I made a comment on Facebook recently stating how much I love to work with cob more than any other earth building method.
Here’s a selection of techniques and my impressions which help me decide which method to use in a specific location:
We’ve built Earthbag foundations in Canada (OUR Ecovillage ), Tanzania and Cameroon. The earthbag foundations work well and are low cost in places where stone isn’t available.
At a Natural building colloquium I filled long tubes with earth. Friends from the natural building movement have built beautiful domes and other homes with this method. I believe if there’s clay in your soil, forget the bags and build freely with that clay-soil. It’s a matter of location and what’s available.
Another amazing technique producing beautiful and stunning buildings is Rammed Earth. Layers of different colors tell the story of the earth at the location. I’m talking about rammed earth free of cement here, as its being done by several builders in Europe. This way of building requires serious formwork and planning. My personal experience is limited to observation, because in my work I’ve been in locations where that formwork is very difficult (expensive) to build. As a result rammed earth shows up on the high end of building cost and in larger scale buildings.
Many cultures have built with Mud blocks (Adobe) and still do so. Here in Cameroon I see homes being constructed with a mud-block infill system, using concrete for structural support: ringbeams and to bridge large openings. Local people have experience producing these blocks and will make their own when it’s time to build a home. Making blocks doesn’t require much: water and clay-soil. Fiber isn’t so commonly used but is useful to prevent cracks and to strengthen the blocks. You need a flat area to lay out the blocks to dry in the sun- this will take about a week. Then dry storage until construction begins. Building walls with blocks requires some skill- to build a house takes some practice at masonry work. And those blocks are very heavy to lift. However, depending on seasonal patterns and workflow, this can be a great way to build an earth home.
Compressed Earth Blocks
Compressed earth blocks (CEB’s) can be made with or without cement for stabilization in various shapes and sizes. Simple mechanical block presses require at least two people to work together – mixing the clay-soil (sometimes sifted) with a little water, then filling the form and compressing with the power of a long lever. Scale it up and you’ll see machines working with hydraulics taking the hard work out, but driving up the cost . The result is a firm, even block, sometimes interlocking. We’ve just finished building our dormitory walls with CEB’s – because we had the perfect soil on site, were too late in the season for sundried blocks , and had straight walls to build. We hired a local builder to lay the blocks as they came from the press. It got the job done.
Parallel to this process our volunteers were building with cob. We created some hybrid walls with the blocks to add sculptural details and bottles. And we shaped benches and a lounge area. A layer of cob fills awkward spots in the block walls (filling around posts etc) . I watched inexperienced building volunteers mix great batches of cob, build the walls and trim them. Everybody took on designing with bottles- allowing one individual to be the overall artistic eye.
And that’s where that statement came from.
Watching people, who have never built anything, confidently building something beautiful makes my heart sing.
We’ll be moving into Earth plasters next – where sculptures get refined and block-walls disappear behind a hand-applied layer of mud. Earthen plasters can be simple sand/clay mixes applied by hand or more sophisticated ones with additions of ingredients like mica or marble dust, finished with special trowels. It’s up to the availability of materials, skills and taste, desires and budget of the owner.
Hybrid of techniques
The beauty with all of the options above is the possibility of mixing things up. We call it hybrid homes- for example walls of cob on one side and straw-bale on the other. Or adobe with inserts of cob for bottles and other sculpted elements. All tied together with beautiful natural plaster finishes.
I’m heading to Kenya this summer to create a cabin for my host Joannah in a couple of workshops. She’s already collecting beautiful things to incorporate. Dreaming her space. Clearing the site.
When participants arrive we’ll work with a selection of techniques appropriate to the location and learn about decision-making in the process. This opens up the possibility of being creative builders in collaboration with others. We’ll be supporting the first stage of a learning center for permaculture in a protected forest.
So if you are so inclined, come to Kenya this August! You will get your hands muddy and experience a different sort of safari!
Going for a walk recently we came upon this old house. I’m always curious when I see clay-infill or earthen plasters, so the exposed bits of earth caught my interest right away.
I’ve learned a bit about the local historical buildings too and could tell that this was what they call “Umgebindehaus”, where on the ground floor you see wooden posts and beams in the face of the wall behind which lies the livingroom (Stube) made of heavy wooden slabs that are covered on the outside by earth. The upper story is built on top of the post and beam structure, in local Timberframe (Fachwerk) style, also with earthen infill.
The owner’s dog was alerted by our looking at the front corner, which in turn alerted the young woman living in the new building behind the old house. She called out “Are you interested?” And when I explained my curiosity she invited us in to have a closer look.
“We’re trying to give it away”, she said, “it’s under protection as heritage building (Dekmalschutz), so we can’t tear it down. “
There had been interested parties – someone wanted to take out the “Bohlenstube” –the wooden livingroom- but then decided against it.
“You can take away the upstairs pieces and rebuild it somewhere else” she went on.
Upstairs we noticed that this building is seriously threatened: the roof is leaking in one place and on the other side the wall is open and the earth is getting wet and falling onto the floor. Nobody is fixing it- instead a new building was built behind for the family to live in.
