Building affordable homes on water

Governments across the globe are grappling with the question of how to provide affordable housing for their ever-expanding populations. In the Netherlands many believe the solution lies not on land but on water.

Cruise by any of the canals in the Dutch capital and you'll catch a glimpse of people sipping cappuccinos on their floating verandas. Amsterdam, like many Dutch cities, is criss-crossed by an impressive network of canals.

Approximately one-third of the Netherlands lies below sea level. The Dutch have spent decades developing ways to incorporate this excess water into their style of living. It began with the simple houseboat and has since evolved into entire floating communities.

Ijburg lies 8km (five miles) east of Amsterdam city centre. Like much of the Netherlands, Ijburg is a polder, the name given to land that's been "reclaimed" from the sea.

There are roads, playgrounds, offices and shopping centres. To the untrained eye it is difficult to tell the difference between this artificially created island and the land that naturally exists above sea level.

What makes Ijburg unique is that it is home to the largest floating community in western Europe. Situated on a lake, this area represents the relatively affordable expansion of Amsterdam. The houses are built on concrete tanks floating beneath the surface.

They work on the Archimedes Principle: the amount of water you push away underneath determines the weight you can place on top. Just like a ship.

In recent years the Dutch philosophy has shifted from fighting the water to living with it, or rather, on it. Instead of trying to claw back more land from the sea, developers are exploring the cost-efficiency of building homes that rise and fall with the tides.

"We are 10 minutes away from the centre of Amsterdam where you buy an apartment for half a million, or even a million, euros," explains Ton van Namen, one of the developers behind this project.

"These floating homes also cost half a million but then but then you have 160 square metres, which in comparison with your small apartment in the city of Amsterdam, is very affordable."

The list price for these floating homes starts at 390,000 euros ($485,000: £310,000). In overcrowded cities where rent is high and the availability of affordable housing is low, Ton van Namen says it's logical to seek solutions at sea.

"In Amsterdam it's dense, there is hardly any space, so when you want to build a new building you have to acquire very expensive land. Here the water is more or less for free."

Affordable homes is a hot topic in the Netherlands at the moment, with something of a scandal swirling around the subject.

The country's largest social housing corporation Vestia was investing in derivative bets, but when interest rates went down instead of up, profits plummeted and rents went up.

Other housing corporations were forced to step in to help repay the banks and to avoid the whole social housing sector collapsing.

The resulting increases in social housing rents have attracted other European investors and spurred a wave of social housing sales.

Every summer coachloads of tourists are bussed into the small town of Delft, near Rotterdam, famous for its distinctive blue and white pottery. This year many took a detour to explore the latest innovations in water-based living.

Miranda Boekee's home was the main attraction. The nail studio entrepreneur was delighted to throw open her doors and have them traipse around her floating living room.

"We save money on our energy bills. During the summer our water is naturally heated and in the winter it's cooled," she says.

The architect, Koen Olthuis, s us on the shore. He is currently juggling glamorous water-based projects in Miami and Dubai. He acknowledges that these floating villas are not an affordable option for your average buyer - but rather, he says, a model for mass producers to aspire to.

"If you want to make these homes more affordable you should build in higher densities, so build houses in a row or floating apartment buildings," he says.

"I think these kind of houses are important because if you really want to see this grow, to have many more of these houses, and make them more affordable, then you should build those [floating villas] because seeing is believing. I think this is the next generation of floating houses."

It is not just the problem of affordable housing that building on water could help address.

Around the world more than three billion people live in coastal city areas that are at risk from rising sea levels. Some flood-prone locations such as Lagos, Mumbai and New Orleans are deriving insights from the Dutch experts, while London is working with Dutch developers to create its first floating community in the Royal Victoria Dock.

One of the most valuable lessons to be taken from the Dutch experience is that investing in floating living spaces could ultimately prove to be more cost-effective than mopping up after floods.