This is a guest post from Brendon Harre in Christchurch. It addresses an issue that’s near and dear to Transportblog: How do we better enable positive change in the built environment?

Solving the housing crisis in New Zealand will require many reforms and much effort. Some of the needed reforms will face opposition and will be difficult to implement. There will be tension between the national concern about improving housing supply versus some local interests in retaining the status quo.

I want to focus on one particular easy to implement policy option, which I think could successfully navigate this political dynamic. The essence of the proposed reform is to establish a nationwide intensification right for situations where neighbours agree. A right to reciprocal intensification will create a new urbanist tool for New Zealand, allowing a better housing intensification supply response, so that people can build in parts of our towns and cities where people want to live.

The first step would be to agree as a country on a height limit that all property owners could construct up to as a right. I would suggest three stories would be reasonable, as this is a similar scale to natural features like trees.

The ‘Six Sisters’, John Street, Ponsonby

Local areas through zoning provisions would still retain existing setback and shade planes rules that determine how far buildings must be constructed from site boundaries. For instance, a shade plane is an angle going inwards, which building height and bulk cannot exceed. It is taken from a certain height directly above the section boundary -2.5 metres in the below diagram. These rules also limit the size of buildings – and hence reduce the number of dwellings that can be built on a given site.


The second step, which is the main thrust of my proposal, is that New Zealand should adopt a system where neighbours can reciprocally agree to drop the shade plane and set back restrictions along their common border. This reciprocal intensification right could be implemented as a national policy statement under the RMA, which local authorities would then be obligated to implement. So in the above diagrams, if there was a section to the north or south and if the two property owners agree, then they would both have the right to build up to their adjoining boundary – utilising the appropriate building code for firewalls etc. If other adjoining neighbours disagreed, then on those boundaries the standard setback and shade plane rules would apply.

Of course there would be many property owners who wouldn’t want their neighbour to build right up to their boundary. But some would see the advantage in co-operating, so they have the option of adding a granny flat or redeveloping their entire site. Making this reciprocal intensification right a choice eliminates the major criticism of up-zoning. Being, up-zoning dictates an exchange of a neighbour’s access to sun, views and privacy for the opportunity to intensify. Some property owners believe they will be worse off if this exchange is codified into the zoning map.

If reciprocal intensification rights were spread across a large enough area, then this would give the opportunity for a lot of intensification – in the form of duplexes if two neighbours agree and European style terrace housing if many neighbours agree. There are 1.8M private dwellings in New Zealand – if just 1% of those properties were intensified from one dwelling to three per site over, say, ten years, that would net an additional 36,000 new homes. I am not sure if 1% and one house intensifying into three are reasonable expectations, but it shows that even with modest assumptions this proposed policy reform could have an impact on the housing market.

The main benefits of a right to reciprocal intensification are:

  • It decreases transaction costs for site assembly. The national policy statement would mean no resource consent or property purchase would be required to develop sites more comprehensively. Currently to achieve site assembly, either neighbours would have to go through a complex and uncertain RMA process or a property developer would need to buy up the neighbouring sections.
  • It encourages a more desirable urban form as it gives property owners the ability to build across their property frontage so that new housing faces the street. Currently our zoning rules encourage infill housing that goes down the length of the property.
  • It gives greater housing supply options for building types with construction costs per square metre comparable to standalone housing.  Small apartment buildings tend to be cheaper to build compared to high rise apartments because they can be built as 3-story walk-up units. There is no need for an expensive concrete elevator core, mechanical ventilation, sprinkler systems, underground parking and expensive structural engineering.
  • It allows housing supply to respond to locational demand.
  • It allows housing supply to respond to housing size demand.  There is evidence of an under supply of 1–2 bedroom homes in the property market: The largest increase in household groups are singles and couples, yet very few one or two bedroom homes are being built.


I believe reciprocal intensification will be driven by both supply – in terms of its ability to lower the cost of infill and redevelopment – and demand. Demand will come from urban areas with high amenities – like proximity to employment, easy public and private transport access, markets/shops, entertainment and desirable natural environments like beaches, parks and forest.

In Auckland not all high amenity areas have been up-zoned by the new Unitary Plan. So for the city most suffering from New Zealand’s housing crisis there is an opportunity for reciprocal property right supply to increase housing supply in places where there is a demand for it. Density maps of Auckland indicate that outside of the city centre there is a sudden drop-off to a flat density gradient, unlike similar sized and geographically constrained cities –such as Stockholm. Economic theory indicates density should gradually decline with what is labelled the ‘missing middle’ housing.

