well as the deleted floor so you can see to the first floor below.
It will turn yellow click to delete it we are then left with a hole in the floor where the stairs are.
I had to build fences round the stairs which is really strange looking when there s nothing holding up the fence.
Now that you have an open pit on your lot that you can fill with grass place some planter boxes and you re all set.
The floor on floor one needs to be deleted select the sledgehammer tool at the top and hover over the floor on floor one.
If you want wider stairs select the placed stairs and grab the side arrow and pull out or to the desired width.
The game will remove any extra flooring for the wider stairs or add flooring if you make wide stairs narrower.
That looks like the ground floor you re trying to delete so simply make a basement room sized 3x2 under the staircase select the room then go up a floor where you will see the yellow outline of the basement room.
But now i had a really hard time removing the flooring on the second floor to get the open space i wanted.