Categories
Construction Hemp

Interview with Ian Pritchett of Lime Technology

So pleasing to see a pleasant person who loves and believes in what he does. An interview with Ian Pritchett, Managing Director of Lime Technology:

Categories
Construction Hemp

Hempcrete Building

Informative video which did a great job of putting images to words:

Categories
Growing Food Hemp

Information on Harvesting Hemp – Part 1

Inspiration

I am currently living with an inspiring notion that we will (1) be able to grow the hemp needed to build our future home and (2) that we will have enough land to grow a houses-worth of hemp every year so that someone else will be able to do the same.

Introduction

Though I have to say that the more I explore the world of Hemp the more doubts about this being a feasible goal. At the end of this post you will find some links and PDF’s I read and that led to my current understanding.

Hemp seems to be a relatively easy crop to grow. It’s strong, it doesn’t require pesticides, it grows pretty fast (~4 months) and it even renews the land in which it is grown. The more substantial challenge is harvesting and processing it.

Three Parts of Hemp

There are three parts to the hemp plant – each with it’s own uses:

  1. The seeds can be used for all kinds of food products, oils and other medicinal by-products.
  2. The fibers have all kinds of industrial uses (from clothes to cars) – they are the middle layers of the stalk covered by a thin protective layer.
  3. The hurd – the wooden core that is left over after the fibers have been extracted – which is the part popularly used (together with lime) for construction (although I have come across information that indicates that it is possible to use the fibers and curd together for construction – which means that they don’t need to be separated).

Some Hemp Harvesting Facts

  1. Seeds and stalk don’t mature together – they are (or at least should be) harvested at different times. Both the seeds and the fibers have (different) optimal times for harvesting – beyond which both lose some of the potency and qualities.
  2. The seeds don’t mature all at once – they tend to mature in two cycles. Harvesting time is when you think you can harvest the most mature crop (when some of the seeds may have decayed or lost their potency and others still not quite matured).
  3. Hemp is a tough plant – so you need resilient and strong harvesting tools. The strength of the fiber means it’s hard to cut down and the length of the stalk means it will catch on to and jam any moving part it finds (for example – combine machinery) – which means that you either need powerful harvesting machines – or that harvesting may be slow and tedious.
  4. Hemp is a tall plant (much taller then wheat or barley) – which means you need harvesting equipment that can reach up high.
  5. When the stalk is cut, it is useful to do it in such a way that it is then easy to collect into bales – if I understood correctly what this means is that the harvester needs to leave the cut stalks uniformly oriented on the ground.
  6. The stalks should be cut as long as possible – long fibers are generally better and more useful then shorter ones.
  7. It is possible to harvest both seed and stalk. Seeds go first (duh!) – but then you not only need tall harvesting equipment but it also needs to be sharp and fast spinning – so that the stalk is cut cleanly – leaving long fibers in tact.
  8. The primary processing for seeds is removing them from their shells – I still don’t have information on how that is done.
  9. The primary processing for stalk is separating the fibers from the wooden sheathe (this is called “decortication”- whichI am guessing comes from the idea of removing the core and, apparently, originates from a medical surgical process of separation). There are numerous methods for this – but generally they seem to be divided in two: industrial processes and organic/natural processes. I am less interested in the industrial aspect so I focused a bit more on the natural processes. Apparently the idea is to use water to cause decomposition of a kind of “glue” that keeps the fiber and curd attached. Usually natural dampness like dew will do the trick. You need to keep an eye out on the crop until separation begins – then you need to let it dry for a few days. I am not yet clear on all the details of this process.

All these facts seem to eminate from an industrial/financial view point. They are focused on creating optimal yields and financial returns. If harvesting and processing hemp can only be done using heavy and expensive machinery – that means that growing just a few acres or a hectare of hemp isn’t feasible.  I was somewhat discouraged by this. But …

Since hemp has been grown for hundreds of years (if not thousands) I am sure there is much knowledge on how to do it on a smaller scale – for home needs but I haven’t been able to find any information on this yet. It may require more manual labour but I am confident it is possible. Our needs are humble – maybe to build another small structure for meditation, enough seeds for eating, making oils … the needs of a small family.

I’ll continue to look for more home-oriented information on this – I promise to share it here when I do find it.

Resources and Further Reading

Links:

PDF’s:

Categories
Construction eBooks Hemp Resources Useful Websites

Must Read on Hemp

I recently came across this excellent and free eBook on Hemp Lime Construction. It is published by a UK organization called “National Non-Food Crops Centre” – a name that was a huge lesson to me in it’s own right. In my mind “crops” was obviously associated with farming and food. I now know that there is an entire domain of farming for non-food crops. Two prominent example of non-food crops used in construction are Strawbales and Hemp. I am looking forward to learn what other surprises crops hold in store for me 🙂

Back to the book – it is a must read for anyone (home makers, architects, engineers, farmers,governments … ) interested in working with the magical substance that is hemp.

Here is a summary, quotes from the book itself, on the advantages of Hemp construction – just to give you a motivating flavor:

  • A means of achieving energy efficiency
  • A way of providing thermal mass
  • A breathable material which can help to create healthy buildings
  • Use of a material which is renewable and does little environmental damage
  • No pollution and no problems at end-of-life disposal
  • 95 Crop-based material which helps farmers and is a good use of land
  • Helps to facilitate healthier buildings
  • Offers the possibility of sequestering carbon into building fabric
  • Hemp lime has the ability to make an impact on the future of sustainable building by reversing the damaging effects of greenhouse gases. It is claimed that hemp lime can lock up approximately 110 kg of CO2 per m3 of wall.

I am sure I will be referencing this book often here on Bhudeva 🙂

Categories
Construction Hemp

Building with Hemp

Three great videos introducing building with hemp: