It's a ritual spell, it takes five casters, and it consumes the silver thnickels. Most wizards get it at level 8, but if you take ritual casting or specialize in houseromancy you can get it as early as level 4.

I think they might be stupid enough to believe that the value of the house is less silver than was given to sell out a certain heretical carpenter. And that's the kindest reading I can give it.