Talk for the Official Language School of Sabiņanigo

13 February 2017


Hello, Good afternoon and welcome to my talk about my experience of building my home and managing a beautiful piece of land in the pre-Pyrenees. Thanks to the Language School for having me.



At first glance it may seem like a typical unrealistic dream of a young schoolboy, building your own house and moreover: using straw bales seem to come directly from the fairy tale about the three little pigs (which ends badly for the straw bale house, by the way). But what I discovered was that you can really join the two extremes: on the one hand a fantasy, a dream from another legendary, archaic world and on the other hand the reality of modern, internet-inspired technology and communication. Because that was what happened: when I wanted to leave city-life and start a new life in the country I looked on the internet and found that there are actually many realistic possibilities to do things yourself, even if you are not very professional or technical, like me. I graduated as an agricultural engineer but have been a teacher of English for the most part of my professional career. So I am not really prepared for constructing and I am neither very handy but it can be done. That is what they say and that is what I have discovered. More than anything else it is a question of dedication, getting informed, taking your time, and learning from your mistakes.

So this is what happened: after living for two decades in the city of Zaragoza, I wanted to move to the country and in 2006 bought a beautiful piece of terrain in the pre-Pyrenees near Graus and Barbastro in the little town of La Puebla de Castro. Being an 'aficionado' of botany and spontaneous vegetation I immediately started to manage and stimulate wildlife on the terrain. I read about all possibilities and techniques, mostly on the internet and in 2008 started building a first small garden house, as a rehearsal for something bigger. It was finished in 2010, and after a two-year break I amplified this house with a new wing which became my actual, official home of today.
A quite detailed and chronological story of the process can be read on my personal weblog: Nature Switched On. (if you type this without spaces in Google you will directly be transferred to this blog, there is also a Spanish version available).

In this talk I am not going to retell the whole story over the years but instead will focus on the following aspects, techniques and systems:


-    Building with straw bales

-    Plastering the walls with earth

-    Earthen floor

-    Compost toilet

-    Solar shower, solar washing machine, solar panels

-    Green roof with Sedum plants

-    Permaculture vegetable garden and wild garden with ponds


Building with straw bales.

So why a straw bale house? Ten years ago it seemed to me ideal for three reasons: it is economical, it is ecological and it can be built by a non-expert (a layman) like me. Now, ten years later, I can affirm these characteristics although I must confess there were some mayor changes, adaptations and mistakes. But: you have to face (confront) the challenges, you have to learn from your mistakes and, very important for a self-builder, don't hurry and take your time.

The building method is relatively simple and straightforward: between some wooden frames the straw bales are piles up, as if they were bricks. Special reinforced wooden frames are used for windows and door. Under and on top of the walls other wooden structures, ring beams, are placed so the wall becomes a kind of sandwich with the straw bales pressed between these frames with special white straps (Cordstrap).


This is in October 2008. These straw bale walls were erected in one day with the help of friends and neighbours. On the left the wooden structures that go on top of the walls. In the centre two people are busy with the tailoring of different sized straw bales.

The same straw bales serve quite well as scaffolds. The white cordstraps are tensed with a special device.

There are certain limits to the distribution of windows in a wall and also to the maximum length of the wall, which is about 6 straight meters. If you want longer walls you have to introduce corners or make curved walls. And that was exactly what I did when I amplified the garden house with a new wing in 2012. Not only are curved walls more stable, they also add a special aesthetic quality to the new house.
The new wing was a direct result of the success of the first garden house and used many of the proven methods. But now I was going for an official home with a legal permission so I employed an official architect. This was Petra Jebens, a quite well-known personality in the world of alternative and ecological building.

Here an image of this new wing in July 2013. Because it is partly built into the ground special techniques were used against humidity and to ensure that the straw bales are at least 15cm above ground level.

So building with straw is cheap and relatively easy but why is it ecological and sustainable? For different reasons: straw is completely biodegradable and recyclable, it is locally produced (saving fuel), in fact the bales come from the neighbouring cereal field (barley) and straw offers a tremendous insulation of the walls, saving a lot of heating energy.


Plastering the walls with earth.

Straw and earth form the ideal marriage: earth sticks very well to straw, it extracts and regulates humidity, strengthens the wall and gives it a nice, smooth look. The earth in our case comes from the same spot. It is very clayey and needs quite some sand to avoid cracks. You have to mix it mostly with your feet and you use your hands to apply the mixture on the walls so it can be a quite laborious  job but with a group of friends it can be quite entertaining. Clay or earth doesn`t stick to wood so you have to use cloth and wire mesh to make a bond  which also serves to mold corners and curves.

My brother and his family are busy with the plastering of the interior walls of the garden house in August 2009. They use a mixture of clay (earth), sand and straw.

This is 5 years later, when the first layer of plaster was applied on the exterior walls of the new wing. Two or sometimes three layers were applied and then a final smooth one, applied with a trowel.


Earthen floor.

Taking advantage of the availability of so good and so abundant local supply of clay I decided to install an earthen floor in the new wing. So, on a bottom layer (foundation) of gravel  and a sheet of plastic against humidity, I piled several layers of a mixture of clay, sand and straw, similar to the mixture on the walls. It is actually a kind of adobe. And then, for the final touch 4 layers of linseed oil with increasing quantities of turpentine. The result is quite satisfactory, taking into account that I am not an expert. It`s not perfect but a touch of ruggedness  is OK in this context and environment.

Here the installation of the floor. The wooden boards serve to maintain everything level.

Half a year later, painting the floor with linseed oil and turpentine. The walls have been painted with three layers of lime wash.


