The concept of Skyways

In a recent comment Mike said, “Daniel has obviously never been to Minneapolis Minnesota in the USA. They solved the weather, connectivity and transportation problems by interconnecting all of the CBD 1st floors…warm in the winter, cool in the summer and smooth consumer flow from store to store and block to block.”

The term Skyway was not one I have really thought of when visualizing our interconnected buildings ideas so I did a bit more digging.

A quick bit of googling I came up with a lot of info:
The all-knowing Wikipedia has specific info about the Minneapolis Skyway network, and more info about Skyways in general.

In Minneapolis the skyways are all enclosed, from what I can see, and are owned by the buildings they connect to, with some having different opening/closing hours, depending on the businesses the access. Which definitely makes perfect sense in an environment where it is hot and humid in the summer and below zero for for the winter.

We had/have at least 3 skyways in the CBD pre-quake (two into the food court in the bus exchange, and one from the town hall and the convention centre) and there is one I can think of at the Westfield mall.

In our climate it’s not so critical that they are enclosed though, and I can see that if a building had an open rooftop component then the skyway could connect to the building with a landing type of area, which gives access to the inside of the building (during opening hours) and also the rooftop section (24 hours) to continue the flow of the pathway.

Skyways are very, very common though. The  general skyways entry lists skyways in many cities across North America, Europe and Asia. In densely populated places like Mumbai, Skyways are being developed as a way to manage pedestrain flow in an environment where there is just too much activity going on at street level. Obviously that’s not an issue in little old Chch but it is another angle to consider.

An excellent addition to the discussion, thanks Mike!

If you have any other info on this concept, please post in a comment.

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Example of elevated garden city concept for a block

This is an example of how the elevated garden city could look for an entire block in the city.

The key things that are a little different and more practical than initial concepts are:

  • The elevated garden is only one floor high and most of the buildings look out over the garden open space.
  • All foot and cycle traffic is on the elevated garden level only
  • There is no need for multi story car parking as ground level with no foot traffic is car park/delivery truck pick-up/drop-off (much cheaper given the number of car parks)
  • Using more area in the city to build on (no need for car parks on side of road or foot path so buildings can have larger area – more urban density)
  • Better flow of cars – no pedestrians, bikes, multi floor car parks to go up and down
  • Better flow for pedestrians and cycles – no motor vehicles to get in the way – much faster to wander around town
  • Greener – easier for bikes, less energy for cars (no up and down buildings)
  • Easier for people to come into town – instead of one park outside a shop there could be 12-20 directly under a store. It doesn’t have to be a grey car parking building but could have advertising/window displays to draw people up to the shop/restaurants etc
  • Much better use of space as no need for delivery alleys etc that can take large chunks of land
  • All building services (air conditioners, wiring, piping etc can be on the ceiling of the car park) – easy access for maintenance etc
  • For the same number of car parks/rentable space it could be about the same price as conventional block design.
  • Much more iconic than a normal city block!
  • Lots of creative ways designers could go with the general idea to link up different blocks with variation on the theme
Posted in Discussion | 2 Comments

Summary of the idea and resulting comments


I’m really impressed by the quantity of discussion this website has generated. Hundreds of comments added by both convinced and unconvinced people show that people want to be involved in the city’s future even if they don’t agree what it should look like.

Rather than wading through the hundreds of comments I’ve tried to summarise what people have said so far in order to make the discussion more accessible. This is one of eight summaries covering various topics, including inspiration, vision and environmental considerations.

Personally I’d like to see this discussion moved into something like a wiki or drupal to make it easier to read and get the value from people’s opinions rather than them becoming lost in a seemingly endless stream of ideas. However, it’s not my content.

This summary was current as of 3:30pm, 19 March 2011.

– Patrick.

The Idea

The fundamental aspect of the project is to create a unique city center unlike anything else in the world that is functional and remarkable in its design for both inhabitants and visitors. It is hoped that it could be a relatively low cost way to create an iconic world destination for tourists and creative people.

Street Level

Existing street level could remain the primary circulation route with nice wide avenues providing access to large below ground carparking lots, bus, tram and rail stations. Public vehicular access could be limited to this level, which would also be shared with the most utilitarian users who have no need for either sun or views.

