Today's instalment of The (Ideas) Zone presents a range of solutions and expert views. Those experts and I will be online today to blog with you. Just post your comments and questions at the end of this piece and we'll respond. The (Ideas) Zone is an online space for you – a space for the community to discuss ways to make our city and our state even better places to live and work in, to share and to enjoy. But before we get to that discussion, and I'd love you to join in, let's stay with the floating dwellings. Here's some in Seattle, where real estate company Copper Jacobs specialises in such properties: And here's one in London, called Inachus Floating Home, by Sanitov Studio. It is so well insulated it requires zero heating. It uses natural ventilation to create zero carbon emissions.

It was launched at the London Design Festival as part of the its Future Cities Project. The creators of this home say: "It was named after the Greek river god, 'Inachus'... Waterways of cities may become part of the urban fabric. The model is envisioned on a larger scale, as mass communities of customised houses on water. Influenced by Danish design and detail and executed by British master boat-builders, the smart residence is outfitted with appliances and systems which may be operated by smart phone or tablet." This what it looks like inside: There are many years of experience upon which me might draw in exploring the floating option in our city. Here's a beauty from Copenhagen in the 1960s (pic courtesy of Henrik Moltke/Flickr):

Before we move on from the waterways option, here's a final example, this time from Sweden (pic from La Citta VIta/Flickr). Looks like it could almost be in Docklands... Floating homes are but one of a number of radical - and less confronting - ideas to fix one of Melbourne's biggest problems; a lack of housing options. It's a menacing situation that is already shackling our aging and rapidly growing population's ability to enjoy life in our sprawling metropolis. In essence, we have too many dog-box apartments in the CBD, too many massive new homes on the fringes and too many single dwellings on quarter-acre blocks in the middle suburbs. In recent years, what were supposed to be the city's inviolable boundaries have blown out again and again, as politicians capitulate to pressure from developers and from young families who cannot afford to live close to the centre of the city. It is now 150 kilometres from the eastern boundary to the western one; further than from the CBD to Bendigo. It's not working and will only get worse if we don't make changes. Incidentally, if you doubt we have some big issues to fix, it would be worthwhile having a look at some very recent work by independent research centre Grattan Institute. My colleague Clay Lucas encapsulated its main points.

Here are the other nine ideas: 1. CONVERTED SHIPPING CONTAINERS: Would you live in a home created from shipping containers? It is a lower cost yet design-driven alternative at a time when so many people want to buy a home but can not afford to even enter the market. Here's an example by a firm called Royal Wolf, which has developed a prototype accommodation unit which can be fitted with insulated walls, plumbing, electricity and a staircase. And this is what it looks like inside - that's real estate agent Bob Allan. The three-bedroom home was made from four old shipping containers in Sydney back in 2005, when it was priced at around $140,000. It can be readily moved, and includes two bathrooms, timber floors, air-conditioning, a kitchen, laundry, balcony and sewage treatment tank.

Here's another taste of what you can do with shipping containers. This space was created by Sean Godsell, the fella in the picture, one of Melbourne's most-prominent architects. He calls it "FutureShack" - and conceived it to shelter the world's displaced, including homeless refugees, victims of natural disaster or the survivors of war. Here's an example just out of Geelong, in Leopold, created by Geoff Fulton and Carla Salomon (both in the pic) of Fulton and Salomon Architects, a firm that specialises in using shipping containers to make terrific, affordable homes.

Meanwhile, over in Hebburn, here's Madeline McCristal at her house made from shipping containers. 2. MODULAR SPACES Would you live in a modular home, where elements can be changed and added at will? Here's an example, an "anti-monolith" home in Alphington designed by Andrew Maynard. It uses several small chunks to double the size of the home and create a village feel. It was covered in Dezeen magazine. Here's a taste:

Then there's this - pictures by Armelle Habib of the Prahran East home of Jan Gyrn, who is co-owner of modular housing company Modscape. 3. ADDING NEW HOMES IN OLD BACKYARDS Someone who knows a lot about all this is the editor and co-founder of Green magazine, Tamsin O'Neill, who is one of the people who'll be responding to your questions and comments.

Here are some thoughts she sent me: "There are some encouraging trends that we are noticing in urban areas. I am increasingly being sent projects that have been built on subdivided inner city blocks. Where once a quarter acre block was the norm it is increasingly becoming a luxury as urban density increases. Large backyards that back on to a lane are perfect to subdivide. On these small blocks we are seeing some really creative sustainable design." Here is an example of what Tamsin is talking about. It was designed by Studio Faithfull, and is project where about 200 square metres was taken from the garden of a Seddon property to build this family home. The image comes courtesy of Green Mag: 4. COMMUNITY-BASED APARTMENT BLOCKS - OR URBAN VILLAGES

Tamsin also loves The Commons in Brunswick, an award-winning apartment development by Breathe Architecture where residents share rooftop gardens, solar hot water, electricity generation systems, roof-top laundry, bike parking and communal beehives. Here' some images of The Commons, courtesy of Green magazine: 5. ROOFTOP GARDENS

If you don't need or want a conventional garden, it creates much-needed space. Here's Emilio Fuscaldo of Nest Architects in the rooftop garden of his home built on a block carved from an inner city backyard. The image comes courtesy of Green magazine. Such simplicity is perhaps widely accessible - and needed, as Michael Leunig suggests. Here's Brenton Weisert on his rooftop garden in West Preston:

We can think big with this one. Indeed why aren't many, if not all, the rooftops of our CBD producing food? My colleague Aisha Dow wrote about this as recently as yesterday. Here's Leroy Ledbetter working in the gardens on the rooftop of the City Hall building in Chicago - pic by Sally Ryan, courtesy of The New York Times: 6. DUAL-KEY HOMES Would you support a law that every family-sized home built in Melbourne must be designed to easily become two or more separate dwellings?

One of Melbourne's leading thinkers on planning and urban design is Roz Hansen, an adjunct professor at Deakin University, a former advisor to government, a private consultant and a founder of Future Melbourne Network, a non-partisan organisation of planning experts intent on helping drive policies to improve Melbourne. She'll be joining the blog session, too, so feel free to push her on her views. She believes we could go a long way towards creating much-needed housing options with one simple move. She says every family-sized home built from now on in Melbourne ought to be designed to be readily transformed into separate dwellings. It would create `"invisible density" – houses would be built ready to switch to independent spaces. They are available now. Here's a plan for a so-called `"dual-key" apartment by Fender Katsalidis Architects. In their dual-key designs, the second, lockable bedroom usually has its own bathroom and cooking area. Here's what it can look like inside:

Here's Roz: `"What if all new family-sized dwellings built in the suburbs had to be designed/wired and plumbed to be able to readily convert to two dwellings to help meet our housing needs in the decades ahead? We know our population is ageing and yet our housing stock is not keeping pace with the needs of people as they grow old. Many are not able to afford/find a smaller dwelling in their local area to downsize and wish to remain in the family home for as long as possible. By ensuring that all new builds in the family housing market can be easily adapted to two smaller dwellings it would enable us to stay in the family home (but in a smaller dwelling) and rent or sell the second dwelling as part of value adding on our asset. "This approach would do little if anything to changing the character of the neighbourhood as the dwelling would look the same from the street but enable two households to live on the site. This is about constructing housing which is adaptable to our changing housing needs; it can cater for families who live in the extended family arrangement, it can double the number of houses available to rent or buy, it can even deliver some affordable housing because the costs of adapting the dwelling are largely met at the time of construction of the 'single' dwelling." 7. PREFABRICATED SPACES The dual-key idea seems to make a hell of a lot of sense. It certainly does for the people in this next case study, which combines duel-key with prefabricated. Prefab is an economical, flexible and design-driven alternative to building or renovating. Let's hand over to Jason Fremder, founder and managing director of design studio Harwyn, which specialises in prefabricated structures. Before we look at the dual-key case study, here's a glimpse of a Harwyn home office pod:

To the case study: Jason is talking of a woman in her late 80s who had neither need nor desire to go into an institutionalised aged-care setting. "She is active and busy and can look after herself. Her daughter worries about her and wants to be closer to her mother for many and varying reasons. Clearly the idea of moving into the house with her mother is not necessarily appealing. The mother is lovely; the daughter too. But the daughter, a PhD student in her mid-40s, needs her space just as much as the mother wants hers." Harwyn Pods are prefabricated in the firm's factory and the turn-around time is between six and 12 weeks, depending on how much work the place is dealing with. Here are impressions of the solution Jason and his colleagues have designed:

