With today's growing concern for the environment, green construction market is gaining immense popularity. According to the Consortium for Research on Renewable Industrial Materials, 1.7 million buildings made with traditional steel and concrete consumes the equal amount of energy used for heating and cooling 10 million houses each year. Natural building materials demand minimal refining or processing, while reducing detrimental environmental impacts. Eco-friendly homeowners and construction corporations are adopting sustainable home-building methods and materials. Green building is constructed with natural, renewable, and locally available materials. Industrial or man-made products are strictly avoided. Natural, biodegradable materials reduce level of toxicity in the indoor environment of the green buildings. As a bonus, many of these materials are energy-efficient, inexpensive and easy to use with little construction knowledge. Hemp is one such green building material which is gaining immense popularity with architects, designers and home builders in the US.
Hemp, lately has been strongly recommended in place of timber due to its eco-friendly attributes. Hemp fibers are very strong and elastic which makes them ideal in using for canavs and cloth making. The same feature of Hemp makes the Hemphurds with over 60% cellulose, which can definitely reduce landfills of plastics. It is versatile, environmentally-sound building material. Hemp building is up to 7 times stronger than those made of concrete. The buildings made with hemp are half as light and three times as elastic compared to concrete structures. Hemp buildings are resistant to stress-induced breaking and cracking, often encountered in earthquake-prone regions. Hemp building materials are self-insulating, resistant to rotting, fire-proof and waterproof. Hemp takes only 100 days to grow in comparison to timber, which takes around 100 years to reach same volume. Hemp grows in abundance without the additional maintenance like cotton of insecticides or herbicides and requires very less irrigation as compared to other plants. Hemp houses need less energy to heat than conventionally constructed homes as it is a good insualting material. Use of hemp during construction, creates less waste compared to timber. Over the years, depletion in rainforest cover, has resulted in the the destruction of many ecosystems, endangered flora and fauna, and added fuel to the already growing global warming situation. Many parts of rainforests are cut down regularly for timber thereby creating a serious threat to the ecological balance. Replacing timber with hemp for building can help in reducing the deforestation, protecting the forest cover to a large extent.
Hemp comes under the category of bast fiber crop. Processing of its stems, results in two different materials i.e. Hurds and Fibers. Hurds are used for creating different types of products resembling wood such as roofing tiles, wallboard, fiberboard, insulation, paneling and bricks. The fibers are used in place of straw during bale wall construction or blended with mud while building cob style construction. Hemp hurds make a good material for constructing foundations. Lately, use of hemp as an insulation product has increased due to its thermal resistance quality, capacity to absorb moistness, resistance towards attack from mold, pollutants and dust. Hemp is known to be one of the best naturally available paint bases. Professional hemp paint manufacturers vouch for its durability and ability to coat evenly during painting. Hemp hurd covered with coal-based bitumen are dried to form thermally insulated floor.
Hempcrete known by other names such as Hemcrete, Canosmose, and Isochanvre is made of hemp hurds, sand, plaster, lime and some amount of cement and water and sprayed onto timber, stone. This mixture is then made to set for around 24 hours and takes a week to become completely hard. The blend thus formed is highly durable and strong like a stone and is known as "hempcrete". One of the brilliant examples is the 6th century hemp-reinforced bridge located in France. Hemcrete is a good insulator, fire retardant, waterproof and resistant to rot and rodents.
The Suffolk Housing Society in UK estimated that the actual cost of hemp construction was £526 per square meter compared to £478 for traditional concrete construction. Hemp bricks are used for these green buildings. They are low cost building material but incredibly strong, like concrete. Dried hemp stalks are mixed with lime and water to form bricks. The hemp bricks are used inside a wooden frame to construct a building. These green buildings remain well insulated throughout all the seasons, which decreases the energy costs. A house owner spent $133 a square foot to build a 3000sq.ft hemp home in Asheville, North Carolina. This is double the cost of building with the regular materials. The building costs are currently higher, especially in US, because of the ban on industrial hemp and the materials have to be imported which results in a higher cost per square footage. Other countries such as Canada are ahead of US, in this aspect and are exporting Hemp. The costs of Hemp materials will come down with the increase in number of buildings that use Hemp. But for now, Hemp remains expensive than the traditional building materials.
With many countries lifting the ban on use of hemp and its products, a lot of companies have started producing hemp building materials. For a btter understanding on how Hemp is being used by many building industries , visiting the International Hemp Association can give you a better idea on the developments happening in this area. Some of the prominent players in the Hemp Building materials are:
For additional information on Hemp, click on the links below: