They say constraint breeds creativity, and anybody looking to get into home ownership will be extremely familiar with the constraints that go with it. Architectural, construction and design innovations therefore have a huge role to play in getting roofs over heads, particularly when it comes to the world's poorest and most vulnerable. Here we take a look at some clever solutions to low-cost housing, including a few whose appearance far outstrips their price tag.

International statistics on homelessness are hard to pin down, because the very definition of the term varies between countries and much of it is hidden from view. But as a guide, the UN in 2005 undertook a global survey and estimated there to be some 1.6 billion people in inadequate housing and 100 million completely homeless people around the world.

Architectural trends like shipping container homes, modular structures and prefabricated dwellings have driven down the costs of house construction. Not to the point where homelessness will be eradicated entirely, but they have made home ownership a new and real possibility for a great deal of people.

Some of the concepts showcased here won't make it beyond the drawing board, but all incorporate interesting ideas that place an emphasis on efficiency of construction and cost effectiveness. They also demonstrate how such priorities don't always have to come at the expense of aesthetics.

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