Objects glitching at basement level

Hi, so for a few months now I've had this issue where certain things do a flickering glitch when in basements. I have cc and mods installed but the glitching seems to occur with and without them. It isn't everything, most stuff is fine but some overhead lights, railings, stairs and assorted other stuff does this. Let me know if there's anything I can do about it, it's really bothersome, thanks!