When you set a boundary, you have to set consequences along with it, or else the boundary is meaningless and only serves to reinforce that people can treat you any way they please.
That's why it's good to set small, manageable ones. In your case, I'm not sure what that would be. Smoking crack in your house, or even BRINGING it into your home, puts you at risk of arrest and worse. So I'm not sure what to say.
Wishing you luck with this. I cannot live with someone who is in active addiction, and I'd walk out in a flat minute (or have him arrested) if someone overstepped my boundary that you "don't do crack in my house", so I can't be much help at all. But I'm sending you hugs and strength to figure out what kind of life you really want, and start heading in that direction.
GL