With a housing supply shortage putting pressure on Kiwi, the government recently announced it’s planning to relax the rules around granny flats.

It’s proposing that those dwellings can be built in rural and residential zones without a building or resource consent, as long as they meet certain criteria, aimed at reducing the risk of structural failure, fire and its spread, weathertightness failure and insanitary conditions.

It would also require the dwelling to be built by "trusted workers", to a "simple straightforward design", and be notified to councils.

Architecture and planning expert and University of Auckland lecturer Bill McKay says the move is welcome news for many.

“I know a lot of young people who are interested in tiny houses, but also a lot of families too.”

But that doesn’t mean you can buy a patch of land and build one in isolation.

“It's got to be ancillary to the main house, and has to be part of that property. So it's very much directed at someone who already owns the house and wants to be able to build something for a granny or a younger family member.”

Currently some councils already allow granny flats without resource consent, but there’s a lack of consistency and different standards across the country.

“Don’t confuse granny flats with the existing ability to put up a shed or cabin without building consent too. The size for that used to be 10m2, but the last government increased that to 30m2.”

“But a cabin is for work, recreation or as a sleepout. You aren’t allowed plumbing so no kitchen, toilet and bathroom. Liberalised granny flat rules, will allow kitchens and bathrooms.”

WHAT CAN YOU BUILD?

According to Stats NZ, the median floor size of a new home consented in 2022 was 126sqm - and under the proposal, the dwelling could be just under half of that up to 60m2.

There’s nothing that puts a limit on the number of bedrooms too.

“Imagine something 6x9m or 7x8m. That’s a pretty decent size, so I reckon you could do two bedrooms as well as a kitchen and living area. It could almost be on the scale of what you’d see in a retirement home.”

It needs to be one storey, and separate from the main house - not an addition.

McKay says this also doesn’t mean it’s ok to DIY, but it does open up a whole raft of possibilities around the construction of cost-effective kitset homes.

“They could be retrofitted with a bit of plumbing. I can definitely see a whole bunch of people jumping into the market as a result, because there are more prefab businesses out there gearing up.”

WHAT CRITERIA IS THERE?

There may not be any consents required, but there’s still a list of criteria the dwelling needs to adhere to.

Firstly you need to notify your local council that you’re planning on building a granny flat and get information off them about drains and floodplains. You then need to notify completion and provide them with some information.

“That will involve them producing a form that you fill out. I imagine they’ll also want a few drawings showing where it connects to the water supply, and where the plumbing and drainage goes.”

“I think they will probably ask, who built it? Or if it was a kitset home, where did that come from? So I think we'll see a bit of compliance stuff.”

All dwellings would still need to comply with the Building Code too.

“A licensed building practitioner must build or supervise it or use pre-approved kitsets.”

Your plumbing and drainage must also be connected to council infrastructure. If that’s unavailable, then on-site treatment systems will need building consent.

HOW WILL THE CRITERIA BE ENFORCED?

Mckay says much like current compliance policy, he suspects there could be random spot checks similar to swimming pool fencing.

“Councils look at aerial photos and knock on your door and all of that, and check periodically on swimming pool fences.”

“I think there could be a little flying squad of council people who end up just doing odd checks on granny flats.”

McKay says compliance also isn’t only about keeping councils happy, it’s about making sure everything is legitimately built especially when the time comes to sell your property.

“I've noticed this especially with giving code compliance certificates and things like that. More and more builders and architects get it done upfront now, because otherwise the phone rings four years later when people sell their house and it’s a big mess.”

WHAT TO LOOK OUT FOR?

McKay says the proposal is "not as simple as we think", and a lot will still need to go into the planning stage so you don’t get caught out.

“One of the areas in the proposal that’s a little bit vague is around resource consent and planning rules, and there’s a lot of little rules that even some architects aren’t fully aware of.”

“A classic trip up can come from people thinking they don’t need building consent, but still end up needing resource consent. That happens all the time with all sorts of things.”

McKay says one of those scenarios is if the dwelling is in close proximity to the boundary which then poses a fire hazard for the neighbours.

“I'm really looking forward to seeing what feedback comes back on that and reading the finalised version of the proposed changes.”

The proposal suggests introducing a ‘National Environment Standard’, which will be a set of permitted activity standards around size in relation to available space, proximity to boundaries and permeable ground.

The changes must be balanced against existing issues, including managing flood risks, and certain district plan rules will still need to apply. 

“If you can’t comply, you’ll need to apply to council for consent as usual.”

WHO CAN OWN IT, AND CAN I RENT IT OUT?

McKay said there needed to be common ownership with the main house. The area could be subdivided and then sold, but there would be "hoops" to jump through with doing that.

It was also up to existing council policy for whether or not it could be rented or used as an Air BnB.

McKay says the proposal is a great start, but it is just that - a proposal, and the rules haven’t kicked in just yet.

The Ministry of Business, Innovation and Employment is now seeking feedback on the options around changes to granny flat rules, with submissions due by August 12th 2024 and changes due to come into effect next year.

For more information visit https://www.mbie.govt.nz/have-your-say/grannyflats