Class 4 dwelling (NCC)
A Class 4 dwelling is a sole residence within a Class 5-9 commercial building (a caretaker's flat above a shop), with residential amenity and fire requirements.
Ask Chalkline about this →A Class 4 dwelling is the NCC classification for a sole dwelling within a Class 5 to 9 commercial building, for example a caretaker’s or shopkeeper’s flat above a shop. It carries residential amenity and fire requirements distinct from the commercial parts of the building.
The NCC classifies buildings (and parts of buildings) by use. Class 4 is the odd one out: it is the only residential use allowed within an otherwise commercial building, and there can be only one Class 4 part in a building. The classic case is the residence attached to a business, a flat over the shop, a manager’s quarters in a motel (Class 3), a caretaker’s dwelling in a warehouse (Class 7 or 8).
Because someone lives and sleeps there, the Class 4 part has to meet residential-style provisions that the surrounding commercial space does not: the amenity requirements of a habitable dwelling (ceiling heights, light, ventilation), smoke alarms, and fire separation between the dwelling and the commercial use below or around it, so the occupants are protected from a fire that starts in the business.
For a builder the practical points are to recognise when a project creates a Class 4 part (any time a single residence is built into a commercial building) and to treat that part to residential standards plus the fire separation from the commercial use, not as just another office or storeroom. A common change-of-use scenario, putting a flat into a warehouse or above a shop, creates a Class 4 part and triggers those requirements. Confirm the classification with the building surveyor, because getting it wrong means either over-building the commercial space or under-protecting the people sleeping in it.
Also known as: Class 4 part, residence in a commercial building.
Category: Building / Classification.
Related
See also
References
- NCC building classes (Chalkline) (verified 2026-06-01)
Last updated: 2026-06-01. Verified: 2026-06-01. Quarterly review for currency.