Low-carbon climate-adapted housing large-scale dissemination

Millions of Sahelian families lack access to decent housing.

Most of them live in precarious unhealthy tin-roof shacks while living under the hottest temperatures in the world, being at the forefront of climate change.

Inappropriate expensive construction materials and techniques

Deforestation and desertification in the Sahel have led to the disappearance of bush timber and straw used in traditional architecture. ‘Modern’ technical alternatives and the materials they require (cement, steel, corrugated iron roofing, girders, etc.) as well as the monetary systems which their use entails (imports, use of cash) are not adapted to climate nor economic realities. The extreme discomfort imposed by sheet metal roofing (but also by cement brick walls) weighs heavily on sanitary conditions and school results (extreme heat, cold, and noise discomfort during the rains). Sheet metal roofing are more and more often blown off by strong winds, a phenomenon aggravated by climate change, involving heavy repair costs straining fragile families’ savings.

Even the environmentally friendly compressed earth blocks (CEB) are not really adapted to mass local adoption in the Sahel. Indeed, their production requires some cement (with the recent inflation, its cost has significantly increased; in Ghana, its price has even doubled) and a mechanical pressing machine (an expensive investment).

The Sahel is one of the poorest regions in the world, people have nothing. A construction technique to be massively adopted, both by families and masons, must require as little monetary investment as possible.  

Poverty, inappropriate vocational training, lack of jobs and revenues

In the Sahel, almost half of the population lives below the poverty line. Subsistence farming employs 80% of the working population. However, it is mainly seasonal work that keeps farmers busy only during the rainy season (from June to October). Thus, it does not provide employment and income spread over the year. Complementary off-season job opportunities are vital as well as appropriate vocational training. Indeed, the region has one of the lowest school enrolment rates in the world. Many vocational training projects have not had the expected impact due to an overly formalized pedagogical approach (e.g., in training centers), too high expected levels of basic education (given general illiteracy), few professional opportunities, poor consideration of the financial realities of learners, etc. It is therefore essential to provide inclusive dual vocational training (combining on-site learning and inclusive academic modules) fully integrated into a market dynamic creating local employment.

The population growth is estimated to increase by 150% in the Sahel before 2050. The needs for homes, local jobs, and a viable local economy will follow the same trend. The Nubian Vault Association (AVN) is working to solve the massive challenge of providing decent affordable quality housing, adapted to climate change and socio-economic realities in the Sahel, for the many, and as soon as possible.

Since 2000, our goal has been to develop a large-scale sustainable market for green affordable housing in West Africa, providing vulnerable populations access to low-carbon climate-adapted homes, at the same time as creating green jobs and strengthening economies at all levels.  

1/ The Nubian Vault technique, a construction alternative particularly adapted to climate and socio-economic realities in the Sahel

The Nubian Vault technique (NV) is both ancestral and innovative, based on local materials, economies, and knowledge. This 3,000-year-old architectural technique consists of building houses entirely with mud bricks including the earthen vaulted roof, using local materials with little carbon impact (earth, rocks, and water).

There is no use of timber, tin, cement, or any costly high CO2 footprint imported construction materials. Compared to other construction techniques, it does not require complex equipment or expensive tools, just a brick mould, a bucket, and a wheelbarrow. The Nubian Vault technique is particularly appropriate to the socio-economic realities of the region: simple, inexpensive, and frugal, enabling Sahelian families to self-build their house for the most part.

Nubian Vault buildings are also particularly adapted to extreme climate conditions offering an average gain in thermal comfort of about 7 degrees Celsius and resisting heavy rains and violent winds.

2/ A market-based approach to ensure the development of a sustainable eco-construction market

The Nubian Vault Association (AVN) has applied a market-oriented approach, thus ensuring the relevance of its solution and creating the endogenous and sustainable engine to enable its large-scale dissemination. Therefore, AVN’s objective is not to build houses but to build a self-sustained Nubian Vault housing market. Our mission is fulfilled when we can withdraw from a locality when the market is strong enough to continue its development on its own over the long term.

