Affordable Housing for the Sahel

Affordable Housing for the Sahel

Organization type: 
nonprofit/ngo/citizen sector
$250,000 - $500,000
Project Summary
Elevator Pitch

Concise Summary: Help us pitch this solution! Provide an explanation within 3-4 short sentences.

In the sub-Saharan region of Africa, our Social Business sells to NGOs and local governements solutions to generate local markets that enables to spread on a large scale the use by people of timberless vaulted mud brick houses which are environmentally friendly, affordable, and comfortable (compared to houses using expensive imported sheet metal roofing and timber beams).

About You
la Voûte Nubienne
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Section 1: About You
First Name


Last Name


Section 2: About Your Organization
Is your initiative connected to an established organization?

Organization Name

la Voûte Nubienne

Organization Phone

+33 698 217 000

Organization Address

9 rue des arts / 34190-Ganges (france)

Organization Country
How long has this organization been operating?

More than 5 years

Your idea
Country your work focuses on
What makes your innovation unique?

The VN technique is the first major and replicable instance of the construction of timberless vaulted buildings in sub-Saharan Africa. The unique nature of the VN project, which differentiates it clearly from earlier initiatives, lies in several key aspects:
- the simplicity and standardisation of the VN technique
- the speed with which local, generally illiterate, builders familiar with mud brick construction can learn to construct the vaults (2-3 months of on-the-job apprenticeship on a VN building site)
- the notion of a geographic zone, of a radius of around 50km, within which the project’s campaign is centred each year, with a trained VN master builder responsible for coordinating work in the zone and liasing with potential clients
- the complete integration of the technique into local economic circuits, with little need for external financial resources (most of the cost of construction is attributable to labour)
- the comfort of the VN houses, well insulated from extremes of heat and cold, and able to incorporate traditional features such as flat terraced roofs into their construction
- the durability of the houses: since the first VN houses were built eight years ago, not a single one has collapsed or been damaged by the seasonal rainy periods.
At a technical level, several innovations distinguish the VN technique; for example:
- strict specification of building requirements for foundations, walls, openings, and the actual vaults
- the 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
- the use of oil drums as temporary supports for forming window and door arches
- the 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
- the option to easily convert the completed vaulted roof to a traditional flat terrace roof.

Do you have a patent for this idea?

Tell us about the social impact of your innovation. Please include both numbers and stories as evidence of this impact

Each VN built has lot of social impacts: this technique is more confortable, stronger, more socially and economically adapted, less polluting than tin roofs used usually. Moreover, it provides businesses and jobs for people locally.
But having a good solution is not enough. The main challenge is : how to spread it as fast as possible on a large scale ?
The most significant criterion of the success of the project's delivery system lies in the almost exponential growth, 50 to 60% year on year, in the number of vaults constructed and the number of VN builders trained and apprentices in training. In the first year of formal existence of the project (2000), 7 vaults were built and 3 builders trained; during the current campaign (2010) 230 vaults have been built, and there are now :
- 200 experienced VN builders, (including 90 real VN entrepreneurs working with us as advisers), and a further 350 undergoing training
- some 1 000 vaults built since 2000; 70% of these are in low-cost low-cost rural homes (the average home is 25 sq meter).
- some 2 000 tons of CO2 equivalent compensation (Carbon Footprint calculated by ERM)
- estimation of 400 000 € of local economies generated
- around 10 000 direct beneficiaries
In addition to homes, the VN technique has been used to construct larger buildings for community use, including churches, mosquees, libraries, several low cost hotels / guest houses, and houses for a women's associatiosn. These other buildings, because of their community focus, and community involvment in their construction, provide valuable word-of-mouth publicity for the project.

Problem: Describe the primary problem(s) that your innovation is addressing

In sub-Saharan Africa, bush timber has traditionally been used for roofing and for load-bearing
supports. However, climate change, deforestation, and increasing population growth, mean that these traditional building techniques are no longer feasible. Even in regions where some tree cover remains, the use of bush timber for construction is either illegal, or requires purchase of expensive permits.
So millions of rural families resort to buying corrugated iron sheets and sawn timber for roof-building. Such roofs have many disadvantages, especially the poor thermal and sound insulation, making houses too hot in the day, often too cold at night, and extremely noisy during the short but intensive rainy season. They are relatively fragile, can easily be damaged by wind and rain, and may even be at risk of theft. The average life of a sheet metal roof is only around ten years, as a result of rusting and corrosion, and their very fragility is a source of danger. Moreover, they are often beyond the means of many people.
They have to be paid for in cash, which is often a problem for the many families who live outside the cash economy. Finding the necessary funds can become a major drain on family resources, forcing them into a vicious circle of poverty

Actions: Describe the steps that you are taking to make your innovation a success. Include a description of the business model. What might prevent that success?

The technique has been adapted in the first 2 years of the project, between 1998 and 2000.
Between 2000 and 2008 we studied the social impact and demand for this technology.
Now we have designed a very innovative methodology to spread it as fast as possible.
This methodology has been recentrly granted by the WorldBank Development Marketplace. IT is a four-year Pilot Village and Pilot Zone Deployment Programmes (PVDP / PZDP), to help generate a sustainable local construction market in each selected region.
AVN sells this Deployment methodology to local governments or NGOs : thanks to us, these clients will achieve their objectives, generating independent businesses, taxes, social and environmental impacts quickly on the field. Once the market enough pump-primed, we can withdrow our support and draw back to new areas.
The kernel of each PVDP/ PDZP is a local 'champion' and a core group of potential apprentices and clients in an area including several villages. AVN makes available teams of experienced NV builders to train local villagers in the technique and to supervise the construction sites.
The PVDP ( Pilot Village Deployment Program) strategy, phased over a four-year period, involves:
(1) Identification of a local champion and client base for VN buildings and houses in the village
(2) Agreement with AVN on a construction schedule, and on numbers of local apprentices to be
trained on-site, Year 1
(3) AVN provides a team of experienced VN masons to construct the houses and train apprentices in Year 1.
(4) Assuming a positive evaluation, a schedule is drawn up for the next 3 years; the team of VN
masons returns to the village in Year 2 and Year 3, to supervise construction and help select and train new apprentices. The program spreads to neighbouring villages, from one village community to another.

Results: Describe the expected results of these actions over the next three years. Please address each year separately, if possible

- 750 new VN built
- 100 new builders trained
- 1 500 new tons of CO2
- 300 000 € of new local economies generated
- validation of interest in new areas (east Africa)
- partnerships with international organization (UN-habitat, PNUE, PNUD, etc)
- growth of our for-profit component (for now we were funded by philanthropy and we just begun to really “sell” our services)

How many people will your project serve annually?

More than 10,000

What is the average monthly household income in your target community, in US Dollars?

Less than $50

Does your innovation seek to have an impact on public policy?


If your innovation seeks to impact public policy, how?

We already have impact on public policies. In some regions we convinced local authorities to write about the use of VN technique for social housing and public buildings (Burkina Faso, Senegal, Mali). We work with national authorities to enable “their” people to be trained.
Thanks to World Bank who helps us validating our methodology in Burkina Faso, we know that by the end of 2012 we will have enough support and features, data, to convince national authorities.

What stage is your Social Enterprise in?

Operating for more than 5 years

Does your organization have a board of directors or an advisory board?


Does your organization have a non monetary partnerships with NGOs?


Does your organization have a non monetary partnerships with businesses?


Does your organization have a non monetary partnerships with government?


Please tell us more about how partnerships could be critical to the success of your Social Enterprise

Partnerships are considered as leverage to help us to reverse the housing issue in sahelian regions. In fact we need experts in several fields (microfinance, architecture, entrepreneurship, communication) to help us doing the job.
For example, Entrepreneurs du Monde is our Partner in Microfinance, helping us to find solutions to accelerate the pump-priming of the market through adapted financing Tools either for VN consumer or for VN Producer.
ERM and GERES are Partners to find solution through the difficult carbon financing processes.
Besix (the major Building Company from Belgium), Arquitectos Sin Fronteras and Africabougou (architectural NGOs) are technical Partner, they help us finding technical solution to meet more range of demand (larger buildings for schools, maintainance solution for more rainy areas, and so on).

We would like to learn more about how your initiative is financially supported. Please explain your business plan/revenue model

Our products are measurable and sustainable “social” impacts.
These impacts are generated through activities that aim to create, in specific areas in Africa, local markets for an accurate building technique called VN.
These impacts are sold to clients who are looking for the creation of a real entrepreneurship network, beneficiaries’ autonomy, carbon compensation, people’s employement, rural development, and so on.
These clients are companies, citizens, NGOs, governments.
Each of them has specific needs we answer to.
Until recently, we did not had enough experience to launch a real “for-financial-profit” activity, and most of our clients paid us, but wanted us to give them back a “balance 0” financial report. In other word, we had to take lot of time to explain each € of expenses instead of just doing our job.
But now we have found “real” clients that understand we need financial investments to develop, and therefore to be able to propose dividends to the investors (or social investors).
We have now to develop this range of clients so that we can raise more funds, from social investors, to develop our activity.
NB : some people tell us we should be paid by the VN entrepreneurs, but it is really not the right strategy.
- The first very simple thing is that in fact we do not sell anything to them, on the contrary they produce what we and our clients are looking for : very fast growing social impacts, autonomy. Thanks to us, local governments and their partner progressively have on the field a real network of SME, creating local jobs and taxes that will be invest in infrastructures that will help business field to develop, and so on; Thanks to us international cooperations generate autonomy on the field, and can use their money to other issues.
That is our major innovation compared to other developing organizations : ...
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The Story
What was the defining moment that led you to this innovation?

In 1998, Thomas Granier, a builder from France, and Seri Youlou, a farmer from Boromo, Burkina Faso, wanted to try to buld a Nubian Vault in Burkina Faso. Bomavé Konaté, the founder of PIAMET in Burkina Faso, proposed them to develop the original prototype VN buildings. The interest aroused by these prototypes led to the setting up of the Voute Nubienne Association and the 'Mud roofs for the Sahel' programme on a formal basis in 2000.

Tell us about the person—the social innovator—behind this idea.

Thomas Granier is a stone mason. He has always loved traveling and the human relations encountered on the way. Having practiced traditional stone masonry for 25 years, he has found in this "architectural and social adventure" a synthesis of his different aspirations.
Having been responsible on a great number of traditional masonry construction and renovation work-sites, impassioned by Africa and married to a burkinabe woman, he is a field actor that knows the reality of african masons.
His activities and responsabilities within several real estate companies have formed him in management tasks. During his many travels in India, Morocco and subsaharan Africa he has has the opportunity to create privileged relationships with building craftsmen that have shown him their vast knowledge. This field training is an essential asset to him

How did you first hear about Changemakers?

Personal contact at Changemakers

If through another source, please provide the information