June 2021
I have been able to do additions on a few of them, where you're given an exact number of squares (floor spaces) to add. I was able to add a balcony, a mother-in-law suite (not attached to main house), and an art studio (attached to main house). I am unable to add a level for the "add a level to this home" job. I cannot build up (roof is in the way, and am not allowed to edit the roof) or down - tried adding a basement. I also can't interact with anything in the house, so it isn't just a matter of me trying to renovate the wrong area.
July 2021
Not only couldn't I add the basement, it wouldn't let me add any new walls. I tried going to manage world, but it wouldn't let me add the basement. I couldn't add the basement at all. I also tried to use bb.enablefreebuild but it only took away the cost. I then could only meet the job requirements by adding an additional prebuilt room, attaching it to another room, and replacing all of the items.
June 2022 - last edited June 2022
Fixed in Patch 1.89.214/1.60
If you're still experiencing this issue, please create a new thread.