House Elf-krafter förklaras inte någonsin direkt i böcker eller JKR-material.
Men eftersom ingen magisk användare kan uppträda in / ut från Hogwarts (eller Voldemorts grotta) och älvor kan, kan det utgå ifrån att deras makt inte lärs av guider ursprungligen.
JK Rowling replies -> He's a house-elf, they've got powers wizards haven't got (but wizards have also got powers that house-elves haven't). (source: JK Rowling's World Book Day Chat, March 4, 2004)
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Q: You say that people cannot Apparate or Disapparate within Hogwarts and yet Dobby manages it, why is this?
A: House-elves are different from wizards; they have their own brand of magic, and the ability to appear and disappear within the castle is necessary to them if they are to go about their work unseen, as house-elves traditionally do (Source: http://www.jkrowling.com/textonly/en/faq_view.cfm?id=73 )