To this aim, we are simultaneously:

• Supporting the offer through a dual vocational training program. AVN has simplified and standardized the technique so it can be readily taught to young rural people with little or no schooling (young farmers with no activity during the dry season). Nearly 1,200 apprentices, masons, and artisans are trained and active in the Nubian Vault market.
• Supporting the demand by raising awareness about the benefits of the Nubian Vault concept and providing support to kick­starting local Nubian Vault markets. Financial incentives, an essential lever for rapid market growth, are distributed to rural families. At the same time, microfinance operators are encouraged to join to sustainably develop new adapted housing loan products.

• Supporting a positive business ecosystem by mobilizing all the relevant stakeholders in disseminating the Nubian Vault market and ensuring its perpetuation (operational partners, relay partners including political actors, technical partners, and financial partners).

3/ An operational and replicable methodology enabling a large-scale deployment

A key point of our strategy is the training and transfer of our methodology to operational partners, locally embedded community partners (farmers’ organizations, women’s groups, etc.), incorporating responses to the housing challenge into their missions, thus guaranteeing strong and growing impacts.

The entire program primarily targets the most fragile populations within five West African countries, themselves among the poorest countries in the world: Burkina Faso, Mali, Benin, Ghana, and Senegal. Our priority target beneficiaries are rural communities, living mainly from subsistence agriculture and working mainly in an informal economy.

1/ Improving Sahelian rural families' living conditions: Nubian Vault houses offer greatly improved comfort thanks to its natural thermal and acoustic performance, thus improving health conditions.

2/ Providing vocational training and jobs to rural youth: Nubian Vault construction requires the mobilization of a strong local workforce off-season (providing additional cash income during the 6 to 7 months period of agricultural inactivity). Thus, the money traditionally invested in expensive imported construction materials is redirected instead to pay for this local labor force, contributing to local economic reinforcement.

3/ Providing capacity building to community-based organizations (AVN's operational partners): these local actors benefit from training, support, and capacity building from AVN.      

The development of the Nubian Vault housing market contributes to the resilience and stabilization of Sahelian communities, youth vocational training and employment, rural development and local economy reinforcement, and climate adaptation + mitigation.

The Nubian Vault Association (AVN) was established in 2000 by Thomas Granier (a French mason), and Séri Youlou (a Burkinabe farmer). They met in Boromo (Burkina Faso), during the PIAMET (a local exhibition of traditional arts) where they first tried to build a Nubian Vault. Thus, our program started in the field and was co-designed by a Burkinabe farmer, who was himself facing the various challenges of the region.  

Since then, we have maintained this bottom-up culture and proximity to the communities we serve, from which most of the AVN teams in Burkina Faso, Mali, Benin, Ghana, and Senegal (46 people - 4 national offices and 12 regional offices) come. The team in France (10 people) is mainly composed of master’s degree graduates. This diversity and complementarity of backgrounds enable our team to work at the same time with the rural Sahelian communities, as well as with international organizations, Ministries of European and African States.  

Our strength is also our network of 40 operational partners, local community-based organizations such as women’s groups and producers organizations  (-> read more about our operational partners), allowing us to intervene as closely as possible with the targeted rural populations.

The design of the program is continuously being improved, based on the feedback from our teams and operational partners in the field; the masons, and apprentices we train; and of course, the beneficiaries using or living in Nubian Vault buildings.

6,700 Nubian Vault private and community buildings have been completed since the year 2000, including 1100 built during the 2021-2022 season only.

• 63,000 direct beneficiaries are living in or using Nubian Vault buildings in 1,700 different localities in 6 countries (Burkina Faso, Mali, Senegal, Mauritania, Ghana, Benin)

Rural Sahelian family living in a Nubian Vault house

• 1,320 apprentices, masons, and entrepreneurs have been trained by AVN and are now active with revenues on the Nubian Vault market, including 450 new apprentices in 2022. 

Masons and apprentices building a Nubian Vault house

Since the beginning of the program, we estimate that 6 million euros have been generated in local economic circuits. Thousands of people benefit from the reinforcement of the local economy.

Scale-up and business model

After more than 20 years the program has proven its worth and is now poised to significantly scale up its operation. To successfully achieve this new step in our journey, we need to access new networks and partners; join a community to share experiences, strategies, difficulties, etc. We will not achieve the change of scale of our program by ourselves, joining the MIT Solve community would be a changemaker.

We would mostly need support to work on the hybridization of our business model. Indeed, as an NGO, we are mostly funded by grants from institutional donors (bilateral aid agencies, multilateral aid organizations, private foundations). One of the difficulties is that donors prefer funding projects over the program. We are struggling to find sufficient, appropriate, and continuous funding to keep developing our program.

Recently we started thinking about developing a complementary business entity – serving our social mission - to generate revenues to mobilize social/impact investors. There are various options and possibilities to explore, we believe it is an important lever for the change of scale. We would need some coaching, advice, and support in this area maybe even sourcing a talent to join our team.

Reading about 2022 MIT Solve Challenge finalists and semi-finalists' business models was really inspiring. Sharing thoughts and experiences on this topic with other Solvers will be a great help!

What makes our solution innovative is our systemic approach more than the architectural technique itself. Our program aims at providing decent adapted housing to Sahelian rural families, but also better thermal performance community buildings (schools, health centers, agriculture buildings); providing vocational training, jobs, and revenues to young rural people; mobilizing and reinforcing local community-based organizations; advocating for a change in public policies on the construction sector and the right to decent housing in the Sahel; fostering rural development and reinforcing local economies; enabling climate adaptation and mitigation impacts.

A standardized technique

AVN’s first innovation was to simplify the Nubian Vault technique so it could be taught and appropriated by illiterate masons. This 3000-year-old architectural technique originating in Upper Egypt, historically unknown in other African regions, was identified by the NGO Development Workshop in the 1980’s as a potential solution to the serious housing problems of the populations of sub-Saharan Africa. From 1998 onwards, AVN started to investigate the technique again, with a view to simplifying and standardizing it so that it could be more easily adopted by local populations. After a series of technical trials in Burkina Faso, a streamlined method was evolved – the Nubian Vault (NV) technical concept – adapted to the traditional know-how of the Sahel, easy to implement, and adapted for large-scale dissemination.

A scalable market-based approach

Designed to be easily transferred to local community-based organizations, our market-based territorial dissemination methodology enables the program to be replicated in all the countries of the Soudano-Sahelian strip, and maybe one day in other regions of the world facing the same issues and climate conditions.

AVN supports the offer (by training masons) but also supports the demand. If 75% of the cost of the house is brought in-kind by the family, partly self-building its house, 400€ is needed in cash to pay the salaries of the masons, the doors, and the windows. Such an amount of money is a major barrier. Tests on the field have shown that if a family is given a 300€ financial incentive, they can manage to find the complementary 100€. Such incentive mechanisms are already in place in European countries to encourage the energy renovation of existing buildings and are all the more legitimate for the Sahelian populations who are the most exposed to climate change when they have contributed the least to it. There are virtuous because they support the development of the masons' business model and guarantee their salaries.

A carbon credits funding mechanism

Supported by UNDP and the French Global Environment Fund, AVN has launched the implementation of a carbon credits mechanism (valuing not only carbon reduction but also co-benefits) to fund these financial incentives: Low-carbon Nubian Vault houses avoid CO2 emissions justifying the issuance of carbon credits -> their sale finances the distribution of incentives to rural families -> leading to the construction of new low-carbon houses -> more CO2 avoided and carbon credits issued, and so on.

The project articulates mitigation, adaptation, and rural development.

Our purpose is the development of a sustainable self-sustaining earth eco-construction sector in the Sahel, able to operate without AVN's support and funding in the long term. 

Our impact goals are:

• Better living conditions for rural Sahelian families accessing affordable, decent, climate-adapted housing.

•  Employability, jobs, and revenues for the local rural population, and local economy reinforcement.

• Climate adaptation and mitigation.

To achieve these impact goals, below are some of our priority actions for the next five years:

• Diversifying our business model, creating a complementary business entity (whose major shareholder would be AVN and whose purpose will be to serve our social mission) generating revenues to raise investments.
• Implementing a carbon credits mechanism, valuing not only the carbon reduction but also the co-benefits of the Nubian Vault constructions (5 years project funded by UNDP and the French Global Environment Fund).
• Geographical expansion, opening new regions in the countries where we are currently operating but also in new countries of the Sahel.
• Developing the capacity of the informal Nubian Vault sector to answer the formal sector (reinforcing entrepreneurship training for the rural masons, supporting the creation of design studios to link rural masons with clients from the formal sectors, etc.).
• Reinforcing advocacy at regional, national, and international levels, for better integration of housing issues in the aid programs and national public policies.

