Guides · 5 min read
Expanding home or kitset granny flat: which should you build?
We sell both, and we will tell you straight which one we would put on your section, including when it is the other one. The decision rarely comes down to taste. It comes down to access, timing, size and how much say you want in the layout.
How they differ
An expanding home is a steel framed unit built and fitted out in the factory. It ships at shipping container width, is craned onto foundations, and the side sections fold out to roughly three times the travelling width. Kitchen, bathroom, wiring and plumbing are already in. It is a finished home by the end of the day it arrives.
A kitset granny flat arrives as panels, framing, roofing, joinery and fit out, and is set up on your section by licensed builders in about a week. It is a conventional timber or steel framed house, just made faster and more precisely because the parts come from a factory.
Choose an expanding home when
- Speed matters. Watertight and lockable the day it lands.
- The budget is fixed and tight. Fewer trades on site and less time means less to go wrong.
- It is a rental and the return per dollar is the point.
- You may want to move it one day. It can be folded and relocated.
- A truck and a crane can reach the spot. This is the deciding question on most sections.
Choose a kitset granny flat when
- Access is tight. Rear sections, steep drives, and anywhere a crane cannot lift a container sized unit.
- It is for family to live in permanently. A kitset is a house, built like one, and feels like one.
- You want a say in the plan: move a wall, change a window, choose a cladding.
- You want the cleanest fit with the 2026 exemption. A timber framed kitset with standard cladding sits squarely inside the conditions, which is why our three Haven designs are the ones we lead with.
- Resale value matters. A conventionally built dwelling with a full document pack is the easiest for a valuer and a buyer to understand.
A word on consent
Under 70m² and inside the conditions, a kitset granny flat can be built without a building consent. Expanding homes use sandwich panel walls, and MBIE's guidance suggests panelised construction may need the ordinary consent route even under 70m². Our 40ft model is 76m², so it always needs one. We confirm the pathway for your address at the site check, before you commit, and handle whichever applies.
There is no wrong answer here, only a wrong answer for a particular section. The free site check is where we find out which is which.
Updated 24 September 2026.