First Floor

The next level up could be occupied by those public users who require foot traffic, but again are not totally dependent on sun or views, such as you would find in a traditional mall, or large office spaces, sun could be brought into this level through clever use of roof lights, voids, etc.

Second Floor

Roof gardens above to create a park like atmosphere amongst which would be located the cafes, boutiques, hotels and apartments. This way rather than a series of interconnected roofspaces, and all its inherent difficulties you would end up with a layered cityscape resembling something more akin to a rolling hillside (on a conceptual level of course), with voids and pathways, pockets and promenades amongst which to enjoy the city.

Vehicular access to higher levels could be provided by either ramps or vehicle lifts to permitted vehicles during resticted hours to allow stocking of stores, etc, or alternatively central distribution points be located throughout the city to allow delivery of goods to and from stores. This layout could also facilitate a state of the art light transit system to deliver people around the city once they have parked their car (if they actually now need a car to go about their day to day business)

CBD Edges

The fringes of this development adjacent to the river, etc would cascade down to the ground level providing 2 – 3 levels of prime positioning around the perimeter. Thus it would be possible to blend the city in with Hagley Park rather than having a single jump to to a 2-3 story high level that will shade the lower street.

Not all buildings must match this

Putting some buildings higher than the grassed areas can provide those areas with shelter or glass could be used to create shelter.



Could you walk barefoot around the CBD on grass without your feet ever touching the ground? By linking all the buildings together at the second floor level using bridges you create an entirely new public space. A network of covered walk-cycleways connect the various roof-tops together and slope down to other public spaces at ground level. This would alleviate some of the constaints put onto pathways by the grid pattern dictated by motor vehicles. Pathways could wind through the city like the Avon River, with lots of trees like Portland, Oregon. These bridges could be standardised in how they interface with each other and wouldn’t necessarily have to be made from concrete. Beautifully designed wooden bridges can easily handle foot and bike traffic. The system could be biased to be best for bike traffic to get around easiest. Amsterdam includes masses of right of way cycle tracks so that is it super easy and safe to get around without having to compete with cars. There could be places to store bikes at the elevated level and these could incorporate hire systems for bikes, motor scooters and segways. Lifts and escalators may be required for the less able to move between ground level and the elevated gardens. There are outdoor moving staircases in Barcelona but I think that their climate is drier than Christchurch and of course there will be energy costs for them. Although potentially they could be solar powered from the remaining roofs.

Some buildings would prefer to not have bridges to their buildings where they are trying to keep access to their employees only. Here they could put up a fence but they’d still need to provide a walk-way to connect to other buildings.

Faster transport could be provided by elevated monorails or free buses within the city or by extending the tram network.

There is the concern that removing foot traffic from the ground level destroys that retail environment and creates a people fee traffic dominated environment. Can you create an urban park above but retain the street as a multi-purpose environment?

The Green Stuff

An elevated garden that stretched across the flat roofs of a city would require significant organisation. How do you get all the soil up there if you can’t drive trucks on top of the buildings? Do you not even try and let the soil mature and develop over time? If the city’s roofs are covered in grass does that mean the CBD would hum with the sound of lawnmowers constantly? Or do you leave sheep to graze the grass for you? The tourist shops might be quite keen on that idea! What sorts of plants to you use? Bamboo species because they are lightweight and respond well to being contained and can create some privacy or native bush to encourage our native species? Do you grow different biomes on different rooftops and add community gardens and bird sanctuaries to others? Growing trees on top of buildings may be quite difficult but could you grow them beside buildings and wait for their branches to grow over the top in years to come? Or grow trees on earth ramps that lead up the sides of buildings as entranceways to elevated levels? Would planters be better and easier? Perhaps you could even return parts of the city to its natural swampy state? And amongst all this damp wet earth, can we keep the buildings underneath dry and warm?

Wind and Sun

Gardens are great on warm evenings but what about our cold rains and winds? Lots of wet grass, dirt and leaves may not be practical in the city center. In the summer, who wants to be on a roof in a north-westerly wind? You need shelter and shade in the summer and somewhere warm in the winter months.


Kids climbing on low fences along walking bridges is a worrying consideration. Plants could be used as walls or to hide fences so that people don’t fall off and also don’t have to look at fences all the time. Flower beds could be put in as obstacles between people and the edges of the roof.


Green roofs reduce storm water run-off by providing a buffer in the soil layer on the roof that holds the moisture and releases it more slowly. However, flat roofs and snow can be a dangerous combination if the roof is not designed for unexpectedly large snow-fall events!

Water that is collected would still have to be connected to spouting systems to avoid it building up over time. However this water might also be stored and then reused for irrigating the green areas, purified for drinking or collected into water features such as beautiful streams or waterfalls which may have added benefits for cooling the environment in summer.


How do you not make the ground level an overshadowed ghetto of rushing traffic and dark unattractive spaces? Is it possible to make both attractive to be in, although they may be different from each other? Can buildings be designed so that natural light penetrates through them to the bottom floors? If you have the option of leasing a building with a bright restaurant on top and two floors of dark offices below in the city vs one outside of the city with two floors of bright offices above and more dim ground floor, which would you prefer to spend your working hours in? Solar collectors or just plain good design may overcome these issues.

The Urban Heat Effect

Cities are hotter places than parks. The grass and trees in parks absorbs the sunlight and uses it’s energy in photosynthesis to create sugars. The result is that they output lower quality heat which we recognise when we move from the hot tarmac to the cooler grass. While both have been experiencing the same amount of sun light hitting them, the grass is cooler in summer to stand on and the air temperature also reflects this. Bringing more greenery into the CBD can cool it in the summer months, making it more pleasant to inhabit.

Doing it anyway

The thing that scares one person the most right now is the feeling of being “enclosed” and “surrounded” by buildings. A green space covering the CBD would remove this fear and provide an amazing space to show the world.


Posted in Discussion | 5 Comments

So what next? How can you help?

Firstly – what a clever lot you all are….fantastic set of ideas and discussion that is very cool to see it evolving in interesting directions. It feels like you have taken ownership of this already which is exactly what we hoped might happen .

There are two key things you can do to help accelerate this idea. First is to continue letting as many people know about this as possible – the more smart people that start thinking about these things the better.

The second is to start adding more detailed flesh to the ideas. These models on this site were thrown together in a few days and we really need some folks skilled at modelling/sketching to bring some of the ideas mentioned alive so others can see the possibilities.

The fact that so many people get excited and all we had were relatively boring grey rectangles linked together is kind of encouraging. We would love to see people create more detailed images of:

  • How linked retails precinct could work on the elevated garden link – tied in with covered walk ways?
  • More creative office/hotel/residential buildings and precincts with the elevated garden integrated
  • Some more curves and split levels
  • Ways generic building elevators/stairs could be created to be used for both buildings and public (opportunity for retail shops to increase flow through past shop windows?)
  • Innovative public spaces – e.g. maybe the slopes up to elevated garden could sweep around half of the square making the cathedral the centre piece. This could form a natural amphitheatre that could be used for concerts possibly including an innovative retractable roof? – hey we may be allowed at least one or two expensive things as well….
  • Ways to link in heritage buildings both rebuilt and possibly some left as ruins as a reminder. Imagine half the provincial chambers returned to former glory and half left in crumbles state to view safely from above (unique EQ generated sculpture?) – possibly more interesting than it was before? (and probably cheaper than a full rebuild)
  • Some of the crazy things like having sheep. I assumed someone was having a laugh but if you sold ugg boots and sheep skins to tourists a few outside may not actually be silly
  • Some detail on how the bridges/fences could be designed together
  • Water features that could look like streams with modern twists for effect
  • How the elevated walk/cycle ways could be created to best effect – main flows covered?
  • So many other things too…….

We are hoping architects and designers will get creative with this and it could get quite interesting. If you have anything you would like to contribute let us know and we will post them up.

Posted in Discussion | 4 Comments

My thoughts on the Elevated Garden City idea

Grant shared the Elevated Garden City with me over the phone last week. It immediately sounded pretty cool.

In my past professional life I graduated from Canterbury Uni with an hons degree in Geography, and then spent the first 8 years of my working life making maps with fancy GIS software which cost $100k and required arcane knowledge of cryptic commands and codes to achieve what my mother can now achieve in 3 clicks on Google Maps.

