Player should be able to build on object where it is not actually possible. What do I have to set?

Hello, I would like a player to be able to build on a lava tile but I don’t know how to set this or if it is even possible. Maybe someone can help me and explain, if it works, how it works.

Thanks in advance for the answer!

Try in the tiles Attachment>Building Attachment Slot and set it to Slot Floor.
Is your tile aligned to the player build grid ?