Board Thread:Skyrim/@comment-104.162.213.2-20150701214544/@comment-6881629-20150702105712

The bugs list does say some of the floor may be missing you could try Whirlwind Sprint or something similar to dash over it or save quite and reload to refresh the area, don't know it they'll actually work though.

On a PC the command TCL (all caps and type it again to turn it off) will let you float over.