Compost toilet and grey water.

The little shed  was built initially for temporal usage, until something more sophisticated was built inside the main house. But it works so fine and effective that I decided to prolong its life. The idea is really simple: instead of pouring water after its use, two handfuls of ground straw are thrown into the bucket. In this way, bad smells are practically inexistent and at the same time you get a good mix for composting and you save a lot of clean drinking water. When full the bucket is emptied on a pile of compost for the vegetable garden. For hygienic and safety reasons it's recommendable to let the compost digest the material for at least two years. The system worked for centuries on a vast scale in China and a reintroduction of the system, in one way or the other, at least in the countryside, would save an incredible amount of water and probably also of fertilizer which can be substituted by the compost.


In the image an impression of the compost shed. Conceived initially as temporal I used straw bale walls without plastering. After almost 10 years the bales are still in good shape and will get along for another 5 or 10 years. The roof is covered with an black, waterproof EPDM sheet and has a vegetation of Sedum plants. The north face is now covered and relatively well protected by Ivy. The Rose on the left is spontaneous and wild, the one on the right is of course a cultivated variety (Paul's Scarlet Climber').

Other waste material that has to be treated are the grey waters of the washbasin and the shower. Here also I tried to implement a simple and solid system, in this case a filter pond. It consists fundamentally of a waterproof EPDM sheet buried into the soil and filled up with successive layers of sand and gravel. It is recommendable not to cause any layer of water to be visible on top, to avoid mosquitoes in summer. The grey waters are spread out over the pond and are treated by the bacteria and algae that develop spontaneously in the substrate. You need some three or 4 square meters with a depth of about 60cm for 1 to 2 resident persons. After some years now I can testify that the system works: there are practically no bad smells and the vegetation develops nicely. I have to comment as well that we always use biodegradable soaps and washing powder.

An impression of the filter pond vegetation with some typical aquatic plants like mint and loosestrife (=Lythrum salicaria).


Solar shower, solar washing machine and solar panels.

The sun shines on most of the days in this region and you have to take advantage of that. Besides the usual solar panels for electricity I installed a solar shower in the greenhouse. It consists of a black tube of a total length of 70 meters, exposed to the sun, with a content of some 17 liters. On sunny days it can get as hot as 60 degrees. Sufficient for a hot shower of 5 to 10 minutes, but also to heat water for the washing machine. My washing machine works with the 700 watts that my systems supports, but it can't heat the water by itself, which would use at least 2000 watts.

The greenhouse is really a multi-function studio where I also cultivate garden plants and work in a do-it-yourself corner. It is partly built with plastered straw bales, double glazed windows and a sheet of transparent fiber as a roof.

The green roof with Sedum plants.

I am an aficionado of botany and natural vegetation and have always been fascinated by green roofs, which are quite fashionable these days, at least in countries like Holland, Germany and Scandinavia. Apart from aesthetics and botany they have quite some advantages: they protect the waterproof black EPDM sheet, they insulate the house against heat and cold and they work as a buffer of water, regulating the water drainage with heavy rains. In my case I chose a system with succulent, native  plants from the genus Sedum, (Latin for: Stonecrop). They are very resistant to cold and to heat, need little soil and practically no maintenance. So the roof has the typical layers of cloth (geotextile), poly-ethylene, waterproof EPDM and then a layer of about 6 cm of soil. This soil comes from the same spot where the building was erected, using of course the top layer with some organic material. Six centimeters don't seem very much but I was very grateful when I received the help of neighbor Angel with his excavator. Before the soil he had already lifted the incredibly heavy sheet of the black waterproof EPDM sheet.

I used 6 different native species of Sedum which developed each one of them in his own way. A surprise was the spontaneous appearance and development of the blue German Lily. It is really a miracle how such a remarkable plant can survive the long, dry, hot summers and offer every spring this blue show on the roof.




Permaculture vegetable garden and wild garden with ponds.

How lucky was I when I found this terrain, now more than 10 years ago, with such a good location and orientation with one of the most beautiful views imaginable over the Cordillera Pirenaica. Moreover it proofed to be an authentic botanical garden with more than 250 plant species that I have been able to identify so far, of which almost 10

species of Orchids. It is situated between a cereal field and a wood of oaks and forms a kind of semi-natural open park which I pretend to maintain and develop. The management consists principally of cutting the vegetation with a scythe and pruning of trees and shrubs. Also the two ponds in the centre of the terrain attract and stimulate wild life. Wild boar, deer, badgers and foxes are regular visitors and sometimes it can be a little bit too much, especially the vandalistic habits of the wild boar.


The resulting hay from the cutting goes directly to the vegetable garden which was placed in a relatively fertile area near the house. In this vegetable garden I try to follow the philosophy of permaculture: that is to say: no pesticides, herbicides, nor artificial fertilizers. The soil is not cultivated and is protected the whole year round by a thick mulch layer  of straw and hay. Last year I installed an exudation irrigation system  because it seemed that a layer of 20 cm straw was not sufficient to cope with the tremendous drought of the last summers.   

Last but not least I can comment that the house is heated by a woodstove, the wood coming from the pruning and cutting of the trees on the terrain of course. Running water is provided by the local village.

Of course this story is far from complete and there are many topics not mentioned. For those who are interested in more details I can recommend my personal weblog where I intended to reflect the whole and ongoing process of building the house and managing the terrain.

Just type natureswitchedon in Gogle or in Spanish lanaturalezaactivada to get almost directly to my weblog, in two languages by the way.


This is it so far. Thanks for your attention. I am happy to respond to all of your questions and comments.

Andreas Brons, February 2017