It is hard to believe but we are already in our seventh week in Tanzania!
We started the week with the mix for the cob. In order the prepare the soil to be mixed with the sand, we made two big holes in the ground and filled them with water. The soil must stay inside the pool for at least 24 hours before the mixture is done.
We continued building the rammed earth wall and solving all the problems we found on the way. The main difficulty has been to keep the side walls fixed. With the force of the tamping they tend to separate and therefore the corners become weaker.
The next day we prepare the mix for the cob with soil, sand and banana leaves. After mixing, we make small and dense mud balls that are carefully placed in the wall. It is a slow process but after a few days we can see the first results.
The height of the rammed earth wall finally goes up to the height of the window and we can remove the formwork and prepare it for the next piece of wall!
Working on the improvement of the side walls of the formwork.Primli applying a layer of lime after the first rammed earth section of the wall.Jule and Clémentine tamping the earth wall.Jule dancing on the mixture to compress.Mixing the soil, sand and banana fibers.Priscus the carpenter working on the construction of the windows.Clémentine has become a “fundi” (suajili word for expert) of molding the cob wall.Children helping to shape the cob balls.Tomás and Michelle tamping the last section of the wall, finally!Moving the formwork and placing the carpentry to start the next wall.
The week started with the visit of Mashambo, the district engineer, to check the development of the project and give us advice. Together we checked the different tests for both rammed earth and cob and we decided which earth mixture was the most suitable. The best options for rammed earth were either 40% soil + 60% sand or 45% soil + 45% sand with small cement stabilization. For the cob the suggestion given by the engineer was to add some more banana fibers to give the mixture more strength. He congratulated us for the advances with the earth work and he explained us his aim to implement earth building techniques in his hometown!
The construction of the gabions has been completed. The last step before bringing them to site was painting the metal net with anti-oxide, which turned its color to red. Afterwards, the 12 gabions were placed on site and filled up with stones.
We have continued with the over foundations of the verandah, that have been built following the same procedure than for the rest of the over foundation, but with a total height of 30 cm and leaving a hole where the junction with the wooden pillars will come.
We keep on digging! The hole from where we obtain the soil is getting bigger and bigger. We have started to prepare earth mixtures following the proportions of 45% soil + 40% sand + 5% cement + 10% water, although cement and water will not be added until we are completely ready to pour the mixture. The preparations for cob have mainly consisted on collecting and peeling the banana tree fibers, in order to get thin and long fibers that will reinforce the earth mixture.
We have cut the wooden pieces for the formwork and the frames that will support it and we have ordered and picked up the first wooden window, to be used as one of the sidewalls of the formwork. Once the first formwork was finished, we took it to the site and placed it fixing it to the wooden frames using metal rods. The first layer of earth mixture was poured into the formwork and was tamped until its height decreased from 15cm to 8cm. We have successfully achieved to build the first section of rammed earth! After a couple of days we removed the formwork and we had to shape the side faces because the formworks sidewalls had slightly moved with the strong tamping movement.
We have also been testing and developing some possibilities of recycled furniture; getting old tires and turning them into seats for the library.
The week ended with a trip to Kalasia waterfalls in Marangu, where we enjoyed taking a short bath, having a picnic and walking around the nice forest. Before arriving we stopped on the road to buy some baskets and collect some information about its fabrication, because we would like to include the pattern as enclosure in the library. On the way back we stopped in Mamba, where the produce and sell speers. The day ended up at Mr.Matolis house in Kibaoni, where we were invited to banana beer.
Checking the rammed earth tests with the engineerPablo, Patricia and Mashambo comparing the different cob tests
Paloma and Alberto painting the metal net to avoid rustingThe gabions are getting filled up with stonesDividing tasks and working in the garden: cob, formwork and furnitureNailing together the pieces of formworkMore diggingPlacing the frames and fixing them with metal rodsTamara tamp! Pablo tamp!Capres shaping the side of the rammed earth wall with the macheteBaskets are sold on the road to MaranguJule and Kilasia waterfall
Because of the light slope, and in order to protect the building from water and to contain the earth during rainy season we have started designing and building some gabions; boxes made out of metal net and filled up with stones. We bought metal net and we decided what the best sizes were in order to optimize the material as much as possible. We tested different ways to join the faces of the gabion with metal wire. For several days we have being digging behind the building to leave an appropriate distance between the gabions and the backside wall of the library.
The lack of water in Kibaoni Primary School has brought some difficulties to build during these last few days. Nevertheless Anatoli and Primli have finished building the over foundations with stones and concrete, pouring a final layer of concrete to level it and leave it prepared to start with the earth walls. We have compressed the earth between the over foundations and we have started filling it with stones. Although at the beginning it seemed that we could just randomly throw the stones inside, the work is not that easy and it needs to be done carefully, placing the stones with order and creating a surface with the same level.
We have continued with the rammed earth tests, making bigger samples of those mixtures that seemed to be the best. We have also tested other techniques like cob and adobe. For cob, earth, sand and straw are mixed together in balls, creating thick load-bearing walls. We have done the final drawing for the rammed earth formwork and bought the necessary materials to build it.