Back to Tamsin: `"Prefabricated housing models are gathering momentum. Adding prefabricated rooms to existing houses or dropping a complete series of modules onto an empty block or infill site is becoming a viable option for many. And whilst we are seeing interesting projects from architects we are also seeing their savvy clients researching online and pushing sustainability. `"What's most exciting is the subtle shift in status anxiety from wanting the biggest to out-doing the Joneses with smaller, higher quality, more livable homes that are cheaper to run." And speaking of keeping up with the Joneses, here's another wonderful example of prefabricated housing. It's called The New Joneses, and is all about sustainable living. It's the brainchild of Tamara DiMattina, who I wrote about when she launched the initiative a few years ago and who will also be joining the blog session, the online chat, to respond to your ideas and questions and comments. Here's what she and her colleagues set up in City Square only a few weeks ago, The Carbon Positive House, designed by Archiblox:

8. TINY (AND EXTREMELY CUTE) PORTABLE HOMES A Melbourne-made international documentary premieres in Brunswick this month. It is called Small is Beautiful is a documentary on the tiny house movement - which started after Hurricane Katrina wiped out so many homes in New Orleans in 2005 and which refers to complete homes of less than 9.3 square metres. Here's one made by Australian James Galletly, also known as The Upcyclist: The average cost of building a tiny house is $30,000. At screenings at Monster & Bear on March 26-29, there will be a tiny house built by Fred Schultz on display.

Here's a taste of director Jeremy Beasley's doco: While we're at it, check out this hybrid between a shipping container and the tiny portable home. The 'Dwell' is an extraordinary piece of design and engineering pointed out to me by Roz. It's created by a bunch called G-Pod, who have this to say about it: 'Dwell' is an architecturally designed, relocatable home with a focus on environmental sustainability and impeccable build quality. Dwell is easy to set-up, efficient and affordable. The G-pod Dwell expands into an area nearly three times its original size and can operate off-grid and without mains water." It is designed to be used in various ways - a home, holiday home, office, additional room/bedroom, or just a space in which to relax and unwind. 9. DUAL PUBLIC/PRIVATE DEVELOPMENTS

There is a public housing waiting list of about 40,000 people in Victoria. And about 35,000 people in our community are homeless - they do not a safe place to live and so are on the streets, or sleeping at a friend's place or are in hostels and other forms of temporary and emergency accommodation. We need to fix this, too. One way is to have mixed developments - where public and private housing are built in the same space. Here's a beauty - The Nicholson, built in 2011 in East Coburg. It was a $56-million project developed by the state government's developer, Places Victoria, and designed by architect Design INC Apartments: 199 Completed: November 2011 The Nicholson is a $56 million. It has 199 apartments - 110 are privately owned, 58 are social housing and the remaining 31 affordable rental apartments. It also has eight mixed-use commercial spaces. By the way, it is the largest building in Victoria to use modular construction, with apartments built offsite and craned into position. Here's what it looks like:

10. REPURPOSING EXISTING BUILDINGS Converting warehouses has long been embraced as an enchanting way to create housing options. Here's a terrific twist on that notion - turning a silo into apartments. This one is in Abbotsford, where a grain storage space was turned into 48 apartments, called The Islington Silos, designed by Map Architecture and Design: By failing to create options, we are not only depriving individuals and families of lifestyle flexibility. We are also imposing traffic hell on so many people, at huge social and economic cost. Many, many thousands of people are losing so much precious time and money and suffer so much stress doing this:

So, surely we can do better. Surely it's not beyond us to create more options. Do you have a housing problem? Can you see one looming for you or your family? Do any of these ideas/solutions work for you? Perhaps you disagree there's a problem? Perhaps you have other ideas? Perhaps you have experience to share? Tamsin, Roz and Tamara - shown here from left to right - and I will happily engage with you. Let's have a conversation that might help our lawmakers and bureaucrats realise we need far more flexibility. OK, over to you. Please feel encouraged to post your comments and questions below.