Glitching through ceiling when spawning blocks under the player

In a magic based game I am using a somewhat unconventional flight script that works through spawning invisible cubes under the player and destroying them soon after. The only problem with this is that it causes the player to glitch through the ceiling of the chamber. In what ways can this be avoided? I was thinking of finding a way to test distance to the ceiling, but I am unfamiliar with how to do this. I am also open to other suggestions.