Construction Hemp

Chronological Images from Nauhaus

It seems that Clark & Tim, the guys who wrote Building Green, moved in the Passivhaus direction. They have a project called Nauhaus where they are attempting to bring together their past experiences with the Passivhaus standards.

I believe, as I have written before,  that the Passivhaus standard is not a practical nor sustainable form of construction – though there are some excellent and applicable ideas and inspiration to be drawn from it. The Nauhaus was built with hemp, which from the theoretical (at this point) knowledge I have gathered simplifies, ecologizes and reduces costs of many construction aspects. Yet because of Passivhaus standards Nauhaus also reintroduces many complications which I find … uninspiring. Just this morning I was reading their chapter on building a green roof, then I came across the massive, industrial insulated crane-lifted panels they used in the Nauhaus project. Though I can appreciate their efforts to move forward and improve … it feels to me like they took a wrong turn somewhere … I think Passivhaus had something to do with it.

I was surprised to see in some of the images the Tradical procucts and then to learn that the interview I posted with Ian Pritchett was actually from the Nauhaus project.

Amongst the information on their website is an educational set of posts with images showing the contruction chronology – from foundations to a completed building. At this point in my education, these documented processes are extremely useful and rewarding. The chronology starts at the end of this page – from where you can scroll up and forward in time to see the project progress.

My main take from these images is on some thoughtful tricks on how to efficiently prepare and install formwork for the hempcrete as you can see here and here:

And also this super-simple ingenious carpentry lesson from Tim – as he creates a simple tool for measuring and placement of formwork from here.

Construction Growing Food Hemp Hemp Research Resources

Self Grown Hemp for Construction

Wouldn’t it be ideal if you could grown your own hemp and then use it to build your home? 1 or 2 hectares of hemp stalk is potentially all you need to harvest enough building materials to build a house. Imagine that – growing your own house!  … but it isn’t a simple thing to do.

The hemp plant has four elements: seeds, leaves, fibers and a wooden core. The part you need for construction is the wooden core – also called the hurd or shiv. Separating it from the other elements of the plant requires effort. You need to grow the hemp, deffoliate it (remove the leaves) before harvesting, harvest or remove the seeds, harvest the stalk, let it ret (start decomposing so that the fibers can be separated from the hurd) and then decorticate it.

This finally step of decortication seems like the greatest obstacle – this is the process of separating the fiber and the wooden core. It can be done either through massive manual labor (of which I don’t yet have all the details – but it involves collecting the harvested stalks into small bales and then beating them to separate the fibers and wooden core) or in an industrial process. The indutrial process is usually designed to extract the fibers, the actual wooden shiv is simply a left over of that process.

It would be so much easier to grow your own construction hemp if decortication could be avoided – and this may be possible but my understanding is that it depends on the climate you live in. This research paper on Hemp-Concretes claims that it is possible to create hempcrete using both shives and fibers – BUT it is important to note that the research focuses on the structural aspects of the resulting hempcrete. It does not address the effect of fibers on insulation and breathability of the hempcrete.

Introduction of fiber to the hempcrete mix can cause humidity problems. When fibers are clumped together they tend to draw moisture and that is not something you want to happen in your wall. According to Steve Allin it is possible to add 5%-15% of fiber to the mix but not much more. This may be less of an issue in a hot and dry climate – but otherwise the risk seems unwarranted.

Maybe when the hemp industry matures it will be possible to cultivate stalks with very little fiber and a massive wooden core – which could then be used in whole? For now though it seems that self-grown hemp is not a feasibly reliable option for construction unless you have the means to decorticate it.

Books Construction Hemp Resources

Building with Hemp

There is only one book (worthy of being called a book) I know of (in English) – Building with Hemp by Steve Allin. It isn’t the one and only book you will need to actually build with hemp – but it provides the best overview, explanations and images I’ve encountered so far on doing so. It touches on many hemp-effected aspects of construction. You will still have to do a lot more inquiring and apply your own common-sense but this book will be an excellent road-map for you on your journey.

Blog On The Way

2 NGO’s and a Peasant Meeting

Last week we met with two inspiring organizations with whom we hope to collaborate in the process of creating our home here in Romania.

Habitat for Humanity Cluj

The first meeting with with Habitat for Humanity Cluj (English website, Romanian website) who’s mission is to provide decent housing where currently housing conditions are very poor. Here in Romanian they have a few house templates that they can build in a few weeks. They organize volunteers from around the world to come and partake in a quick and efficient building process. They also provide home owners with a  zero-interest loan at very small monthly payments (over as long as 20 years) to fund the costs of construction materials.

Our hopes are to both gain from their building experience here in Romania and to offer a shared learning opportunity on the benefits of building with hemp. We believe that hemp-lime construction can be a wonderful alternative with the benefits of simpler construction, better housing (insulation, air quality, durability) and ecological. A win for the organization, for residents of their houses and for the planet.

Eco Ruralis

Our second meeting was with EcoRuralis (English website, Romanian Website) who’s mission is to support traditional Romanian peasants (who represent ~50% of Romanian population) in the face of external forces of industrialization and commercialization (mostly originating from the EU) that threaten their survival and prosperity.

I realize that mission statement may sound petty and remote to non-Romanians so let me give you an example. It is now absurdly illegal for Romanian peasants to sell their traditionally developed and evolved seeds (over hundreds of years). Legal and commercial standards are pushing to replace traditional seeds with genetically modified industrial seeds. Such measures, together with beaurocratic hurdles required to selling their crops in local markets threaten not only their existence but an entire tradition of agrictultural knowledge.

A Peasant Meeting

EcoRuralis were extremely pleasant and generous with us. We immediately signed up as members and over the weekend they invited us to a member-meeting which took place in Calimenste (a 6 hour bus ride south of Cluj-Napoca). Not only were we welcomed in no-questions-asked, they also covered all the expenses in getting to and partaking in the meeting. We had a wonderful time and met inspiring people.

It is so exciting  and comforting to know that we have access to everything we need (from knowledge to seeds) to create up our own farm. Though we are currently focused on the construction aspect of our home we are also on our way to becoming peasants and taking up healthy traditional farming.

Another interesting shared interest is hemp-construction. Hemp was once a popular crop here in Romania and we hope it will be again. Everyone was very curious to hear more about hemp construction. We can’t wait to invite them all to see when the house is actually built and then to be our guests and experience what a wonderful quality-of-life it can afford.

Everyone was so kind and so generous. With some translation help I said to them that after almost 40 years of life I am for the first time beginning to feel I am at home.

Growing Food Hemp

Evolution of Hemp Processing – A Story in Images

I came across this PDF presentation on the European Indutrial Hemp Association website – it has some great and educational images in it on the evolution of hemp processing.

Construction Hemp

Look Out Romania – Here Come’s Hemp

We aren’t the only ones trying to do this … as I write these words Andreea is making calls … this is so happening 🙂

… this is Teodor Pop of Lux Perennial
… which are associated with Hemp Technologies USA
… which are associated with Lime Technologies UK.

Construction Hemp

Modece Architects

It’s been over a week that I’ve had the website for Modece Architects open in my browser. I really enjoyed the website – it feels like an authentically green site – one that actually walks the walk. Particularly I’ve browsed back and forth endlessly in the sustainable-construction gallery which has been quite an eye opener. For example …

This image hints at the potential of using quality timber framing together with hemp construction – which I was just wondering about…

or this image that demonstrates that loose hemp!!! can be used in floor insulation:

… or this image of a do-it-yourself solar panel:

… honestly, every picture in their gallery is like a magical doorway into knowledge.

But what really tickled my fancy was that as I was revisiting that must read book on hemp-lime construction I recommended a while back – I made the connection that the hand-drawn illustrations starting on page 31 were contributed by Ralph Carpenter of Modece Architects … and I am thinking “yeah, that’s the website I’ve got open in my browser” … so it seems that the world of hemp-lime construction is still a nice and intimate community 🙂 Great fun!!!

Growing Food Hemp

What About Growing Hemp?

Growing Food Hemp

What Happened to Hemp in Romania?

Hemp is currently our preferred method of construction so naturally we are looking around to see where we can find it. Eventually we also hope to grow it for personal uses for food, oil, fibers and to provide building materials for other Romanians who may wish to build with Hemp.

Here is what we know:

  1. There used to be a promising Hemp industry in Romania – very little remains of it.
  2. The soil and moisture conditions in Romania are excellent for growing hemp.
  3. We tried contacting Advantages (hemp naufacturer from Timisioara) and were told they no longer exist.
  4. There is an impressive international! Romanian company in Solanta called Canah that manufacture wonderful hemp-based food-products.
  5. Though they would like to rely on local (Romanian) supply Canah imports most of its raw materials.
  6. It is (theoretically) possible to grow hemp in Romania – for which you need an approval in advance and additional monitoring while you grow and harvest the crop.
  7. Every year, just before Christmas, hemp seeds appear in Romanian markets – they are used to bake a traditional holiday-cake – it is unclear where these hemp-seeds come from (one speculative theory is that it comes from Moldova).

One of the (numerous) ecological aspects of hemp is that it can be grown (and processed) close to where it is actually needed. This reduces the need to transport it across great distances. Transporting it leads to carbon emissions which defeat it’s ecological benefits. We are making an effort to find a Romanian farmer from whom we can purchase the hemp we need to build our home.

