Top 10 Alternative Housing Ideas

Nope, these aren't corn cobs. In green construction, cob refers to a mixture of earth and straw similar to the adobe homes you might see in the American southwest. Cob is an inexpensive, versatile material that allows builders to shape walls any way they want. While adobe is usually formed into bricks or blocks, cob is unique in that it's applied in large handfuls to form the structure.

Typical cob homes have unique, rounded features and almost look like they're made out of clay -- that's probably because they basically are! And cob is sturdier than you might think: Some cob homes built in England in the 19th century are still around today.

Bales of straw are also natural and inexpensive, and they provide excellent insulation. This makes straw-bale construction an economical green-building method. Since straw is a byproduct of grain farming, it often goes to waste, so using it in construction is a great way to reuse it.

Straw-bale construction is versatile, too. Since you're using the straw bales either to construct the frame or as insulation in conjunction with a wooden frame, the house itself can look however you want. And no big bad wolf is going to blow down this house of straw -- in most straw-bale construction, recycled steel beams or bamboo rods support the bales.

Shipping-container homes are gaining popularity. They can be cheaper to build than conventional homes and use fewer raw materials, and the finished structure has a modern, industrial look. Green builders can use one shipping crate to build a relatively small, single-family dwelling or combine crates for a larger house or even bigger structures, such as apartment buildings and schools. For example, Container City in London, built in 2001, turned 20 shipping containers into 15 eco-friendly live-and-work spaces [source: Trinity Buoy Wharf].

Their efficient size makes these mini-homes inherently green, and some enthusiasts even make them even more eco-friendly with green insulation, radiant heating, solar panels and rainwater-harvesting systems.

Architectural firm I-Beam Design came up with the idea of creating homes out of wood pallets as an affordable and eco-friendly solution for disaster relief housing. They first designed the pallet homes as an entry in a contest to solve housing problems for refugees in post-war Kosovo, but you can also use pallet wood to create something more permanent.

Used wood pallets are readily available and cheap. A small 10-by-20-foot (3-by-6-meter) shelter would cost around $500 and require about 80 pallets [source: Embrey]. It's easy to imagine combining several of these small shelters and reconfiguring them to form a unique, energy-efficient home. And if you do decide to remove the building at any time, the materials are easy to recycle.

A green roof is more than a cool architectural feature. It can help manage storm water runoff by providing a permeable surface, and it can help offset the urban heat-island effect. Rather than absorbing and storing heat like a regular roof, a green roof reflects heat and can help lower a building's cooling costs. They are also great insulators and can reduce both air and noise pollution.

On a home, the most practical type of green roof is an extensive roof, which can support a variety of small plants. Because these roofs are designed to support only a few inches of soil, they don't require much maintenance, and you'll have a new kind of eco-friendly garden to enjoy.

Living walls are as beautiful as they are functional. These vertical gardens are able to support a range of plants from succulents and mosses to edibles. On top of turning otherwise wasted space into green space, a green wall on the south side of your building helps reduce cooling costs in the summer.

Most green walls are constructed using a modular design, which not only makes them easier to build, but also allows you to create interesting patterns and designs by mixing and matching different plants. Imagine growing fruits and vegetables right on your own home -- it doesn't get much greener than that!

While an Earthship may sound like some kind of local UFO, it's actually an eco-friendly form of housing becoming more popular around the world.

Michael Reynolds, who designed the first the Earthship back in the '70s, envisioned a home that reduced waste and energy consumption. Typically, an Earthship's frame is constructed from reclaimed tires and an eye toward maximum energy efficiency. Reynolds' ultimate vision was to create off-grid communities of Earthships, so these homes generally rely on renewable energy rather than conventional electricity from the power grid.

These homes' construction also tends to include old bottles and tin cans that would otherwise end up in landfills. And many Earthship owners go even greener by creating indoor gardens for growing their own food. Today, in addition to single-family Earthships, there are also Earthship neighborhoods and even condo complexes.

Want an eco-friendly way to get rid of those empties after a party? Tito Ingenieri built his Quilmes, Argentina, home out of 6 million empty glass bottles. He sets the bottles in concrete to create a light, airy space that's a testament to the amount of empty bottles that go to waste. Friends and neighbors have saved their bottles for Ingenieri over a period of more than 19 years, and he says that his home "doesn't belong to me, but to many people in this town. They say this is an ecological house, as it is made of bottles from the street, and now the streets are clean" [source: Alvarado].

While you may not want to spend years gathering (or drinking from) enough bottles to build a home, you can start smaller with a bottle shed or garden wall.

Traditional concrete is very energy intensive to create, so one Asheville, NC, company is looking to change that. Hemp Technologies developed an alternative concrete, called Hemcrete, out of hemp, water and lime that's more durable than regular concrete. Because it's currently illegal to grow hemp in the U.S., Hemcrete costs more than regular concrete, but since the material insulates better than concrete, you make that up that cost over time in energy savings.

Walls constructed with this material are also resistant to fire, mold and insects, and some researchers think that it may even last as long as 700 to 800 years [source: Lawrence].

Modular homes have come a long way from the types of prefab houses that you're probably familiar with. Many modular home companies are creating kit houses with a modern look and an environmental twist. Some buy the smaller kits to build guest houses or outdoor offices, but for minimalists and do-it-yourselfers, modular homes make perfect primary residences.

Eco-friendly modular homes are often smaller than traditional homes, so they use less energy to heat and cool. Also, since the pieces are all manufactured to fit together perfectly, prefab homes minimize the waste that goes along with a typical construction project.

To learn more about green construction and eco-housing options, check out the links on the next page.