Sadly, this is not an isolated case: in this region rich with historic buildings, there are many in poor repair. Owners of heritage buildings must negotiate any changes with the department for heritage buildings. Unfortunately this often blocks good ideas, and discourages good intentions in the name of protection.
But when people can’t make changes (to increase ceiling height, create more windows, add pieces) then these building get left to break down and rot. And so they stand witness not to the beauty of former building skills but to a lack of positive cooperation on the part of those that are supposed to be their protectors.
One outcome of this conflict of interests is a very low market value of heritage homes.
In the case of the one we looked at: take it away for 1 Euro.
Should you be interested in contacting the owners, please email me
Today I am pleased to share some pictures with you. We have finished our building in Mnenia and it is ready to be occupied. I found it difficult to take adequate pictures: the house is small but feels spacious. Photographs can’t give you the feeling of the light breeze, the sound of the birds, or the cool inside on a hot day. We very much enjoyed staying in the house and hope to return.
In the beginning of the project we set out to build with mostly local materials. I can now say that the stones, sand, clay, bricks and sticks all came from within 1 km of the building site. We hired people to make door and windows in Kondoa, the closest town. Cement and Lime were produced in Tanzania, near Moshi. The many hands that helped were also mostly from the village, except our dome ‘fundi’ Petro Omala, Goodluck Omala, and a few short term volunteers.
Have a look and let me know your thoughts!
I have dreamt of going to Morocco ever since I was a teenager in Germany, when it was still one of the destinations on the Interail train-pass. Marrakech was one of those names for me that carry mystery and calling. What better time to go than during this trip on Sabbatical.
Even today, where travel is easy and things we value, like safe drinking water, are readily available everywhere I’ve been, the sensual impact of a Moroccan town is big. Colours, smells, sounds and the mazes of old buildings and markets are at times overwhelming, but mostly awe-inspiring to me: I am definitely in a different culture!
The Arabic world is rich with ornament: from jewelry to buildings, in metal, plaster, thread, wood and leather. Patterns and symbols carrying meaning and story are passed on from generation to generation. Craftsmen and women spend their lives working on fine details, often using methods unchanged over generations.
And yet: the modern global flavour is strongly influencing local tastes: everywhere, but perhaps more in urban areas, we saw a blend of worlds: traditional gowns, tight jeans, Moroccan leather slippers and western style knee-high boots. Cellphones are everywhere.
The old world of the Medinas is full of the richness of tile work and plasters. Visiting the Ryad Moqri in Fez, which is now housing a school for the traditional crafts, I learned a little about the technique of the fine plasterwork. The pattern is transferred from a cast using a powder-coating. Then the plaster is cut to the depth desired by the artisan. The result is a relief with strong shadows.
Old buildings require repair and I saw plenty of restoration underway. Newly plastered facades grace beautifully restored interiors. Modern materials replace older tools here too: a plastic burnishing tool.
The sense for decor doesn’t stop in old town: high end condominiums also show attention to detail and seem to carry the traditions forward adding modern style.
Tadelakt plasters are a lime finish that we have just recently been learning about in Canada; Morocco is where this technique originates. We saw beautiful examples both indoors and out. They set the mood of a place and give elegance and beauty featuring cut out patterns and bright colours.
The waterproof surface isn’t used just for wet environments: here restaurant walls, hotel foyers and courtyard walls are finished with shiny blue, red and yellow. You can even take some home in the form of small containers bright turquoise, blue, pink or purple.
As a designer and builder of earthen homes I appreciate the work of finishes as much as the construction of the building.
On a trip south into the desert we saw towns and villages of earthen architecture; some dating back hundreds of years and kept in use or restored, others crumbling and in disrepair. There are themes in the architectural form: corner towers, stepped rooflines, courtyards and large colourful gates.
Houses are built tight together three or four stories high. Narrow streets and walkways are bridged here and there by arches of stone. The old buildings are built of mud bricks or rammed earth on stone foundations, tapered on the corners. They are covered with earthen plaster that is rich with straw fibre. Cut patterns create sharp shadow lines . The colour is the colour of the earth around, ranging from red to orange and yellow tones.
The desert climate allows for clay roofs as well. Layers of bamboo and clay over wooden beams form terraces that blend completely into the landscape.
It’s not all good though; earthen buildings need to be maintained annually and slowly fall apart if not cared for. They do age gracefully and damage can be fixed- even by re-using the original materials. It takes time, interest and energy to make that happen and out in this desert new buildings are often built with cement blocks like everywhere else. In comparison they appear sharper, their colours less attractive and clearly artificial. And if you’ve ever felt the difference inside when it’s 40 degrees outside you’ll stay with the mud.
I was often reminded of villages in Northern Sudan that I saw a few years ago: the private sphere of the courtyard behind walls of earth, bright coloured gates and large clay water urns on the roadside. A gesture of hospitality – even at the gas station.
Interesting linksHere are some interesting links for you! Enjoy your stay :)
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