Missing Middle

Reciprocal intensification rights will not by itself be enough to enable all of the development we need. Other intensification restrictions such as minimum section sizes, minimum car parking requirements, site coverage rules, viewing shaft restrictions, heritage restrictions, secondary kitchens, etc may be as or more significant in the way they restrict the supply of housing intensification options and should also be reviewed by affordable housing policy makers.

However, I think reciprocal intensification rights would be a less controversial first step to intensification compared to widespread up-zoning, which results in some property owners who oppose intensification to fight such measures. These local interest groups which may only represent a minority of locals obstruct reasonable efforts to address restrictions on housing supply.

I believe New Zealand should give greater weighting to the national concern about affordable housing supply compared to the minority local interest in retaining the status quo. It has been my goal with this reciprocal intensification proposal to create a fair and appropriate first step to address this imbalance.


  1. This article was based on an article for titled Brendon Harre and David Lupton set out the case for more, and more variety of intensive housing options in New Zealand’s urban areas and a longer version of the article which also discussed the possibility of larger co-operative neighbourhood schemes.
  2. There are some architectural slides from a US city that transformed traditional standalone housing suburbs into suburbs of duplexes and terraces by reducing allowable section sizes to a little over 100sqm and by not having side yard setback and shade plane restrictions. The end result is quite pleasing.
  3. There is an article and podcast of an academic economic discussion of the wider costs to the economy that unaffordable housing imposes, how the various restrictions on house building contribute to this and some possible remedies, H/T Facebook group Market Urbanism.
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  1. Yes- I completely agree and have long thought this. Residents next door to a new Bunnings Warehouse (for example) should definitely have automatic right of infringement to the same degree. Not just on HIRB but on lots of rules.

    HIRB infringements usually only require the affected neighbour’s signoff – they’re not typically publicly notified consents. It’s fairly easy therefore to say to your neighbour “I’ll sign off your HIRB if you sign off mine” If you’re a developer who owns two adjacent sites, the you don’t even need a consent to do a duplex (as long as you comply with other rules like daylight admission).

    HIRB and some other rules like Max Building Coverage are not actually effects-based and are just hangovers from the old Town an Country Planning days when Planners needed very simple diagrams to be able to assess something. Now we have digital tools like sunlight analysis modelling. Privacy & outlook can be assessed more accurately in 3 dimensions. HIRB is just a blunt instrument that misses the point and leads often leads to pretty dreary urban outcomes.

  2. There’s another obvious thing we can implement, something you can spot easily (or not easily, depending on how you look at it) in Europe: allowing to build walk-up apartments instead of a big house. Especially given the discrepancy between house sizes and actual household sizes.

    You can spot them in European cities, but only if you look carefully: on the outside, those low-rise apartments usually looks exactly the same as a house. You have to go up close to spot things like multiple letterboxes and multiple doorbells. And why would they look dramatically different? A 150m² house and a walk-up with 3 50m² apartments are going to have a similar total floorspace.

    And given that flatting is pretty much the only option outside the CBD for singles and couples without kids, the occupancy and number of cars are not going to be that different either.

  3. This would be a great start in the better utilisation of urban and suburban space. There are many benefits of doing away with sideyards for example in the quest for light and privacy that many of the rules in District Plans do not acknowledge. Reciprocal intensification rights is perhaps not the best answer, but it would be a dam good start and a worthwhile experiment. The overriding caveat of course is that it must be good design because poorly designed high density areas could easily become poor quality areas that could progressively degrade through diminishing desirability.

  4. Under the current unitary plan, setback and shading can be waived if the neighbor agrees, or if the sections are owned by the same owner.

    However most neighbors who do not have plan to redevelop will decline.

      1. Clearly you would add a covenant to the title, same as you have with a right of way, party wall, a drainage easement or various other things that are binding across adjacent properties. For example my neighbour has the right to drain his sewer across my property, a deal made by the previous owners when they subdivided, but still binding on us current owners who had no say in the matter.

        If you agree on the terms they go on the title, if you subsequently change your mind you can try and renegotiate, or deal with it.

  5. I think a “Cast the first stone” rule could work well. If a neighbour already infringes a rule and has existing use rights then they shouldn’t be allowed to object to their neighbours proposal to infringe the same rule. How many times do we see people who live in a building that doesn’t comply try and stop their neighbour from doing the same thing? “I have no parking and use the on-street parking so you need to provide your own” . Or “I live in a building built right to the boundary so you need to keep your side yard”.