Next year, we will:

• Keep supporting the development of the Nubian Vault market in Burkina Faso, Mali, Benin, Ghana and Senegal.
• Get support and advice to define a complementary business model to generate revenues.
• [New project starting] Start the certification process of our carbon credits and co-benefits - funded
• [New project starting] Incubate design studios/construction management services in Senegal to link earth eco-construction rural masons from the informal sector with clients from the formal market - partly funded
• [New project starting] Train a group of Sahelian leaders to advocate for the right to climate-adapted housing, at local, national, and, international levels - partly funded
• Reinforce our “Market tool” digital database to better monitor progress - funded
• Start deploying our program in Togo – grant proposal submitted. 

AVN tracks a series of indicators measuring the evolution of the Nubian Vault market and its associated impacts. AVN collects and compiles its data in its “Market Tool”, a personalized database. A system of monthly collection and feedback of field information from regional offices to national offices and then to headquarters is operational. This data is then processed and analyzed at headquarters, providing elements of capitalization and management of the program.  

Number of Nubian Vaults built:

• In 2000, our program enabled the construction of 10 Nubian Vaults during the year.
• in 2010, 100 a year were built.
• in 2020, we reached 1,000 a year,
• -> our goal is 10,000 a year by 2030. 

Over the first 22 years of activities, the indicators measured, and results achieved are as follows:

• 63,000 direct beneficiaries living in or using Nubian Vault buildings in 1,700 different localities in 6 countries (Burkina Faso, Mali, Senegal, Mauritania, Ghana, Benin)
• 36 operational partners - community-based organizations mobilized (farmers' groups, women's groups, etc).
• 6,700 low-carbon Nubian Vaults built, including 1000 during last season only.
• 1,320 apprentices, masons, and entrepreneurs have been trained by AVN
  and are now active with revenues on the Nubian Vault market, including 450 new apprentices in 2022. 
• 6 million euros have been generated in local economic circuits.
• 173,000 t-eq of CO2 avoided.

• 20 % average annual growth of the market over the last 10 years.

NV : Nubian Vault

Origins

Invented during Antiquity in Nubia (present-day Upper Egypt) to respond to a lack of timber resources, and historically unknown in other African regions, the Nubian Vault technique makes it possible to build dwellings with vaulted roofs without formwork, using local materials (mainly earth), simple tools and basic technical skills. After more than 3500 years, ancient earth brick granary vaults are still standing at the site of the Ramesseum in Luxor.

Granaries of the Ramesseum - Egypt

This technique was identified in the 1980s by the NGO Development Workshop as a potential response to the serious housing and construction problems faced by the populations of Sahelian Africa. AVN simplified and standardized the technique to facilitate both its appropriation by local populations and its large-scale dissemination. The result is a refined and frugal method –the Nubian Vault (VN) technical concept – adapted to the climate and socio-economic conditions and the traditional know-how of the Sahelian regions.

Main benefits

Nubian Vault (NV) buildings have the following benefits:

• Climate Change Mitigation with a sustainable and low-carbon construction technique using local materials.
• Adaptation to climate change with buildings offering satisfactory thermal comfort in the event of extreme temperatures.
• Access to a robust, affordable building with low maintenance costs for different sectors of activity (housing, schools, health centers, offices, granaries, workshops, markets, etc.).
• Reinforcement of the local economic environment with vocational training, labor-intensive construction sites and the mobilization of local actors.

Architectural concept

The diagram below presents the Nubian Vault architectural concept as simplified and standardized by AVN. These simplifications and the standardization enable the widest possible dissemination of know-how and the minimization of the risks of poor workmanship and damage. This architecture is characterized by a semi-circular vaulted roof of 330 cm maximum width, constructed with small earth bricks and earth mortar without any formwork. This vault rests on large load-bearing walls, built with traditional adobes, which rise to cover the vaults to form a roof terrace.
The roof terrace is flat, and the side walls are straight. These mud brick surfaces can be protected from rain erosion by various techniques (bituminous coatings, cement coatings on stone-encrusted adobes, breeze blocks, concrete parapets, etc.). The entire structure is made of earth bricks and mortar. Foundations are made with rocks and/or rammed earth and earth mortar. Load-bearing structures in earth or concrete (arches of solid blocks) or reinforced concrete (post/beam system) allow for wider interior spaces by replacing or supplementing load-bearing walls, gables and partitions. This architecture, which can include a second storey and the use of flat roof terraces, is well adapted for later additions and extensions.

