Unfortunately, I don't think so. Your comment implies you already know about #BuildNewcrest, so I don't know much advice I can give you. You could make your own fresh save file filled with houses, and then use save as to basically create "new" games copied off of that one world; nothing's happened with the file yet, but the houses are still there. You'd still have to add the houses the first time, but you'd only have to do so once and not every time you open a new game.