Since we will need a lot of earth to build the walls, we have started digging a big hole next to the project site. The first meter of earth is not appropriate because of vegetation materials and crops- mainly potatoes and beans- which turn the soil too silty. Therefore the first layer of soil has been removed and all the soil beneath is being piled up to be used in the future weeks.
Cristina and Sofía building gabionsThe school´s tank is almost empty and water needs to be pulled out as if it was a dwellAnatoli and Primli building the over foundationsAlberto compressing the earth like a circus manForming a chain to move the stonesJule carefully placing the stones like a real “fundi”(expert in suahili)The whole area has been covered with stones. Afterwards it will come gravel and soilTesting cob technique using hands and feetDancing on the cob mixture to compress itThe big team having lunch outsideTomás, Jaime and Pablo digging with full power
On Monday of our fourth week in Kibaoni we continued placing the stones in the foundations and pouring the last layer of concrete.
The next step was to start putting strings to mark the path for the over foundations and we built some wooden sticks to mark the width of 40cm all along the foundations.
On Friday we were invited by Mr. Matoli to a celebration for Saint Ignacio de Loyola. It took place in the house of a neighbour and, as usual, it consisted on a mess and afterwards, a big amount of delicious food was served. After, we enjoyed dancing with all the kids until we were exhausted and came back home.
This week we also began testing the earth to gain knowledge of the soil’s consistency at and around the construction site. Our aim is to find the best mixture of earth, sand and fibers. Therefore we made a small, wooden 20×20 cm large formwork for testing blocks.
Firstly, we started making test block of rammed earth with the earth from the construction site and water. The block started to crack after an hour, though after it dried, its pieces were hard. The contractive nature of clay in this test made us believe that the top layer of the sediment tests was clay. We then performed several experiments with different proportions of earth and sand mixed with water. The mixture of 60% sand and 40% earth seemed the most resistant. We rammed 13cm of airy mixture into 8cm. We made the tampers from wood, cement and concrete.
We then did several tests with cement up to 15%, and additives like pig and cow manures from the neighbor’s farm, and salt, to revitalize the soil since the site was a monoculture of potatoes. We rammed many differenttest blocks from superdry to very wet mixtures: some with cement or fibres.
While digging on the site, we discovered a new type of earth, reddish, rich in iron, that seemed to have clay. We continued the tests with this new soil.
After some days testing for rammed earth, we also started experimenting new techniques in earth construction inspired of local architecture: Cob and Adobe. Tests seem to show that a ratio of 1:1:1, earth: sand: fibres, and relative damp material gets us the best result for these techniques. Also, the rammed earth tests showed that a mixture of 80% sand and 20% earth without additions and a wet texture is the best yet! It is similar to the Shuttered Cob technique in Britain in the 19th century. But let’s see what the next week will bring!
Entrance of Kibaoni from the road.Primly placing the strings for the over foundations.Non-sense situations on the working site. This time a seller trying to sell fancy Tanzanian pictures to us.Lara, Cristina, Inés, Sofía and Jule discussing the design.People digging. This time we counted on the help of some girls from Secondary School.Anatoli and Primly placing stones for the over foundations.Afternoon audience after school time.Cristina, Inés and Sofía helping the cookers to prepare dinner.A view of our beautiful acacia with a kid climbed on it. The favourite view spot for many children of the school.Pablo and Rubén placing the small formwork for earth tests.Analyzing the results of the earth tests.Some tests worked very well but some others were too weak and broke after a few hours.
Our third week in Kibaoni started with a visit to the near city of Moshi. We had arranged a meeting with C-re-a.i.d., a young association of architects mainly from Belgium that has been working in Tanzania since a few years.
We shared thoughts and knowledge about earth and social architecture and after the meeting they brought us to a beautiful spot to wait for the sunset. It was an old abandoned train station in Moshi.
After spending the day in the noisy and crowded Moshi we were happy to come back to the beautiful Kibaoni, a place that we already feel as home.
On Tuesday we started with a meeting at home to discuss about the design of the sieve, formwork and other things in order to buy all necessary materials to build them.
With the help of a local mason and a local carpenter, we were able to finally start pouring the first layer of concrete and place the formwork in those places where the foundation walls were not stable enough. Afterwards, we placed the stones mixed with earth and the oncrete up to ground level and let it dry. For the masonry, we counted on the great support of Anatoli and Primli, two local labourers that have joined our team lately.
In the meanwhile, we had taken some samples of soil from the fields around the site to make some tests that could give us an idea of the quality of the earth we had. We firstly made some basic field tests to see its composition and strength. As the result was not clear enough to let us know if the soil was suitable for construction, we built a small formwork to make small rammed earth walls and see what would happen after letting them dry. We mixed different percentages of earth from the site, sand and even a small quantity of cement.
Not everything in Kibaoni is work. On Wednesday we were invited to an engagement ceremony and we had the opportunity to see how a Tanzanian celebration is and all its rituals and fancy decoration. As usual, we felt warmly welcome and enjoyed the evening very much.