-> For more information, the stages and techniques of Nubian Vault construction are illustrated in a simple manner in the following document: the Nubian Vault (VN) technical concept.

It is worth mentioning that AVN is constantly working on additional technical answers to make these Nubian Vault constructions suitable to various applications: floor building, large surfaces, solutions against erosion or to reduce maintenance, etc.

Typology of building

The Nubian Vault is a technique that is appropriate for private and community use in both rural and urban environments:

• The Nubian Vault for private housing -> watch the video

Rural house in Burkina Faso

Rural house in Mali

Rural house in Mali

• The NV for community use -> watch the video

School
 

Health Centre

Oignons storage buildings

Administrative complex including offices, meeting rooms, housing, etc

A low-carbon construction

The environmental impact of the Nubian Vault concept is one of the least damaging of all the architectural techniques currently used in Africa. Nubian Vault construction does not require any use of timber resources and reduces considerably the need for exogenous building materials with a high CO2 footprint, industrially produced and /or requiring long distance transport (steel girders, zinc metal roofing sheets, cement, sand, gravel etc.). 

Compared to other type of constructions, the Nubian Vaul buildings' benefits are:

• A flattening of average annual temperature extremes of 5 - 7 °C.
• Cold discomfort (temperature < 20°C) very rare or inexistent.
• Extreme heat discomfort (temperature > 37 °C) significantly reduced as compared to a building with a zinc or concrete roof.
• The construction of a Nubian Vault and its use over a 30 years period under acceptable conditions of comfort leads to a saving of 0,8 tons eq. CO2 per m2, as compared to other construction methods, of which 20% is due to the construction process, and 80% for usage.

Charter and codes of conduct

AVN signed and follows the following charters and codes of conduct:

• "A shared ethic" Charter of Coordination SUD and its members (adopted in November 2019)
• Code of good conduct of the German NGO Welt Hunger Hilfe (adopted in November 2019)
• Code of conduct of the Swiss Federal Department of Foreign Affairs in the framework of the PAFPA project (signed in January 21)
• Code of conduct of the DRC - Danish Refugee Council (signed in May 2021)
• Code of conduct and ethics of AVSF - Agronomists and Veterinarians without Borders (signed in September 2021)
• Code of conduct the UNHCR (currently being signed)  

These codes include commitments such as “Fight against all forms of harassment, intimidation and exploitation”, “eliminate discrimination” or “promote gender equality”.  

AVN wrote and adopted a Code of Conduct on Prevention of and Response to
Sexual Exploitation and Abuse in International Assistance since July 1,
2019.

Diversity and inclusivity

Our team includes people with no or little schooling as well as graduates with Master’s degrees, ranging from 25 years-old to 80 years-old. In the field, we work with people from all local ethnic groups and religions. Our Committee of Directors is composed of three women and one man.  

The success of our program depends on the variety and complementarity of our team’s profiles, culture, stories and background, experience and expertise.  

Concerning the training courses to become a mason or an apprentice: no educational level is required, they are delivered in-situ which makes them particularly inclusive.  

AVN promotes the selection of women's groups in the key role of operational partner (to deploy AVN’s methodology) and advocacy leader. Indeed, women are best able to talk about the benefits of adapted housing on their family’s health and well-being. Moreover, women are often in charge of expenditures associated with the family home, they usually bear the cost of the inappropriate imported building materials or the burden of repairs. In some regions of West Africa, they are also traditionally undertaking the rendering of the walls of their houses, and do the same for their Nubian Vault homes. They particularly appreciate the comfort, durability, and solidity of Nubian Vaults, as they are the first to suffer from inappropriate housing.

We are an NGO running a development program in the Sahel. So far, we have been mostly funded by grants and donations.

The main beneficiaries of the program are:

• The Sahelian families receiving a financial incentive to build their Nubian Vault house = 20% of the global cost of the house = 75% of the cash needed (self-building covers most of the cost of the house).
• The young rural people who are given the Nubian Vault masonry vocational training. Trainees are remunerated during the training.
• The trainers masons who are paid by the program to deliver the training and are given continuing updating training.
• The trained masons and their teams for whom we can provide construction projects. Most of our grant proposals includes construction projects and paid days for the masons.

• The community-based organizations partnering with AVN to deploy the program on their localities - they receive capacity building and remuneration.

We are exploring new options to move towards a self-sustained funding model, less and less dependent on donors: sale of carbon credits on the voluntary carbon market, creation of a for-profit construction management business entity to mobilize investors aiming at providing more jobs for the masons and their team, etc.

1/ Selling carbon credits to fund financial incentives to rural Sahelian families

Once the first investments have been made in a locality (to mobilize local partners, train masons, raise awareness about the benefits of the Nubian Vault houses, etc.), the only barrier for the adoption of this resilient housing concept by the local population is the lack of cash. The 400€ to pay for the salary of the mason and its team are out of reach (it represents 25% of the global cost of the house, as it involves self-building). AVN has demonstrated that a financial incentive amounting 300€ can overcome this financial barrier. 

How to fund these financial incentives? Carbon credits could be the answer!

Last November, we launched our carbon credits scheme: Climate Solidarity Co2ntribution (because it integrates strong co-benefits for the communities: adaption + rural development).

We ran a market test (50+ high qualified prospects), meeting with various companies interested in carbon offsetting. They showed a lot of interest, but asked for carbon certification (Gold Standard or Verra).

We have just obtained a grant from the French GEF (FFEM) to fund the carbon certification + the labelisation of our co-benefits.

One year's revenues from carbon credits (based on the number of Nubian Vault houses build) could fund the distribution of financial incentives for 1,2 times more houses the next year, and so on. The development funds (grants) will keep financing the emergence of the Nubian Vault market in a region, and the revenues from carbon credits will take over to support the development of the market in the long term.

2/ Construction management services to provide more jobs for the masons

We are thinking about creating a for-profit/business entity to raise investment capital.

There is a growing demand for low-carbon eco-construction buildings from Northern development donors (who fund most of the community buildings), and from some diaspora/middle class communities (in Senegal in particular).

However, the current Nubian Vault eco-construction sector cannot not respond optimally to this demand from the formal sector. Indeed, we lack the project management actors (the technicians, design studios and architects) trained in earth eco-construction and able to link the formal sector with the masons from the informal sector. We need actors able to respond to calls for tender, prepare technical files, make quotations, conduct studies, design plans, ensure the proper management and quality control of the project.

The business model is still to be defined. It could be one large company contracting with masons from the informal sector, or an incubator/impact fund to invest in various formal eco-construction micro-enterprises. We need advice to set up the more relevant model. Then we will need investments to recruit a team, rent an office, mobilize cash flow, etc. (no investment in equipment is needed as the frugal Nubian Vault technique mostly requires labor force and only basic tools).

1/ Program-based grant with the French Development Agency

At the end of 2022, the French Development Agency renewed it support to AVN by signing a program-based 3 year agreement renewable 3 times.

2/ Selling carbon credits

Even thought our carbon credits are not yet certified by an international standard, we did sell some to NGOs who believe in our program and do not need the "certification stamp".

Obtaining the grant from the French GEF (FFEM) to start the carbon certification + co-benefits labelisation has been a major achievement. Being on track towards certification, a major construction company chose our carbon credits to offset its emissions.

Our carbon credits project is also funded by the United Nations Development Program.

Our carbon credits are registered on Planetair and SWEEP carbon credits catalogues.

So far, we have generated revenues of 84,000 Euros thanks to our carbon credits.

3/ Construction management services business entity

We've just obtained a one-year grant from the Jeankerber Foundation to start the training and incubation of construction management micro-enterprises/design studios to be trained in the earth eco-construction sector in Senegal. We have partnered with the Italian eco-construction design studio Chiwara. Amongst the activities, this grant includes the definition of a broader business model and a 5-years roadmap so we will be able to dedicate the necessary time.

Thank you for reading our application!!