Even though I have since been distracted by the Internet, and spent most of the last 12 years building virtual spaces on the Internet, I still have a passion for real spatial and visual information, and Christchurch is my home town, so I was happy to get involved.

We agreed to build a website to try to communicate the idea more clearly and also to give us a place where the idea could be discussed and expanded on. Grant registered the domain, and I set up the site.  At this stage my thoughts are very similar to Grant’s but they are probably worth sharing.

My vision of the Elevated Garden City (at the moment at least!) is:

  • Replace demolished buildings with 2 or 3 story buildings that have office space on the lower floors and retail space on the top level.
  • Connect the buildings at the upper levels (above road level at least) with walkways so that people can move between buildings easily without having to descend, which leaves the traffic flow below unimpeded by pedestrians and vice versa.
  • The buildings would have flat roofs that could be developed into or incorporate “elevated garden” spaces. These green spaces could be incorporated into upper level (or even down into the lower level to create a courtyard or similar) or could just be a retreat at the top level (eg: BBQ/Picnic area).
  • I also could see that the flat roofs and/or other surrounding roofs could be used for solar and water collection to feed the buildings below.
  • In addition solar light collectors could be installed on the roofs to provide sunlight into the office spaces below.

My immediate thoughts where of some of architect Bjarke Ingels ideas that I saw in his TED talk from 2009. (Bjarke Ingels is principal of BIG, based in Copenhagen.)

Particularly the bit about the “Mountain Dwellings” development (as featured on the still from the video above).

As terrible as the devastation has been in Christchurch it excites me to be thinking about the future and how we can rebuild out beloved city.

I look forward to hearing other peoples thoughts.

Posted in Discussion | 8 Comments

Christchurch’s Elevated Garden City

The opportunity

The 2010-11 Canterbury earthquakes are an opportunity to create something special in Christchurch.

Imagine a garden city where we took the Manhattan rooftop garden to whole new level.

Given that most people in the CBD will not want to live and work in high rises, then this new set of low rise buildings give Christchurch the opportunity to build an elevated garden/walkway space that could become one of the world’s iconic cities.

Instead of the roofs being wasted space it would be possible to make the space useful and linked with walk/cycle ways. You could walk bare foot around the CBD on grass without your feet ever touching the ground. Visitors landing in our fair city would look down on roofs of pure green. With new sustainable, energy-conscious buildings we would become the greenest city in New Zealand inside and outside.

The roof space could be used for:

  • Parks
  • Cafes/Bars
  • Shop fronts
  • Office entrances
  • Playgrounds
  • Court yards
  • Sports areas
  • Iconic wooden bridge designs
  • Slopes from other public spaces could go up the elevated gardens
  • Not all space has to be public could be office BBQareas etc
  • Taller buildings that look out over the gardens
  • Bird sanctuary – (no rats or cats)
  • Native forest – Riccarton park (maybe turn Latimer square into this?)
  • Bike hire scheme
  • Lots of other creative things

How it will work from a planning point of view

  • Every new building has to have half (or 1/3 or 2/3) of the second or third floor dedicated as open space
  • The council will create a network of linked walk/cycleways connecting the second or third floor roof spaces
  • This will be a relatively simple set of rules that would allow building owners/architects lots of flexibility and creative options.
  • Could start small in the centre initially but could grow long term to take in all 4 avenues.


  • Relatively low cost way to create a city that could become an iconic world destinations for tourists and creative people
  • Every building has an extra elevated street frontage
  • Ability to do something a bit different with each property depending on if it is housing, office, cafe, retail etc – creative options for all buildings.
  • There will be vastly more useful space in CBD not just dead roof space!
  • Can still use relatively inexpensive building techniques but create something dramatically different and unique when linked together
  • Easy to get started and can expand over time
  • People will be able to walk and bike around without cars in an easy, safe way – will probably be the preferred way to get around town on short journeys
  • Building interfaces will be standardized sothe bridges can be relatively inexpensive – only foot and bike traffic
  • Still has possibility for good urban density – backyard on roof as the concept expands to the out skirts of four avenues
  • Very simple set of planning rules that still allows lots of room for creativity but ties the city together in a distinctive iconic way

Elevated Garden City concept image

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Elevated Garden City concept image

Posted in The idea | 10 Comments