You should always check with your council, but generally you will need a building consent for any building with kitchen or bathroom facilities. A building under 30m2 without kitchen or bathroom does not need a building consent, but if over 10m2 (such as our tiny cabins) restrictions apply, eg required to be built or overseen by a Licenced Building Practioner. Decks more than 1.5m above ground level require consent. Structural buildings such as verandas may require consent.