Try Hemp For Green Construction

[Ganjarden]

I was watching an episode of Grand Designs and saw someone using hemp and lime in their construction.

I haven't seen this before and it was said that it was a sustainable and environmentally friendly form of construction.

What exactly is it?

Hemp is a crop, traditionally grown for paper manufacturing, which has seen increased interest as a sustainable building product. Despite having been outlawed for a time in the US and UK for its tenuous links with marijuana growing, hemp is now being grown throughout Europe for use as a construction product. It's perfect as a break crop as it's fast growing while also being surprisingly good for the ground itself. Increasing the amount of hemp grown could give benefits to the consumer and to the farmer.

Hemp lime uses a specially prepared hemp product as an aggregate and combines it with a lime based binder to form the construction material. The resulting construction material is flexible, sustainable, provides good acoustic and thermal insulation and has very low embodied energy in its manufacture.

Typically hemp lime construction is cast around a timber frame to create a solid wall, it can however also be used for insulation in roofs, underfloor insulation, solid panels, floor screed and as plaster.

The hemp lime wall is then sprayed with a lime render to finish and if this type of finish is too rough for you, cladding can also be added to the frame. Its flexibility means that the product moves with the construction which results in very little cracking and its ability to stick to most building products allows huge variation in terms of construction shapes.

Hemp lime is especially suitable for use in renovation where its ability to stick to most surfaces serves it well in the irregularities of old buildings. Its breathability also allows it to cope better than regular plasterboard with the general challenges of wall dampness.

If you're a self builder there are some basic points to note in using it as a construction material

1. Do not attempt to construct using it in temperatures less than five degrees as it affects its setting

2. Weather protection to the lime hemp is necessary, and can be achieved in a number of ways such as using a render, cladding etc.

3. It presently has to be mixed on site, but pre-made hemp lime blocks are available and studies are underway into a hemp lime spray.

While the U-values of hemp lime may be on the conservative side, its low embodied energy, sustainability, renewability, breathability, good acoustic performance and warm feel make it an excellent construction material choice if used correctly.


News Hawk- Ganjarden http://www.420Magazine.com
Source: Independent.ie
Author: Darroll Holden
Contact: Independent.ie
Copyright: 2009 Independent.ie
Website: Try Hemp For Green Construction