Association La Voute Nubienne

Association La Voute Nubienne

Earth roofs in the SahelA Case Study

January 2009

AVN-Burkina Faso local centre in Boromo

Association la Voute Nubienne (AVN) : the 'Earth roofs in the Sahel' Programme

Contents

1 The Association

2 The Project Context

3 Partners and Sponsors 3.1 Early Partners 3.2 Field Partners in Burkina Faso 3.3 Field partners in Mali 3.4 Field partners in Senegal 3.5 Individual Sponsorship 3.6 Institutional Sponsors

4 Project Description 4.1 Main purpose 4.2 Summary of the VN technique - A single-storey house - A two-storey house 4.3 Main beneficiaries 4.4 Current stage and future plans 4.5 Project costs and funding 4.6 Social aspects 4.7 Environmental aspects 4.8 Economic aspects

5 Barriers Encountered

6 Lessons Learned

7 Innovation and Impact 7.1 Key innovative features 7.2 Indicators of success and impact 7.3 Monitoring and evaluation

8 Recognition

9 Transfer

10 Two AVN 'champions'

Annex: VN Building Guidelines

AVN International

9 rue des Arts, 34190 Ganges, France

Program Director: Thomas Granier [email protected]

Mobile 00 33 (0)6 17 04 08 33Tel 00 33 (0)4 67 81 21 05

Development Director: Antoine Horellou [email protected]

Mobile 00 33 (0)6 98 21 70 00Tel 00 33 (0)2 98 43 31 63

Anglophone Contact: Tony Kaye [email protected]

Tel (France) 00 33 (0)4 67 73 30 91Tel (UK) 00 44 (0)1908 262 459

USA / Canada Contact: Julia Brooke [email protected]

AVN Burkina FasoSecteur 1, BP 505, Boromo

Programme Coordinator: Séri YoulouTel 00 226 20 53 81 84

Mobile 00 226 76 64 37 64

In Ouagadougou: Zalissa [email protected]

Tel 00 226 50 34 57 42Mobile 00 226 70 32 89 34

AVN Mali

Programme Coordinator : Mathieu [email protected]

For more information and VN news:

www.lavoutenubienne.org

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mailto:[email protected]

http://www.lavoutenubienne.org/spip.php?page=sommaire&lang=en







The Association

The Association la Voute Nubienne (AVN) is an NGO registered in France and in Burkina Faso; it was founded in the year 2000 to promote the construction of vaulted earth brick houses which are environmentally friendly, sustainable, affordable, and comfortable, using a now well-proven technique: la Voute Nubienne (VN).

The VN technique, a simplified, standardised, adaptation of an age-old technique from the Nubian region of Egypt, is relatively unknown in the Sahel and West Africa. This simplified technique - an exemplar of South > South technology transfer. - has been validated at the technical and socio-economic levels during the first few years of AVN's activity and is now in a phase of development and scaling up.

Now, through its 'Earth roofs in the Sahel' Programme, the AVN organises the recruitment and on-the-job training of VN builders in the Sahel, helps them to become independent VN entrepreneurs, and provides a developing pool of clients for them through its promotional, communication, and networking activities.

Key beneficiaries of this project are rural families who acquire VN homes, local builders and apprentices working for the programme who become independent VN artisans and entrepreneurs, and the associated workers (earth brick makers, transporters, labourers). Scarce funds previously used for buying imported roofing materials stay in, and stimulate, the local economy.

Achievements

Over the last eight years, the 'Earth roofs in the Sahel' Programme has seen an average annual growth rate of 70% in the numbers of vaults built and VN masons trained.

By June 2008:550 vaults built, mainly for family homes

115 VN masons trained170 apprentices in training

3000 months of wages generated7,600 direct beneficiaries

The AVN Programme, which started in the small town of Boromo, in central Burkina Faso, has spread to many parts of the country, and beyond, with trained VN builders in Mali, Senegal, Togo, Ivory Coast. and Guinea.

Origins

In the Spring of 1998, a Burkinabé farmer (Séri Youlou), and a French builder (Thomas Granier), erected two prototype vaulted buildings from earth bricks and earth mortar, without using any timber either for shuttering or in the structure of the buildings. The following year, with some technical advice from Acroterre (the School of Architecture, Grenoble), and the help of local people, two larger buildings were constructed, showing that the technique could be popularised and adapted. It was this promising start which led, two years later, to the founding of AVN as a logistical support base for the 'Earth roofs in the Sahel ' Programme, a programme which the first corps of trained Burkinabé VN builders has helped to spread from Burkina Faso to several neighbouring countries of the Sahel..

Organisational Structure

AVN International is registered in France and regulated under the terms and conditions of the Law on Associations of 1901, with a President (co-founder Thomas Granier), a nine member management committee of volunteers, and a salaried Development Director. The Association holds regular Assemblées Générales to decide on ongoing issues and strategies,.and to oversee AVN's fund-raising, communication (website, brochures...), and development work. A significant amount of time is devoted to handling requests for field partnerships and for new construction projects in Burkina Faso and neighbouring countries, and in preparing training and information materials for VN masons and clients.

AVN Burkina Faso, with four salaried local staff under the leadership of AVN co-founder Séri Youlou, is based in Boromo, with a small office in Ouagadougou. It is responsible for recruiting new apprentices, overseeing their training, putting eventual clients in touch with local VN builders, and monitoring the AVN Programme. Given the increasing demand for VN constructions in neighbouring countries, plans are currently underway for setting up similar structures in Mali and Senegal.

AVN has representatives in Italy, Spain, the UK, and the USA to handle queries and help in fund-raising at national levels in these countries.

Several internships for post-graduate students of architecture, economics, and development studies have contributed significantly to AVN's Programme over the last two years.

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2 The Project ContextThe Sahel region of sub-Saharan Africa extends from the Atlantic in the west to the Red Sea in the east, in a belt varying from several hundred to a thousand km in width, covering an area of 3,053,200 square km. It is a transitional region of semi-arid grasslands, savanna, and thorn shrublands lying between the wooded savanna to the south and the Sahara to the north. Countries wholly or partly in the Sahel include Senegal, Mauritania, Guinea, Mali, Burkina Faso, Niger, Ivory Coast, Ghana, Togo, Nigeria, Chad, Sudan, and Eritrea.

The estimated population of the Sahel is of the order of 150 million, of whom nearly half are surviving at a bare subsistence level. It is estimated that over one-third of the population are unable to afford essential medicaments and vaccines, and, for a similar proportion, access to ready supplies of safe drinking water is problematic.

Housing conditions for the majority of the rural and peri-urban population of the Sahel are not good.

Traditionally, sedentary families in the region (as

opposed to the nomadic groups) build their homes with dried earth brick walls, supporting roofs incorporating bush timber. In some cases, the roofs are sloping (or conical) and thatched - something like 20% of families live in village houses of this type.

More substantial houses have solid timber and earth roofs, with beams and rafters supporting laths dressed with an earth mortar, on top of which a flat terrace roof is constructed using earth bricks, with a final rendering of earth mortar mixed with a waterproofing adjuvant. The adobe / earth brick walls will often incorporate load-bearing timber posts. Around 10% of houses are of this type of construction.

However, population growth in recent times, together with increasing desertification and regression of forested areas, means that these traditional building techniques are no longer feasible. And in regions

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where some tree cover is still left, use of bush timber for construction is either illegal, or requires purchase of expensive permits.

As a result, for many years now, families in rural and urban areas have had to resort to buying sheet metal (corrugated iron) and sawn timber beams and rafters for roof-building.

Sheet metal roofs have many serious disadvantages, especially the poor thermal and sound insulation, making houses too hot in the day, too cold at night at certain times of the year, and extremely noisy during the short but intensive Sahelian rainy season. They are also relatively fragile, can easily be damaged by wind and rain if not properly fixed, and may even be at risk of theft. The average life of sheet metal roofsf is only around ten years, as a result of rusting and corrosion. And they cannot, of course, support a traditional flat terrace roof.

Such imported building materials are often beyond the means of many people. They have to be paid for in cash, often a problem for those living outside any formal economic system (some families may spend five years accumulating roofing sheets one at a time when they can afford to buy them, before eventually being able to construct the roof). Finding the necessary funds for these materials becomes a major drain on family resources; however, around two-thirds of Sahelian families are living in houses with costly sheet metal roofs, supported by earth

brick or cement block walls.

A house built using the VN technique, in contrast to one with a sheet metal roof, is more comfortable, healthier, and more robust; it can be built with readily available local materials and labour, keeping scarce monetary resources in the local economy. Externally, the vault can be 'topped out' if required to form a traditional flat terrace roof, useful for drying crops, and laundry, for storage, and for extra habitable space. A VN house can easily be extended and modified as resources become available and families grow.

The originality of the VN approach lies in the simplification, codification, and modularisation of the original technique, and the reliance on training new masons rapidly through on-the-job apprenticeships on actual VN building sites.

Interior and exterior views of a VN home

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3 Partners and Sponsors

3.1 Early partners

In the early design and planning stages of the AVN Programme, technical support was provided by Acroterre (University of Grenoble School of Architecture), with financial backing from the French Ministry of Foreign Affairs over a three-year period (2003 - 2005). During this period, as a result of contacts made between the Mayor of Grenoble and his team, and the mayor of Ouagadougou and the directors of the SIAO (Salon International de l'Artisanat de Ougadougou), a two-vault show house was built for the Salon to demonstrate AVN’s vision of an alternative architecture for the Sahel.

3.2 Field partners in Burkina Faso

Most VN buildings resulting from field partnerships so far have been for community use, but they serve as excellent demonstrations of the VN technique as a valid alternative for housing amongst the local communities they serve.

The Catholic Community of the zone of Petit Balé, with financial support from friends in France, has built a superb triple-vault church in Petit Balé; this was the first VN building to us reinforced concrete beams and pillars to support the vaults, making a wide open space of >10 m width.

The Association Zoramb Naagtaaba-AZN represents a group of 7 villages in the zone of Guié in an agricultural development and health project. The Association has constructed several VN buildings, and is actively participating in the promotion of the AVN programme.

Arquitectos Sin Fronteras en Bobo, region of Bobo-Dioulasso The Italian architect Chiara Rigotti has helped design the first schoolrooms using the combined VN-RC (reinforced concrete) method, in the villages of Ouara and Samandéni.

L'Association de jumelage Dano-Etrechy The twin-town Association of Dano-Etrechy has constructed several VN buildings, and is promoting the VN programme in the region of Dano as an integral part of its professional training work.

L’Association de jumelage Bagassi-Lisieu This twin-town association has constructed several VN buildings, and is considering its further involvement in the VN programme.

Several new partnerships are under negotiation for the next few years. AVN asks NGO's and Associations whose funding comes from sponsors in Europe to make a voluntary contribution of 20% of gross construction costs to AVN to help finance recruitment and training of future VN apprentices.

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http://asfbobo.blogspot.com/search?q=AVN


3.3 Field partners in Mali

The Africabougou Association (Italy) : the Italian architect Emilio Caravatti has designed a school, a teacher’s house, and a dispensary around Kati, using the VN-RC technique (Reinforced Concrete beams and pillars, first used for the church in Petit Balé); future VN buildings are being decided on the basis of a survey amongst the local population.

The Tapama Association (France): this Franco-Malian Association, has built a VN house in the village of Nafadji, and plans further developments.

Intervida (Spain): this NGO has signed an agreement with AVN for building in and around Segou.

AIADD-Solidarité (France) has built a dispensary and maternity clinic using the VN technique in the quartier Pelengana of Ségou; a partnership agreement with AVN for further projects is being drawn up.

3.4 Field partners in Senegal

Mozdahir International Institute: the first VN buildings in Senegal have been constructed for this Institute, in the Tambacounda zone of the Casamance, and a partnership agreement for further work - including

the construction of an entire village- is currently being drawn up.

La Communauté de Communes du Val de Drome will be supporting the AVN Programme financially, and employing VN builders to train local masons in 2009/10 on construction sites in the region of Matam.

Further VN development in Senegal is being carried out under a franchise agreement with a Senegalese builder based in Dakar.

3.5 Individual sponsorship

AVN currently receives over 1,000 Euros/month in regular monthly donations from private individuals, mainly in France.

GlobalGiving : a s a result of being chosen as a a laureate for a Tech Award in 2007, AVN features on this ’online marketplace’ for aid projects, enabling prospective donors to find and contribute directly to the AVN's Programme.

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3.6 Institutional sponsors Ashoka France: AVN receives valuable strategic and development support through the Entrepreunariat social et Innovation Programme. La Fondation d’entreprise Veolia has provided major financial support for the AVN Programme in 2007 and 2008.

L’Association SolidarCité , part of the French PPR Group, made an award to AVN in its ’Social Entrepreneurs 2007’ competition.

Groupe CFAO : through the contribution of its CEO, Alain Viry, is helping AVN with its experience and network of contacts in West Africa.

La Fondation Hermes has recently confirmed a major sponsorship agreement with AVN for 2009 and 2010.

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http://www.cfaogroup.com/?&langused=uk

http://www.cfaogroup.com/?&langused=uk

http://en.wikipedia.org/wiki/PPR_%5C(company%5C)

http://en.wikipedia.org/wiki/PPR_%5C(company%5C)

http://www.solidarcite.org/

http://www.solidarcite.org/

http://www.fondation.veolia.com/fr/

http://www.globalgiving.com/

http://www.globalgiving.com/

http://www.africabougou.org/progetti.php?pr=4




4 Project Description

4.1 Main purpose

The main purpose of the AVN 'Earth roofs in the Sahel' Programme is to promote the construction of vaulted earth brick houses which are environmentally friendly, sustainable, affordable, and comfortable, using a now well-proven technique: la Voute Nubienne (VN). Such houses can be built with readily available local materials and labour, keeping scarce monetary resources in the local economy, and promoting economic development. AVN is helping in the development of a fast-growing and self-sustaining market in VN housing through its training, communication, support, and development work.

4.2 Summary of the VN technique

The special features of the VN technique:

(1) During construction, a guide cable, stretched between the two gable walls at the height of the base of the vault, defines the central axis of the vault; a cord fixed to a sliding ring on the cable acts as a guide to ensure a constant radius. Towards the top, the mason adds a couple of fingers width to each joint to develop an ogival (catenary) shape.

(2) The roof is water-proofed, using locally manufactured plastic sheeting over a smooth coat of mud mortar. The plastic is covered with a 5cm rendering of enriched mud mortar, protecting it from damage by the sun, and providing additional protection against heavy rains. It also acts as a warning signal: if the (black) plastic sheeting is revealed after heavy rains, then it’s time to repair the rendering.

(3) Side walls can be raised to the height of the vault, with the void each side filled in to make a traditional flat terrace roof.

(4) House designs and construction procedures have been standardised and 'modularised': whilst facilitating the construction process, it also means that VN houses can be extended, and window, door, and alcove openings modified as needed, in response to changing family size and needs.

Please refer to the Annex (VN Building Guidelines) and the VN Masons' Manuals included in the supporting documentation for further technical details .

See also The VN Technical Solution on our website.

www.lavoutenubienne.org

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http://www.archnet.org/

http://www.lavoutenubienne.org/spip.php?page=rubrique&id_rubrique=39


A single storey house

The standard two-vault house (living room, 2 bedrooms,shower, kitchen) has around 50 sq metres interior floor space; the usable area can be increased by transforming the roof into a flat terrace

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The labour required for such a house is around 26 man-days of two VN masons, and the same again for two apprentices and two labourers; materials needed are 30 barrows of laterite rocks, 4300 large bricks and 70 barrows of ordinary earth for the walls, 70 barrows of good quality earth for the vault bricks and mortar, and 140 barrels of water. Total cost (excluding land) for labour, materials, and basic finishes is the equivalent of around 1,200 Euros.

Construction of the vaults

Vaulted external roof version

Flat terrace roof version

Interior showing arched openings between rooms

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A two-storey house

Several two-storey VN houses have now been built

The one shown in the photos (not in the plan, which is for a five-vault house), in Boromo, has three vaults on the ground floor, with a flat roof supporting a further vault, with a roof terrace on either side.

Total usable interior floor space for the house shown inn the photos opposite (3 vaults ground floor + 1 vault first floor) is 110 square metres. Total approximate cost, excluding the site, is the equivalent of about 2,500 Euros (labour 1000 Euros/ materials: 800 Euros / basic finishes: 700 Euros) – but a significant proportion of these costs (up to 90% of labour costs) are 'compressible' , in the sense that they could fall outside the formal cash economy.

Topping out of 2nd floor vault

Completed 2nd floor vault and flat roof terrace

Interior view of staircase in construction

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4.3 Main beneficiaries

The direct beneficiaries of the project include:

(1) The builders trained in the VN technique, able to work for clients and become independent entrepreneurs on their own account

(2) The apprentices who are paid during their on-the-job training period whilst they learn how to build VN houses

(3)The families living in VN homes (and using VN constructions for their agricultural and other commercial activities) and who benefit from much increased levels of comfort compared to the tin roof houses or shacks which are often the only alternative

(4) Those involved in ancillary activities such as fabrication of mud bricks, transport of materials, extraction of rocks for foundations etc.

(5) Local associations and NGO’s who have erected comfortable VN buildings which not only provide accommodation as needed, but also serve as examples and models for the local population.

(6) Local public authorities who are now realising that some of their needs can be met through a local VN construction market, at the same time providing employment and reducing the need for imported materials and preserving local timber resources.

Overall, around 4,500 people have benefited directly from the Programme to date, in Burkina Faso, Mali, Togo, and Senegal. This includes the 300 or so families in the first main action zone of the project (Boromo). But there are also significant indirect benefits:

- a reduction in deforestation (a traditional house uses around 3 cubic metres of timber, so one can estimate a saving of some 600 cubic metres of precious timber through the construction of the existing VN buildings)

- a positive impact on local family economies, as VN buildings rely essentially on labour for their construction, with little need for cash purchase of building materials

- a significant reduction in the use of imported materials (sheet metal, cement, timber).

The project meshes well with the declared national and regional economic imperatives: creation of employment, a better management of natural resources, and raising of awareness concerning environmental issues.

4.4 Current stage and future plans

The near exponential growth of the 'Earth roofs in the Sahel' Programme over the last eight years, and the growing recognition received, have demonstrated that real needs for improved, economically accessible, housing in the Sahel are being met, albeit on a relatively small scale so far.

The accumulated project experience has shown that VN houses are affordable, safe, comfortable, durable, and aesthetically pleasing, and that the VN technique can be adapted to individual clients’ requirements. They represent a real, cost-effective, ecologically sound, sustainable, alternative to the use of imported timber and sheet metal roofing. As such, it is clear that there are many poor rural and peri-urban communities throughout the Sahel region who could benefit from discovering and adapting the VN technique to their own situations. Some early steps have already been taken in this direction: a few builders from Mali and Togo have recently been trained on VN sites in Burkina Faso, and VN builders from Burkina have been working last season on major construction projects in Mali and Senegal, at the same time training local apprentices on these sites. But much more needs to be done, on a much bigger scale.

The challenge for the coming years is to design and implement a strategy which will make possible the move from a successful small-scale project to something much bigger, with the overwhelming priorities being the recruitment and training of new apprentices, and the support of VN builders to become independent entrepreneurs, running their own VN construction businesses.

As a result of winning the Ashoka France -IMPACT Competition for social entrepreneurship in February 2008, AVN has been receiving professional support and consultancy advice in the preparation of its Social Business Plan for a medium and long-term development strategy to meet this scaling-up challenge.

In the medium-term, a reasonable extrapolation, based on the progress made so far, indicates that by 2012 the total number of trained VN builders would be around 800, and the total number of vaults built around 4,000. However, these projections assume a continuation of the present, rather modest, strategy of the opening up of a few new action zones each year, with training of new builders being reliant on actual building sites and the inputs of trained VN master builders. To bring the benefits of VN housing to the poor rural and urban families who most need them will require an accelerated scaling up of the current VN strategy, and the involvement of a wider range of partners on the ground (government

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departments, NGO’s, private and state companies, affiliated associations…), and in a wider range of countries and regions of the Sahel.

The Association is currently engaged, with various partners on joint projects in Burkina Faso, Mali, Senegal, and Ivory Coast in studying different models for this scaling up process:- dissemination through word of mouth and informal contacts,- the setting up of national bases (e.g AVN-BF, already in operation, and AVN-Mali, scheduled for 2009)- a devolved but structured and controlled approach by franchised partners.- a totally centralised approach organised uniquely through AVN-International.

On a 20 year horizon, if successful scaling-up can be achieved, we would hope to see, cumulatively, something like 50,000 trained VN builders, operating as local artisans and independent entrepreneurs, and some 400,000 homes built. At this point, a threshold (or 'tipping point') will be reached, beyond which the role played by AVN will become less and less important, as the market (product, offer, demand) for VN construction becomes autonomous, and self-generating, without the need for further intervention from AVN.

Finally, recent enquiries coming from outside the Sahel suggest that the Association needs to investigate the applicability of the VN methods to different socio-economic contexts (e.g. in the Maghreb), not only for social housing, but also for agricultural buildings, and residential villas and hotels), and to different, more humid, tropical, climatic conditions (e.g. countries such as Madagascar, southern Benin, Sierra Leone, and Sao Tome et Principe). Studies analysing the economic and technical factors concerning the adaptation of the VN methods to these new contexts need to be undertaken ibefore an appropriate response can be made to such enquiries.

4.5 Project costs and funding

The project costs are mainly to do with organisation and scaling up of the project (promotional activities, negotiations with potential clients and sponsors, recruitment and training of masons, monitoring of construction projects...), rather than capital costs per se. Actual building costs are mainly, and increasingly, met by the clients, with the Association restricting its financial input to financing of a proportion of labour costs and training for the first buildings in new zones, and for provision of plastic sheeting for roof waterproofing. For example, in 2001, of 50 salaried months of labour, 50% were

paid by the VN Association, and 50% by clients; but in 2008, of 1200 salaried months, only 12 months (1%) were paid by the Association, the rest by clients (see the latest Social Business Plan in the supporting documents). Clearly, the less financial support is needed, the closer we are getting to a self-sustaining market economy for VN buildings.

As an example of the current scale of costs, the breakdown of the 120,000 Euro budget for the 2007/08 Programme was:- running costs (admin, coordination, travel): 18% - communications, publicity : 2%- technical support (missions) : 75%- support for construction sites: 5%This budget does not include the monetary equivalent of time contributed by volunteers.

Income to the Association comes from four sources:- regular monthly and one-off donations from individuals (14%)- subsidies from the Ministry of Foreign Affairs and other public bodies in France (25%)- a voluntary contribution of 20% of construction costs for buildings such as schools and dispensaries financed by European NGO's (21%).- grants from private sector foundations (40%).

Funding from French foundations has been obtained recently for scaling up of the project in Burkina Faso and neighbouring countries: the Fondation Véolia has awarded AVN 64,000 Euros for 2007/08, and a grant of 50,000 Euros for 2008 has been made by Solidarcité/PPR. And La Fondation Hermes has very recently confirmed (Nov 2008) that they will be providing substantial funding to further support the development and expansion of the Programme.

Very positive negotiations are currently ongoing with the French Ministry of Foreign Affairs office in Burkina Faso for local funding of 150,000 Euros over the next three years, for construction of community use buildings.. Another recent example of funding from the public sector is the decision of the Communauté de Communes Val de Drome to spend 120,000 Euros over the next three years to finance the construction of VN buildings, and the training of local VN masons, in northern Senegal.

4.6 Social aspects

Around 70% of VN buildings constructed so far are family homes, with communal buildings (13%), commercial buildings such as small hotels (12%), and agricultural buildings (6%) making up the remainder.

The involvement of local communities in these

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various types of building has, inevitably, been highly significant, as the VN approach is so firmly anchored in the community and in local economic circuits. The various VN buildings erected for community use (schools, dispensaries, a church, a mosque, meeting halls…) have all involved members of the local population, and, once completed and in use, these buildings have a valuable demonstrator effect, encouraging people to think about employing a local VN artisan to build their own homes.

Clients pay the costs of their own VN houses, and most have played a major role in adapting and tailoring the standard designs to their own requirements (e.g. wiring, plumbing, different types and colours of rendering, numbers of doors and windows…).

The VN builders learn a new technique which they can use for their own business, and for training new apprentices on-the-job, which gets them heavily involved in the local community. And every VN project involves ancillary workers (brick makers, transporters, labourers, ..) who in turn benefit.

As the years go by, and it is clear that the VN houses are stable, weatherproof, comfortable, and affordable, it is clear that more and more people will shed their initial reservations about using a new (and, a few years ago in this region, untested) technique, and an increasing number of clients for VN houses will emerge in the villages covered in the programme’s action zones.

4.7 Environmental aspects

The 'Earth roofs in the Sahel' programme is promoting environmental sustainability in several ways. Firstly, because the materials used for construction (earth and water, principally) are 'environmentally neutral' (non-polluting, locally available therefore not requiring transport...). Secondly, because no timber is used in VN buildings, so this is helping to arrest deforestation in the Sahel, and the importing of sawn timber from the forests south of the region. Thirdly, because the only energy used in fabrication of bricks and in construction is human! It has been estimated that, in the first six years of the programme, something like 70 tons of CO2 has been economised in this respect (i.e. the energy resources that would have been needed to manufacture and transport metal sheet roofing panels and other materials for the equivalent number of buildings).

4.8 Economic aspects

Addressing issues of affordability and accessibility requires making cost comparisons between a VN house and the various alternatives (a traditional

Sahelian house in adobe and timber, a ‘modern’ house in concrete blocks and a tin roof, a house with earth brick walls and a tin roof…). But such comparisons are not so simple to make.

For a start, the thermal insulation / comfort qualities are very different, with a VN house being far more comfortable and better insulated from heat and cold than one with a tin roof. And, in many parts of the Sahel, the traditional timber + earth flat roof-terrace is no longer an option, so such a comparison would be spurious. And the costs of a VN house vary from region to region – higher in urban than in rural zones, because of the differences in cost of transporting earth bricks to the sites, and within a region, depending on climatic conditions (availability of water for making bricks and mortar being a key factor).

Costs of materials are very different, with imported tin roofing materials and beams, and cement and concrete blocks, costing far more in cash than earth bricks made in a village environment; but this is partly balanced by the fact that a VN house will require around three times as many earth bricks as a tin roof house. Furthermore, the proportion of labour to materials costs differ significantly from one method to another: a much higher proportion of the overall cost of a VN house is attributable to labour than for a house with a tin roof supported on sawn timber beams. And, in many rural areas of the Sahel, the labour costs may well lie outside any formal economic circuits, with neighbours trading time for building work with time for agricultural tasks.

Finally, there are differences in ongoing maintenance costs, with earth roof VN houses requiring some maintenance and re-rendering every two years or so, after the end of the rainy season; however, the skills needed for such maintenance are well-known, having been practised for generations on the traditional flat roof houses, and on communal buildings such as mosques.

In a detailed evaluation of comparative costs of VN methods with the alternatives, in Burkina Faso, Wyss1 concludes that a VN house in a rural zone can be up to 30% less expensive, on average, than an earth wall + tin roof house of the same size; however, in an urban milieu this advantage is lost, because of the cost of transporting the bricks from outside. Overall, he concludes that the advantages of the VN method lie not only in the fact that it may be cost less than an adobe / tin roof or a concrete / tin roof building, but that:- the raw materials can be extracted, made, and transported locally;

1 Wyss, U., 2005. “Projet Dissémination des techniques de construction économiques et non consommatrices de bois au Burkina Faso : Evaluation”. [Available on the AVN website]

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- the client (family, neighbours) can, if required, provide a significant proportion of the labour;- payment for labour can, if needed, be provided on a barter basis, outside formal economic circuits.

And, for sure, the VN house is far comfier and more agreeable to live in than one with a corrugated iron roof...

It is estimated that in the first six years of the Programme, local savings of the order of 60,000 Euros have been made via the programme (= the funds that would otherwise have been spent by families on purchasing imported materials).

AVN's Programme has laid down strong foundations for the development and growth of a self-sustaining market in vaulted buildings in the zones where it has been active. Of the 115 VN builders trained so far through the Programme, a proportion have set themselves up as independent entrepreneurs, recruiting and training new apprentices themselves, and pro-actively seeking out clients. Others work at a more artisanal level, constructing houses and agricultural buildings for families in their locality when asked, and taking on casual labour as needed: such work may be carried out for cash payment, or for payment in kind. Either way, economic resources stay in the local economy instead of being spent on imported building materials, and employment opportunities – albeit often part-time and casual - are created.

Since the start of the Programme, the number of paid months of employment each building season has grown almost exponentially year-on-year, going from 30 man-months in 2000, to 1200 months in 2008. And the proportion of wages paid by clients, as opposed to by AVN, has gone from 70% in 2000 to 1% in 2008, clearly demonstrating the growth of an active, self-sustaining market for VN houses.

5 Barriers encountered

These are of several orders. The major systemic barrier to the scaling up of the Programme lies in the limits to the numbers of VN masons who can be recruited and trained each year. Even with the ratio of one trained mason to one apprentice that we are currently aiming for, it will still take several more years to reach the critical mass of operational VN builders needed to arrive at the 'tipping point' of the real take-off of a mass market for VN housing. A significant proportion of the funds raised by AVN is devoted to the acceleration of the recruitment and training of apprentices, and the provision of support to existing VN builders to help them develop their

entrepreneurial skills and client base. The more funds that the Association can raise, the more efficiently and quickly will the pool of trained VN builders grow.

At a technical level, the main barrier is the seasonal lack of sufficient water for making the earth bricks; this can be overcome in many cases by ensuring that bricks are made and stocked well in advance, at the end of the rainy season, to be ready for use when the building season starts a few months later. In urban zones, the cost of transporting bricks from the countryside into the town can also be a problem.

Amongst the Programme's key target population of poorer rural families, resistance towards the acquisition of a VN home can be of several orders.

Firstly, it is a relatively new technique in this part of Africa, and reservations are often expressed about the structural soundness and durability of timberless vaults, especially in villages where there are no examples of VN houses. Such reservations tend to vanish once people have seen and visited a VN building such as a house, school, dispensary, or church in a neighbouring village, especially buildings which have survived several rainy seasons without any problems arising (as all VN buildings have so far, apart from one which the client insisted on building in a dried-up river bed which flooded during the rains). On a large scale, however, this barrier will only disappear when there is a much wider spread and number of VN buildings throughout the region to serve as examples and models.

Secondly, some potential clients are reticent about the time and effort needed to properly maintain earth-built houses, even though the knowledge and skills to do this are traditional in the region. It is true that a certain investment needs to be made each year in checking external renderings, and repairing and maintaining them as required to ensure the structure is waterproof. A 'modern' house built from concrete blocks with a metal roof carries – in principle - a much smaller maintenance load, but it is unrealistic to imagine that, in the next few decades, the majority of poor rural families in the Sahel would be able to afford such houses. The inclusion of plastic sheeting in the roof of VN houses, and the options to invest some money in tar and/or cement-based waterproofing renderings, is going some way to overcome these reservations And once people have realised how much more comfortable, solid, and safe a VN house is compared to one with a sheet metal roof, the time need for a few days each year to check and maintain the external surfaces is considered a small penalty to pay.

Finally, some members of the target population may

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have gained the impression that a VN house is beyond their means, only for wealthier families. One reason for this doubt may be that earlier projects in the region using adobe and/or timberless vaulted construction methods were, in fact, too costly for many poorer rural families, and did not take into account that most of the Sahelian people are illiterate and survive in an informal economy on less than $2 / day. Such people need grassroots housing programmes, using local materials and a construction technique which must be as simple and easy-to-teach as possible, and led by members of their communities. Only in this way will the technique be adopted on any significant scale. The fact that AVN has radically simplified the original Nubian vault technique, and that VN builders are drawn from local communities and trained on-the-job on actual construction sites, is going a long way towards breaking down this barrier. Furthermore, adoption of the VN technique can be associated with a shift from a formal cash economy in house-building, towards a more informal, culturally embedded, labour-sharing, economy, in which a good proportion of labour and material costs can fall outside the monetary system.

6 Lessons learned

The over-riding focus of AVN's activity must be to serve the vision of of helping to promote, for the people of the Sahel, permanent and sustainable access to affordable, environmentally sound, and culturally appropriate housing. What lessons have been learnt so far in attempting to maintain this focus?

Firstly, to stay as simple as possible, in the construction techniques, in the apprenticeship programmes, and in the relationships between the different actors in the Programme (AVN-International, AVN-BF, the VN builders, and our field partners).

Secondly, to stay as close as possible to the rural communities involved in the Programme, and to build the growth of the Programme on solid foundations in the informal sector, reducing dependency on the cash economy as far as is feasible.

Thirdly, the AVN per se must not get involved directly, as a building contractor – none of the VN constructions (with the exception of part of the local centre in Boromo and the SIAO show house in Ouagadougou), have been built by the Association. The role of AVN-International, and of national centres such as AVN-BF, is to put potential clients in touch with experienced VN builders, and not to finance or sell VN buildings on the account of the Association.

Fourthly, to provide an environment in which local and national centres, VN teams, and individual VN builders, reduce their dependence on the Association and the Programme, and become autonomous. The AVN does not dictate, for example, how VN builders should operate: some want to become entrepreneurs and develop a construction business, others wish to stay as one-man artisanal operations, building a house from time to time for client neighbours, maybe in exchange for labour in their fields rather than for cash, and so on. Some VN builders in Burkina Faso are talking about setting up a VN Builders' Cooperative, which is another model. The role of the Association in each case is to provide whatever help or support may be requested to reach these and other goals that may be expressed. The fact that a high proportion of VN masons in Burkina take up the invitation to come to Boromo twice a year for three-day meetings to exchange ideas, to review their successes and failures, to plan for the next building season, and to develop their expertise, suggest that they feel comfortable in the framework provided by the Association, appreciating the benefits of being members of a 'VN Community'.

Finally, to target, and to limit, the contributions of expatriates in the Programme in specific areas of expertise as and when required. Examples in the field include advice to the local AVN-BF team on IT applications and record-keeping, advice to VN builders on costing and quantity estimating, guidance to field partners on construction methods. Volunteer members of AVN-International in Europe have defined responsibilities (IT support, maintenance of the website, translations..) which are integrated into the overall Programme.

Students and post-graduates on 2-3 month attachments to the Programme in the last two years have not only provided valuable targeted inputs in a number of areas (development of support materials for VN builders, surveys, economic studies..), but have also led to the creation and strengthening of links between the Programme and academic institutions in France and Switzerland. Such initiatives, combined with the interest aroused by the AVN Website and Newsletter, help to raise AVN's profile and to integrate the Programme into the wider community of practitioners and researchers in the field of earth architecture.

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7 Innovation and Impact

7.1 Key innovative features

As the Director of Ashoka France has said : “AVN is leading one of the most innovative projects for developing economies”.

There is nothing new, as such, about a building technique based on timberless earth brick vaults: it is an age-old method found in many parts of the world, brought back into prominence in modern times through the pioneering work of the Egyptian architect, Hassan Fathy in the village of New Gourna, near Luxor. And the VN programme is not the first to have tried more recently to resuscitate the use of such vaults for domestic architecture in rural areas such as the Sahel (e.g. the Development Workshop, winner of a World Habitat Award in 1999) and southern India (e.g. Auroville).

The factors that differentiate the AVN ‘Earth roofs in the Sahel’ programme from other initiatives which on the surface, could appear similar, include the simplicity of the technique, its standardisation and modularity, and the fact that training of builders is carried out in the community, on-the-job, on actual VN sites (and not in formal training centres which, by definition, are removed from the local community). In this way, local, generally illiterate, builders familiar with earth brick construction can learn how to construct vaults fairly rapidly, in 2-6 months of apprenticeship, depending on their prior experience. The use of the VN technique is completely integrated into local economic circuits, with very little need for external financial resources, as most of the cost of construction is attributable to labour.

At the technical level, several key innovations distinguish the VN technique: (1) A strict specification of building requirements for foundations, side walls, gable walls, openings, and, of course, the actual vaults (2) Use of a stranded wire stretched between the two gable walls, along which runs a ring with a standard length of cord, to define a constant radius for each vault (3) Use of oil drums as temporary supports for forming standard size window and door arches (4) Use of plastic sheeting over the roof, covered by a final waterproof rendering to protect it from solar degradation, to reduce the annual maintenance load for the roof (5) The possibility to easily convert the completed vaulted roof to a traditional flat terrace roof structure by raising the side walls and filling in the sides of the vault (this 'flattening' of the roof also makes the structure more weatherproof)(6) The combination of the VN earth construction

technique with the use of modern materials such as reinforced concrete pillars and beams to create large open interior spaces for community use buildings such as churches, dispensaries, schools..(7) Finally, the 'modularity' of the VN technique lends itself well to three levels of customisation: - it can be adapted to suit the needs and financial resources of a wide range of clients, from the poorest rural families to wealthier urban ones; - it allows for later extension of a building, by lengthening a vault, by adding further vaults on the side of an existing one, or by adding a second storey onto an existing single storey building - these possibilities are likely to increase the popularity of VN architecture, as homes can be ’grown’ to match developing family needs; - it is simple to re-arrange the interiors of VN buildings`(e.g the adding or removal of internal partitions, the opening or closing of doorways, and window and alcove arches).

At the social and organisational level, the VN Programme’s innovations are to do with the way in which it has been implemented in local communities in Burkina Faso within geographic zones (each of c. 50km radius) during each annual campaign.

In each zone, there is a phased progression of local builders from VN apprentices > VN builders > master builders/trainers > entrepreneurs. The recruitment and training programme is to a large extent the result of a successful coupling of the support base in France (responsible for initial funding, development of training materials, negotiations with client-NGO's...) with local development and growth of VN construction activities in the field.

The model of development by zones is not the only one being used in the scaling up and replication of

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the Programme. AVN is also testing other options, including long-term partnerships with NGO's and other organisations, a franchise model, and the setting up of VN builders' cooperatives.

Regardless of the model that may be adopted in particular contexts and countries as the programme expands, a key goal is to keep the main focus on promoting the construction of VN houses for poorer rural families in the Sahel. This often means working outside the formal cash economy, and helping VN artisan builders (as opposed to the VN entrepreneurs) to operate on an informal basis in their own local communities.

7.2 Indicators of success and impact

Three principal quantitative indicators of the impact of the AVN Programme are:- the numbers of vaults built each season,- the numbers of VN masons trained,- the numbers of man-months of wages generated.

Each of these indicators has seen near exponential growth over the last nine years.

Results of the campaign (cumulative)

By the end of the 2008/09 building season, we estimate that at least 890 vaults will have been built, 200 masons trained, and 4000 man-months of wages generated.

Of the man-months of wages generated, the last eight years have seen a progressive decrease, to close to 1% in 2008, of the proportion and number of man-months paid for by the Association, a good indicator that a real market for VN houses is being developed.

Man-months of wages generated (non cumulative)

Another important quantitative indicator is the ratio of the number of apprentices trained each year to the number of masons. This is gradually increasing (currently, it is 0.6) and the intention is to achieve a ratio of 1.0 (i.e. one new apprentice will complete training each year for every trained mason). The future growth and scaling up of the Programme and the benefits it brings are critically dependent on the speed with which new VN masons can be recruited and trained.

The key qualitative indicator of the success of the programme is the high level of satisfaction of families who have acquired VN homes. The houses are reported as being more comfortable, healthier, and safer than the conventional earth brick/ concrete block + metal roof model. And every VN building erected so far, with one exception, has survived the onslaught of the annual rains (the exception is a house which the client insisted on having built in a dried-up river bed, which was subsequently badly damaged during the very heavy rains in 2007).

The social impact of the Programme can be considered in terms of the mix of different types of VN buildings – notably the proportion of family homes to other types (schools, dispensaries, mosques, guest houses, agricultural buildings...). It is the intention to maintain the current proportion of around 75% of all VN constructions as being for family homes, as that is the key aim of the Programme. However, community-use buildings serve an invaluable demonstration function for the viability of the VN technique, as well, of course, as playing their role in community support and development. They also provide opportunities for recruitment and training of local VN masons, who, once the projects are completed, can – if they so wish – set themselves up as independent builders / entrepreneurs, building houses for local families.

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Finally, it is clear that initial reservations by official bodies towards the use of earth brick structures for public buildings such as schools and rural clinics are beginning to fade – even to the extent that negotiations are currently underway for building several VN Mairies in Burkina Faso.

7.3 Monitoring and evaluation

Monitoring of the Programme is carried out at a number of levels. AVN-BF maintains records of VN builders in the country and their constructions, and also plays a role in quality control and checking of progress on sites.

All the VN builders are invited to 3-day meetings in Boromo at the start (Oct/Nov) and end (June) of each building season, to discuss and coordinate plans and to review and analyse the projects undertaken. These Congresses, held in conjunction with members of AVN-International from France, are also the occasion for exchanging experiences and practice, and for up-dating builders with training materials and technical advice.

This approach has proved so successful in Burkina Faso that it is now being replicated for VN masons in Mali, with the first such meeting held in November 2008 in Segou, attended by 15 Malian VN masons.

The fact that many of the VN masons attending the bi-annual meetings in Boromo have built houses for their own families using the VN technique has been a strong factor in encouraging take-up locally.

Ongoing and periodic monitoring in the field is complemented by external technical evaluations carried out by independent evaluators every two years. The reports of these evaluations, of the VN builders' Congresses, as well as technical and research papers produced by interns on the Programme as part of their academic work, are made available on the AVN website. In this way, supporters and sponsors of the 'Earth roofs in the Sahel' Programme can, if they so wish, obtain detailed and regular feedback on the progress of the project, and the impact of any funds or support they may have provided.

In addition, AVN's partners (e.g. the NGO's involved in construction of schools and dispensaries in Mali and Burkina Faso) carry out their own independent evaluations of their projects. The data from these various sources is regularly reviewed by the AVN Management Committee as part of the continuing management and development of the project as a whole.

8 Recognition

The almost exponential growth of the Programme in terms of vaults constructed and builders trained, and likely projections over the next few years in the target region of the Sahel, has been matched by significant increases in national and international recognition:- currently, the AVN Programme is one of 12 projects shortlisted for the World Habitat Award 2009;- in 2008 AVN won the Solidarcité-PPR stipend and the Ashoka-France IMPACT Competition for social entrepreneurship;- in November 2007, AVN was one of the 5 Laureates of the Tech Museum Awards in the Economic Development Category;- the AVN Programme was one of 3 winners (out of 86 entries) in 2006 in the Ashoka Changemakers competition 'How to provide affordable housing'.

The AVN Programme was also one of over 300 projects nominated for the Tenth Award Cycle for the Aga Khan Architectural Award in 2006; and is also a nominee for the upcoming Eleventh Award Cycle. As a result, details of the Programme, with many images of VN buildings, are now on the ArchNet site at MIT. ArchNet (http://www.archnet.org) is an

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http://www.archnet.org/


international online community for architects, planners, urban designers, landscape architects, conservationists, and scholars, with a focus on Muslim cultures and civilisations.

The Association was asked to provide a case-study for the website of the prestigious Auroville Earth Institute in India, and has been invited to make presentations at several international conferences (Living in hot deserts, Ghardaia, Algeria, Dec 2006; Terra-2008, Bamako...), as well as at the Ecole Spéciale d'Architecture in Paris2 (Sept 08).

On the academic side, the last two years, AVN has benefited from the participation of graduate students from Schools of Architecture in France (Grenoble, Nantes), Switzerland (Lausanne), and Spain (Barcelona), on attachments or internships with the AVN Programme, and their preparation of research papers on issues related to the VN methodology and development strategy.

During the last year or so, there has been increasing media interest in the AVN Programme, with several radio programmes / interviews on Radio France Internationale and France-Inter, filming for TV programmes by AITV-Radio France Outremer, and articles in the French press (Le Monde, La Croix, Midi-Libre, Maisons paysannes de France, Architecture méditeranéenne, Valeurs Vertes...). In June 2008, an article in the famous Italian design review, DOMUS, focused on the use of the VN technique for construction of a school in the region of Kati, Mali. In May 2008, an article on VN vault construction in Burkina Faso appeared in another Italian specialist review Il Giornale dell’Architettura .

The AVN website (www.lavoutenubienne.org) has been receiving on average 150 visits per day, and the emailed AVN Newsletter, which appears several times each year in three languages, has around 3,000 subscribers, the majority French, but there are 311 subscribers for the English version, and 167 for the Spanish one (Nov 08).

The media interest in the project, the various awards received, and the website and newsletters, have together stimulated much interest. Email requests for visits to the project in the Sahel, for technical information, for volunteer participation, are received regularly from people interested in earth/adobe

2 Perhaps the greatest tribute received so far was a request from a famous French egyptologist from the CNRS, at this conference, who asked AVN to provide him with VN builders to restore the ancient Nubian vaults in Ramasseum (which were built 3500 years ago).

construction, from students and researchers, from architects, from journalists and photographers..from as far away as Canada, Mexico, the USA, India, as well as from many European and African countries. An example is the visit to Burkina Faso by a team of three representatives from the Californian eco-urban property developers LJUrban in Dec 07, following publicity generated by the Tech Award.

The AVN showhouse at the Salon International de l'Artisanat de Ouagoudougou (SIAO) was extended for the 2008 Salon, with the addition of an arcade and a first floor vault and terrace.

This house aroused a great deal of interest from visitors to the SIAO (1500 AVN brochures were taken up) which is bound to generate new clients for VN builders in the Region.

9 Transfer

The 'Earth roofs in the Sahel' Programme has seen a fairly rapid expansion in Burkina Faso. Originally centred on one zone around Boromo, a further seven zones have been opened3, with a nucleus of one or more operational VN builders in each zone, recruiting and training apprentices and building houses for local clients (and/or for NGO's and other agencies financing the construction of community use buildings). In each zone, AVN-BF has often pump-primed construction of the first few houses by financing a portion of initial labour costs for the VN builder(s), and by purchasing the plastic sheeting for the roofs. Some Burkinabé VN builders are working outside these action zones (not only in Burkina Faso, but including one in Togo, and one in Ivory Coast), entirely on their own initiative, but in the knowledge that they can contact the team in Boromo if they need advice.

To support the growth of the Programme in Burkina Faso, the Association's logistical base has been strengthened with the appointment of administrative

3 See map on p. 16

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http://www.lavoutenubienne.org/


support staff, the purchase of mobylettes and IT equipment, and the plans to set up a Cooperative of VN Builders in the Boromo region.

The 'action zone' model is being replicated in Mali, near Segou, in a 'VN pilot village' with several clients already signed up with a Malian VN mason trained through AVN-BF. A coordination centre has been set up in Bamako (AVN-BF) which will provide support to VN projects in Mali at a national level, including any existing and future action zones, as well as liaison and support for projects being funded by European NGO's in the country.

Partnerships with NGO's during the last few years4 have played a major role in diffusion of the Programme in Burkina Faso, Mali, and Senegal, and will continue to be a major driver. Although most of these NGO projects are financing the construction of community use buildings, rather than individual houses, they play an important relay role through: - providing examples of well-constructed VN buildings, and thus helping overcome resistance to the technique, and persuading local families that it might make sense to invest in a VN house of their own; - providing employment for trained VN masons, and the prestige that goes with working on an 'international' project, and having helped construct a locally important building such as a school, a mosque, a church, or a health centre;- providing (often large scale) training opportunities for VN apprentices, thus accelerating the growth in the numbers of VN masons coming onto the market;bringing additional funding to the Association, which can be re-invested in the expansion of the Programme.The ultimate goal is to have more and more autonomous national teams (it terms of management but also finance). Once the market is sufficiently pump primed, the AVN team could be managed and financed directly in the field, or maybe replaced by VN builders' cooperatives.

The achievements of the 'Earth roofs in the Sahel' Programme over the last eight years, and the wealth of information on the AVN website, have aroused a lot of interest from outside the AVN's target region. Approaches have been made to the Association from individuals and organisations in Madagascar, Cameroon, Chad, Sao Tome et Principe, Nigeria, Sierra Leone, and Morocco (even from Mexico and India!), for help and information on using the VN technique and/or for the drawing up of partnership agreements: these requests have been put on hold for the moment pending the recruitment and training of more VN builders.

4 See Section 3 (pp. 6-7) above

10 Two AVN 'champions'

Dr. Cheick Modibo Diarra Africa ChairmanMiddle East & AfricaMicrosoft Corporation 3012 William Nicole Drive,Bryanston 2191 / PO box 5817, Rivonia 2128, Johannesburg,South Africa

Tel: +27 11 361 7189Fax: +27 11 361 7190email: [email protected]

[ www.microsoft.com/emea/about/executivebiographies/cheickDiarra.mspx ]

Dr. Diarra visited several VN buildings in Burkina Faso in 2008, and has shown a strong interest in the potential for social and economic development of the AVN Programme in the Sahel.

Mr. Satprem Maïni

Architect – Director Auroville Earth InstituteBASIN South Asia – MemberUNESCO Chair Earthen Architecture Representative for Asia Auroville Earth InstituteAuroshilpam, Auroville 605 101Tamil Nadu, India

Tel.: 0091 (0) 413 – 262 3064 / 262 33 30Fax: 0091 (0) 413 – 262 2886Email: [email protected] Web: www.earth-auroville.com

Mr Maini is one of the world's leading authorities on earth architecture and vault construction, and has been following the AVN Programme with great interest for several years. He has said that he believes AVN is "...the best worldwide in this field of work of transferring the knowledge of building of vaults made of raw earth..[and that]...their success is that they focus on the social aspect of this technology transfer".

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http://www.microsoft.com/emea/about/executivebiographies/cheickDiarra.mspx

http://www.microsoft.com/emea/about/executivebiographies/cheickDiarra.mspx


Annex: VN Building Guidelines

(1) Foundations Foundations are extremely important and must never be neglected > For foundations for lateral walls (60 cm wide) supporting vaults, in normal earth, a trench 60 cm deep and 70 cm wide must be dug > For foundations for gable end walls (40 cm wide), in normal earth, a trench 60 cm deep and 40 cm wide must be dug > For interior partition walls (20 cm wide), a trench 40 cm deep is sufficient > These depths can vary up or down depending on the type of ground (sand, laterite, etc.) > The foundations must be completely and carefully filled with large and medium size rocks, and banco

> For normal foundations (60 cm deep, ground neither too soft nor too hard), estimate one cartload of rocks for every 2 square metres of floor space > For two-storey buildings, increase the depth of the foundations.

(2) Construction > Load-bearing walls supporting the vault must be around 60 cm wide, built in alternate rows of large bricks (one row laid widthwise, the next lengthwise); the mud bricks normally made in most villages (more or less 18 cm high) can be used.

>The height of these walls should be 6 to 11 rows (1,40 m – 2,00 m) before the start of the vault, depending on the means and requirements of the client > The lateral walls should be continued with 5 – 9 rows of large bricks once the vault is completed, and the gap each side between these raised walls and the sides of the vault should be filled carefully to form a more or less flat roof (to use as a roof terrace, and to give improved weatherproofing and strength) > The gable end walls ( 38 - 40 cm wide) should be built in large bricks laid lengthwise; the walls should slope inwards slightly ( 1 cm per metre height)

> The partition walls (around 20 cm wide) are built in large bricks laid widthwise > Clients are advised to include many openings with vaulted lintels (use an oil drum as a former) of a maximum width of 80 cm; it is feasible to have a 75 cm opening for every running metre of external lateral walls, and 70 cm openings for every 80 cm of partition wall, and the openings can be used as doorways, or be half-closed to form windows or cupboards. Inclusion of such openings in the original structure allows for later flexibility and extension.

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> The cable guide must be stretched between the gable walls, at the height of the base of the vault, and the attached cord used to guide the placement of bricks, with each course sloping towards the gable wall.

(3) Dimensions > The internal width of the vault (and hence the floor between the lateral walls) must not exceed 3,25 metres > The length of the building (up to 12 m maximum) and the number of vaults alongside each other depends on the needs and means of the client > The internal height of the vaults can vary from 2,50 m to 3,50 m depending on the client’s needs > By lowering the internal floor level by 20 cm (one step) internal height can be increased, and extra earth made available for construction. > Two-storey buildings with an internal staircase can be built, but only under the supervision of an experienced VN builder

(4) Building Materials > For all walls: good quality banco and large bricks (of the traditional type found in most villages) > For the vaults : banco and high quality small bricks (25 cm X 12 cm X 4cm), made under the supervision of the VN builder > If the additional costs can be met by the client, walls can be built with laterite bricks, or a mixture of laterite and earth bricks

(5) Rendering and Maintenance >A layer of plastic sheeting (e.g. FasoPlast) must be included under the last layer of rendering on the roof; this guarantees a weatherproof finish which complements the external rendering > The plastic sheeting must never be left revealed, as the sunlight will damage it, and must be covered by a final coat of earth rendering

> All external renderings must be checked annually and renovated as needed, as is the custom for all earth buildings > Many traditional adjuvants can be included in the external earth renderings to increase waterproofing > For clients who want this, final renderings in cement or tar can be used to minimise the need for annual maintenance.

Provided that the state of the roof is checked annually after each rainy season, and any re-rendering - usually minimal, in fact - required is carried out, VN buildings can be expected to have a longer life-time than ones with corrugated iron roofs.

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Advice to Clients > To build a VN house, you need to use an experienced VN builder who has already constructed several vaults > You must not try to economise on the width of the walls, the depth of the foundations, and the quality of the earth used > You must carry out annual checks and maintenance of external renderings, especially of the roof

> A house can be made of two vaults side-by-side, thus economising on one load-bearing wall; two-storey vaulted houses can be built. > A house can be built little by little, over a period of several years > A flat terrace roof can be incorporated into the design > Clients are advised to start collecting bricks and building as early as possible (October, November), to benefit from the availability of water > Take care over the choice of your site and the proper evacuation of rainwater > Load-bearing walls can be built during the rainy season, especially if they are constructed from laterite bricks.

Example Estimate Here is an estimate of materials needed and labour time for a house of 52 square metres floor space, with 2 bedrooms, 1 shower, and 1 living room / kitchen (about the same dimensions as a house needing 44 corrugated metal roofing sheets): > Building materials

- 30 barrows of rocks for foundations- 4300 large bricks (38cm X 18 cm X 15 cm)- 70 barrows of ordinary earth for the walls- 70 barrows of high quality earth for the small bricks and vault140 barrels of water- 70 sq metres plastic sheeting > Labour (assuming all materials are on site)

- 26 working days for two VN builders- 26 working days for two VN apprentices- 26 working days for 5 labourers

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Documents

Association La Voute Nubienne