Moshi´s old train station, a beautiful spot to watch the sunset.Meeting at home to discuss about the design.“Jason the local mason” helps us to mix the concrete.The first layer of concrete is poured all along the foundations.It is not so easy to keep enough water on the site with so many thirsty little people around!Paula, Pablo, Nacho and Elia´s hands behind the formwork.After placing the stones, they are covered with soil and eventually with a layer of concrete.Once the last layer of concrete is poured, we must wait until it is dry to continue with the second part of the foundations.We visited a sawmill nearby to buy the wood we need for pilars, trusses and other elements.Some participants building a sieve to filter the sand.Sedimentation tests to see the quality of the soil.We were invited this week to the engagement ceremony of a neighboring family of the village.We are working very hard, but we are also having an amazing time.
We went to Moshi to visit the work from Shift Design, who are building a dining room next to Magereza Primary School. The building is made out of compressed earth blocks, with the use of bamboo to reinforce the structure. They gave us very useful tips and recommendations. We wish them all the best for their last weeks before they return back to New Zealand.
We started the works! The first steps in the construction process were to clear the site, level it and compact it. To mark out the walls and foundations a grid was created using string nailed to wood sticks as guide. Afterwards and for the next few days we dag the foundations until we reached hard soil.
We have received trucks of stones and sand to start building the foundations as soon as possible!
Our bohemian neighbour from Congo came home with his guitar and we had a nice evening together.
On Sunday morning we joined our friend Samweli at Kasirwa´s church, where we were delighted by their nice singings and their hospitality. The mass ended up with an auction where we received different vegetables as present.
Dining room by Shift DesignTogether with Shift Design TeamTaking measures of the site to start with the worksCleaning the siteNacho and Samweli digging the foundationsOur loyal audience always watching the construction processLea taking a nap under the banana trees after a hard day of workMore diggingFirst truck of stones arrived but they were far too bigMidday break and the cows visitLara, Jose and the white little calfInside of Kasirwa Evangelical Lutheran ChurchAuction after the mess
We arrived in Tanzania! From Kilimanjaro International Airport we travelled to Kibaoni village, where we will be staying for the following 3 months to build the community library. Kibaoni was welcomed us with opened arms!
First participants have arrived and Mr. Matoli, Kibaoni´s friendly Chairman, has showed us the village and its sorroundings. We have been in Kasirwa visiting previous works from Orbe Design Studio and buying some vegetables from local gardens. Kibaoni and Kasirwa´s local architecture has surprised us for the use of local materials such as earth, wood, banana leafs, etc.
We have visited the site where the project will be located, next to Kibaoni Primary School. Talking with the teachers and the engineers we decided the best location and orientation for the building.
The team is getting bigger The courtyard of our house, full of corncobs freshly peeled Construction from Orbe Design Studio in KasirwaMama cutting the biggest cabbages from local garden in KasirwaHouse in KasirwaStorage room in Kibaoni made out of wickerKibaoni Primary School
We need your help to raise the necessary funds to carry out the construction of the earth community library in Kibaoni, Tanzania. We find ourselves now in the final stretch before the project starts and we need your help to make it possible!
100% of the money collected will go towards the completion of the project, buy materials and hire local labor.
Let’s raise the almost final 2500 Euros together before we start with the construction!
Please spread the word and donate what you can! Every contribution will be appreciated!
– If you donate 20€ or more we will send you a short film documenting the building process, which will reflect exactly what your contribution has made possible!
– If you donate 100€ or more your name will be written in one of the walls of the library, together with the rest of local workers who helped us to build it.
Thank you so much, or as they say in Tanzania: ASANTE!
We want to share with all of you the drawings we made in our interest to continue developing and exploring the earth techniques we want to use in Tanzania. We adapted the earth prototype we submitted for the competition to respond to the new program; the library.
The configuration of the plan allows the existence of spaces with different level of privacy and combines the use of thick solid rammed earth walls with lightweight claddings that can be kept closed to preserve privacy or widely open, which also allows cross ventilation throughout the building.
The most enclosed room is conceived as a multifunctional space to carry out different activities such us lectures, meetings, classes… The semi-enclosed room is conceived as a lecture room, together with the courtyard. The backwall is reserved for water harvesting.
Sustainable design principles are at the heart of the architectural approach. The main material used is rammed earth, following the traditional method of construction. A zinc-roof is designed for optimum natural ventilation, and to collect rainwater for treatment and reuse. Timber is used for roof trusses and pilars and the whole building is elevated over a plin made of rocks collected from the surrounding area.
Geometric rills cut into the earth walls during construction introduce light and ventilation as allow saving costs in frames; its treatment throughout varies in depth, width and height result in different levels of privacy and therefore define uses for different parts of the house.
In this way, we can find holes used as windows, but also others used as shelves to store books, seats or folded tables.
Taken overall, our mud house might be regarded as a mini manifesto for earth architecture, not just in Kibaoni but in other parts of the country too. Contrary to the abuse of concrete as a building material, that raises the cost and therefore the poverty of so many expanding communities, it shows how new earthen buildings can be inserted into the existing frame at increased densities, while sustaining traditional building techniques and preserving the natural environment.
Tanzania Goes Mud! 