Though we will do our best to leave as little ecological damage in getting our hemp it would be an ironic-shame if we had to take our money elsewhere (Hungary, Germany, Austria, Sweden, Holland, UK, etc.).

So my question to anyone who happens to read this and know something about it is what happened to Hemp in Romania? Why was it illegalized? Why was a promising industry shut down? Who could possible havy gained from this? What can be done to fix what looks like a tragic mistake for the Romanian economy?

Construction Hemp



Passivhaus is one of the terms out there in eco-green-sustaintable building land. It may look like its spelled wrong but that’s because its originally from Germany. It represents a very strict and high standard of energy efficiency in a building. It isn’t (yet) an official requirement or standard but it is gathering momentum as an unspoken standard.

There are three complementary core ideas behind the idea of a Passivhaus:

  1. Complete and thorough thermal insulation of the house which prevents conductivity of heat from the inside-out or the outside-in.
  2. Complete air-tightness which prevents exchange of heat through air leaks (windows, doors, pipes, chimneys … every opening needs to be sealed!).
  3. An efficient ventilation system that both exchanges air (from the outside and the otherwise airtight house) and does so without losing heat.

This is one of those images that is better then a thousand words. The apartment building on the left is standard/traditional building while the apartment building on the right is built according to the Passivhaus standard. That’s the bottom line of Passivhaus – keeping the heat from escaping means you need to expend less energy to heat the inside.


I have come across Passivhaus numerous times in recent weeks and my recurring personal impression is that it is too extreme:

  • It seems like more of an academic indulgence then a practical construction practice.
  • It’s objective and success is measured in a single number – the amount of energy needed to heat a square-meter of space.
  • It demands rigorous builing disciplines which require uncompromised excellence in construction.
  • It demands the use of specialized insulation materials which can be expensive (especially if you consider the ecological foot-print involved in manufacturing them).
  • It creates a house that demands constant attention, maintenance and proper use by its residents (every window opened and every hole drilled in the wall is a potential energy hazard).

All of which results in a delicately balanced system: if it isn’t absolutely sealed, perfectly ventilated by a carefully installed system and properly used it just won’t work. There is no room for error. This maybe OK in a scientific experiment but not so for life, nature and people.

In any case it doesn’t feel right for us: we have a limited budget, average construction capabilities, standard building materials, etc. We are going to do the best that we can with what we have. It’s an 80/20 kind of thing – where 20% of the effort takes you 80% of the way you need to go and it would take another 80% of effort to go the rest of the way. We’re aiming for a good middleground – pushing the limits of what we have – but that, by definition, is not enough to go for 100%. Passivhaus is uncompromising, but we live in a reality which demands compromise.

“A passivehouse is cost-effective when the combined capitalized costs (construction, including design and installed equipment, plus operating costs for 30 years) do not exceed those of an average new home.”


I am hesitant to relate to this statement as that may give it unwarranted legitimacy –  cost is just too narrow a perspective to view ecological housing. But if I do meet it head on, as is, I would say that it sets its sights much too low. I hope to build a house where the combined capitalized costs are much lower then those of a new average home (whatever that is). I also hope to build a house who’s qualitative effects (both for us and others) far outway it’s economic effects.

Maybe Passivhaus is, for the time being, a high-end building experiment? Maybe in time it will spawn accessible, affordable and feasible techniques, solutions, technologies, practices … that can become a defacto standard that simply makes sense to follow? For now, it is out of touch with us and our needs.


Having said all that exploring Passivhaus has brought to my attention a factor I had not taken into consideration in all of my energy research: Indoor Air Quality. I have been following a very basic intuition: “generate heat” in trying to solve a problem we’ve been having for many winters: “being cold”. Most of my attention has been on how to preserve and generate heat (space and water) effectively.

I had not given any thought to one of the central themes of Passivhaus: quality of air. Quality of air (assuming there is good ventilation) is strongly effected by humidity … and humidity effects the overal experience of temperature … cold is much colder when humidity is too low and heat is much hotter when humidity is too high. I have experienced the effects of humidity in warm and cold temperatures in Israel and I have seen it (as accumulated moisture and mildew) in almost all Romanian homes I have visited.

I don’t know yet enough about ventillation and humidity.


One of the much praised qualities of hemp masonry is it’s breathability. It seems to have a natural tendency to absorb and expel unneeded moisture. I don’t yet have enough information on the overall effects of hemp on moisture, ventilation or quality of air indoors – but I do have a good feeling about the effects of hemp!


Following are some of the resources I came across and consumed in trying to understand Passivhaus: