But the landlord wanted it gone, saying it was put there without their approval, or that of the council, and posed a "substantial health and safety risk".
In a recently-released decision, the Tenancy Tribunal found in the landlord's favour and gave Constable 90 days to remove the cabin. She must also remediate any lawn damage it might have caused.
The Tribunal said the case raised "novel and quite complicated issues" such as whether the cabin was a "vehicle" or "building" for the purposes of the Building Act 2004 and whether certain sections of the Residential Tenancies Act 1986 (RTA) applied, including whether the cabin was an unapproved fixture made by the tenant, whether the landlord was unreasonably withholding consent it, and whether it could be categorised as a minor change to the property.
The cabin has a floor area of about 12.5m2 and a deck of about the same size. It has wheels but was transported to the property on the back of the truck and lifted off with a crane.
The exterior is durable ply cladding with aluminium joinery and a house-type guttering system.
Constable installed a heat pump in it and connected the cabin to the house's electricity supply. But there is no water supply to it so its kitchen and bathroom sinks, and toilet were unusable.
In evidence to the tribunal, Constable said she didn't tell the landlord about it at first but forewarned him ahead of a property inspection a couple of months later.
She said the property manager who conducted the inspection agreed the cabin could remain for six weeks but the same day (possibly after consulting the landlord) issued a 14-day notice for it to be removed and described it as a "tiny house".
Constable said she responded with an email a week later saying she had tape-recorded the property manager's consent to the cabin being there for six weeks. Even so, she now wanted to keep the cabin indefinitely as her son had moved into it.
She offered to pay an extra $50 weekly in rent.
In legal submissions on her behalf, an advocate said, "The sleepout falls under the definition of a minor change under section 42B(2) of the RTA as it is an addition to the premises".
It was not a fixture, but a vehicle that was not immoveable and therefore not a "building" as discussed by various decisions.
Counsel for the landlord submitted the cabin was a building – not a vehicle. The parts of the RTA that provided for minor changes were not intended to include an additional bedroom.
The cabin required a building consent as per the Building Act.
Tribunal adjudicator Robert Kee considered case law and the legal definitions for a building and a vehicle before deciding the cabin was a building.
As such it was a "fixture, renovation, alteration, or addition" under relevant parts of the RTA, he said.
But as a building it was not a minor change and relocating it required building consent.
Even so, it could still conceivably be argued that the landlord was unreasonably withholding consent for the cabin, Kee said.
Considering Constable's and the landlord's circumstances and the impacts of the cabin – including that Constable was currently in breach of the Building Act and liable for Council Action – Kee found the landlord had not unreasonably withheld consent to the cabin remaining on the premises.
