For some reason when deleting the foundation for the apartment I am working on, not all the floor tiles have deleted.
Never had this problem before and have no idea how to fix it, I tried using 'moveobjects' and the sledge hammer and putting the foundation back and deleting it on its own but it hasn't worked, anyone else experienced this and know how I can fix it?

Did you put something above that area, if so then that is why.

The hammer tool will take care of it is needed.

some things to try::
-the constrainfloorelevation cheat with or without the moveobjects cheat.
-other Build Mode tools around the area; with or without cheats.
-change zoning then try deleting again; if occupied, evict all tenants first. may afterward change zoning back regardless of the result.
-the Lot Adjuster program; though I am not sure which options in that program would help.
-Pescado I take made several hacks that can remove stuck stuff.

Thanks for the tips, sadly everything I tried failed, I had a sim move on to the lot and then killed him off once he did I could just delete the floor.