  6. Do Transportblog readers think as knowledge of reciprocal intensification property rights became more known this would assist in a cultural change allowing neighbours and neighbourhoods to gradually become more accepting of intensifcation?

    1. The cultural aspect intrigues me. The rules, and a lot of the arguments against “intensification” reflect a strong aversion to the idea of having neighbours. People don’t want to see their neighbour’s house. They don’t want to hear about it. Living in Auckland, population: 4 (or whatever your household size is).

      In contrast, it appears developers have no trouble selling apartments and town houses. And due to having all those huge houses for tiny households, a lot of people are flatting all over the place. And lots of people just can’t afford anything which complies to all those rules above.

      So there’s definitely different attitudes out there. One of them clearly has more political influence than the others.

    2. Hi Brendon,
      I think that is the best question so-far in this thread. Laws, local-body regulations and basic property ownership rights can only do so much. The intransigent and myopic nature of so many people (perhaps because they are not invited to the neighbor’s barbecues) is the real issue here. HOW on earth do we alter that energy into something dynamic and positive?

    3. Depends on who is talking about it, if it’s just TransportBlog readers, it might take a while to a wide enough audience. If the professional bodies involved with planning and building promoted it, there might be a quicker uptake.

      WIIFM and general self interest will probably guide the uptake rate.

    4. Agreed Nik. I have no stake in the property mangling community myself (not a home owner – boarding 16 years same place). I simply observe as a non-participant in the real-estate “interested parties sector” that most of the influential movers and shakers quickly adopt pork-barrel politics as the method of compromise to obtain the desired outcome. And who am I (as above) to question that?

        1. Yes 🙂 They had little decks and windows on the carpark side that didn’t work anymore. I guess that is what happens when you buy in a business zone and expect residential amenity.

  7. I don’t see this as nearly enough and as someone else said you can do it now if both neighbours agree. But what I think is really needed is that we allow two story building up to side boundaries almost everywhere.
    This doesn’t come easy for me as a solar architect for 30 years, but we need to get past expecting to be heated by sun coming over the neighbours property. The Passiv Haus people and the superinsulated house people in Canada before them have shown how to do this is radically colder climates than Auckland. We need to say yes to utilising the waste 1m of land between houses and boundaries and yes to having party walls on boundaries that have zero heat loss though them. We need more terrace houses for compact urban environments. Putting more houses on each piece of land, is I think one of the keys to lowering house prices as it doesn’t cost much more to build a house in Auckland than in Ekatahuna – its just the land cost that makes it so expensive in Auckland. Secondly those other 2 or 3 houses that could have been built on that plot of land, are now way out of town, in sprawling suburbs. If those 2 or 3 other houses could have been built on the site, it would mean a greater viability for a corner pub, a more frequent bus service and better corner dairy.
    Just to reiterate: party walls are effectively super insulated without even trying as there is zero heat loss (if you assume same temperature each side of wall). Almost all sites will still get some sun at some time of the day from the front and back, even if they get none across their side boundaries.
    And with zero heat loss out the sides of our (terrace) houses, its much easier to get to zero external heating of a house, even without good winter sun.

  8. By coincidence yesterday I was looking at what I can do under the proposed Unitary Plan with my 2 bedroom B&T house on a 900 sqm back section one of Auckland’s leafier suburbs. Not much it turns out, even though it’s now in a Mixed Housing Suburban zone. I can build four dwellings but I can only go up two stories, so I’m looking at 4x 2 bedroom units (thank you HIRB!! ) – 2 upstairs, 2 downstairs.

    The problem is that even for a leafy suburb I can only get $1.5m (average) for each unit and since the CV is $3m do I really believe I can build 4 new units for less than $2m so that I can make a profit? Not in this construction boom.

    I’ve been holding on to the rental (bought it a few years ago to build our dream home but it all got too expensive) to see how the UP went, but clearly the Mixed Housing Suburban zone does nothing for me. Hopefully that is not the case across the city, otherwise our housing problem won’t change.

    The problem IMO is the HIRB. If I could build 3 x 3 storey townhouses (similar to the ‘6 Sisters’ above, to keep in character with the neighbourhood) I would – but I can’t because it might ‘tower over’ a neighbour. And anyone who suggests I ‘should have a talk with my neighbours’ probably hasn’t lived in a leafy suburb. Getting anything non complying signed off by a neighbour is like flying a unicorn to Waiheke – not gonna happen. Unless they need something in return.

    1. So you can’t make a capital gain killing on your property building something your neighbourhood doesn’t want. Boohoo. Sounds like the system works then (until someone overrides democracy in action like this, because it doesn’t suit the Government).

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