Problem with the Now Century Manor

I had purchased the Then and Now Century Manor ages ago and just got around to playing with it. I wanted to have my sim renovate the Now Manor as part of my game, but I'm running into a huge problem. In the Now Manor, there are these triangle tiles on the ground, parts of the "roof" or "ceiling". I can't delete them, move them, or do anything with them. One was blocking a doorway from the sunroom to the outside and I had to delete the door instead. I've tried MOO, but that wouldn't do anything either. How can I get rid of them? I can't renovate the manor if I have these tiles still on the ground. I thought part of the idea of getting the decrepit manor was not only the "scare" factor but to maybe have a sim recreate the glory days ala house flipping.