Light weight construction materials will appear

Gregory Benford : science fiction author and astrophysicist
Research may allow us to do incredible things with super-lightweight materials. The starting point may be the “aerogel” compounds now used mainly as gas or moisture absorbers. These substances are composed of innumerable minute bubbles like foam, stuck together to form a solid mass, some of them are 20 times lighter than water.
Imagine a house built of such bubbles instead of heavy brick, wood, glass, and plaster. Its cost would be little because there would be little material needed in the first place, and no heavy materials to transport and erect. Instead of expensive foundations, simple wind anchors would hold the house in place. The walls could be formed in place with a spray gun, and the roof arched over, integral with the walls. Our bubble house is automatically sound- and vermin-proof, insulated against extremes of temperature, and has no heavy elements to collapse in an earthquake. It is fireproof. Part or all of the walls could be left transparent so that with draperies and shades you could arrange your windows to suit your convenience, and change them when you wish. With the chief use for cheap lumber eliminated, our forests would become parks and game preserves instead of useless cut-over land.Twelve men could lift an aerogel-constructed house that would weigh ten tons if made of materials in use today

GREGORY BENFORD, Popular Mechanics, (2012), "The Future That Never Was: Pictures from the Past', [online], Available: