VERNACULAR ARCHITECTURE: Advocating Volcanic Stone Construction as a Viable Alternative to Fired Brick in Mountainous Areas of Southwestern Uganda.

Keywords: Vernacular, Stone Construction, Sustainable development

The following discussion presents volcanic stone as a viable walling material in areas where it is abundant.  Kisoro, Fort Portal and Bushenyi located in Southwestern Uganda are areas endowed with abundant volcanic stone.  However, area residents still opt for brick walling despite the poor soils in those areas.  The poor soils produce lower quality bricks compared to the fired clay brick from other areas especially around the Victoria basin.  Natural stone possesses physical properties suited for structural walling yet in Uganda it is habitually specified for its aesthetic finish (floor surfacing and wall cladding).  In comparison to Compressed Earth Block (CEB) and Compressed Soil Blocks (CSB), stone has not been explored enough as a potential front-runner among sustainable walling alternatives.  Further, little is being done to empower local communities to meet their own aspirations as industry, economics and urban development conspire to interrupt the transition to sustainable development particularly with regards to how environmentally unfriendly materials like fired brick are propagated.

The use of stone in construction is not completely alien to our context.  According to Nnamdi (1997), stone construction in Africa dates back to over 10,000 years ago.  In fact, Shadmon (1996) writes that Stone was used for construction way before man ever started using metallic tools.  Stone construction in Africa was popular in hilly parts of Africa creating what was known as the “hill style”, Nnamdi (1997).  More recently, residents in the hilly areas of Bunyaruguru and Kasese have constructed and actually live in stone buildings as shown in Figure 1.  In parts of Kabale stone construction is evident in their stone garden perimeter walls, and stone cooking fireplaces.

Figure 1: Stone Cottage in Fort Portal and abundant stone in Southwestern Uganda

Fired brick is not indigenous to Uganda’s material palette, in fact it was never used, at least not until a century ago, when the biggest Cathedrals were constructed at Namirembe and Rubaga (Moon, 1994) under stellar supervision even during material production.  Today, the local brick industry is highly unstandardized and because of this there is an inconsistent quality of bricks most of which are irregular.  Further, some bricks are made from poor quality soils (locally know as kifufu) and are significantly weaker than the paying public expects.  Irregularities in brick configuration have led to the wasteful use of mortar as the masons attempt to deliver straighter walls. Additionally, weaker bricks contribute to heaps of debris noticed on numerous construction sites – a topic deliberated upon previously on this blog (see Building and Materials:  waste less, gain more, check the ecological footprint, October, 2015).

Indeed, potentially viable materials and construction techniques in rural societies are not being explored for their economic and environmental merit.  Unfortunately, architects in practice are not helping the situation.  Most architects in the country persistently avoid rural commissions because few, if any, people there can afford their professional fees.  As a consequence, the low-skill level fundis and draftspersons that take on these rural projects generally work with a standard brick palette as taught in technical schools.

The cost of brick construction is even higher in the mountainous areas of Southwestern Uganda, even worse, where good clay soils hardly exist.  As a result, bricks are transported large distances to service these areas further increasing the economic and environmental cost of construction.  Brick transportation in the popular small to medium gasoline trucks over rough roads could consume as much as 5MJ/tonne for every kilometre (Fraser et al, 1995).  At this rate, each truck on a regular 100km trip uses the same fuel equivalent to burning 100kg of charcoal.  Transportation delivers an avoidable carbon load of up to 0.0741 KgCO2 per kilometre (Quashning, 2016).

Reducing the cost of construction is crucial for the success of vital infrastructure such as access to housing. “The cost of an average home mortgage in Uganda is about $30,000” Muhumuza (2016).  However, according to the World Bank development indicators (2016), Uganda’s Gross National Income is $670.  On a monthly basis, that is an average of $56.  This means that on average a Ugandan committing upwards of 30% of their annual income to service a mortgage, would require 144 years for one to pay off the loan.  These sums are inflated when interest is compounded.  This indicates that even a middle-class Ugandan would need to spend well over 50% of their income to afford decent housing.  Yet still, low cost housing in Uganda is considered by Ministry of Lands, Housing and Urban development, to be that which doesn’t exceed more than 30% of the homeowner’s income (Muhumuza, 2016).

There are three dormant volcanoes in Southwestern Uganda and according to Shadmon (1996), in the eruption of a volcano, as hot lava reaches the earth’s surface, it quickly cools down, forming crystals of igneous volcanic rock.  Some of these rocks include andsite, basalts, purnice, and rthyolite.  It is important to note that any one of these stones have a higher compressive strength than the popular fired brick.  Take for example basaltic rock that is most abundant in these areas, has an uniaxial compressive strength ranging between 12-63Mpa, (Schultz, 2012) – which is higher compared to the average compressive strength of fired brick that ranges between 5-10Mpa.

Interviews revealed a general perception among residents that stone construction is expensive.  Stone is even referred to as the rich man’s material. Residents report that, stone construction requires a lot more sand and cement mortar than fired brick.  Also, due to low popularity of the material, skilled masons in the area are rare and expensive. Interviews further revealed that the construction process takes a long time owing to a longer duration required to dry the huge chunks of mortar.  The delicate process of laying the uneven stone to form regular walls, also contributes to a prolonged construction process.

The residents say that before the popularity of brick in the area, vernacular architecture was constructed using mud and wattle like in other indigenous communities of Uganda. However, unlike in other areas, people in Kisoro added small volcanic stones to the mud to create firmer walls.  The walls were then finished with chalkstone dissolved in water to create a smooth surface.  Today, there are few stone buildings in the area mostly owned by the rich.  The difference being that the wealthy use sand and cement, yet the rest use mud mortar.  However, the result is not sturdy and for this reason, some residents in search for better quality buildings opt for fired brick rather then use stone with mud mortar.

One good practice example in a similar context is Butaro hospital by MASS design group architects located in Butaro, Rwanda just a few kilometers from Kisoro with similar climate, terrain and abundance in volcanic rock.  This project made use of the local volcanic rock, but also is sensitising society through the quality of the physical structure, that there is potential in this long-ignored material.  As a result, a new industry of stone dressing, marketing and construction has been able to kick off in Butaro, creating jobs that otherwise didn’t exist as Benimana (2016) explains.  Similarly, the artisans who hand-crush stones for aggregates in Southwestern Uganda can be further commissioned to shape volcanic stone to more regular blocks that can be assembled with less mortar. Further, in this same context, there is an existing trade of hand-crushed stones for construction aggregates. Stone crushers stand a chance to make additional income from stone dressing like their counter parts in neighbouring Kenya.

Progress in material production comes down to equipping communities with the necessary knowledge and skilling.  Architecture Schools need to educate built environment professionals to be more open-minded and take pride in the heritage of this country, and the readily available materials or opportunities that our context has to offer.  This can be achieved by questioning how we build and who builds if we are to transform rural communities all over the world.

References

Ahimbisibwe, A., Ndibwami, A., & Niwamara, T. (2015). Rural (Low Income): Inspiring Communities to shape to shape their future. PLEA 2015 Architecture in R(evolution) 31st International PLEA Conference. Bologna 9th – 11th September. Ass. Building Green Futures. Bologna, pp. 62.

Ahimbisibwe, A. & Ndibwami, A. (2016). Demystifying Fired Clay Brick: Comparative analysis of different materials for walls, with fired clay brick. 36th International Conference on Passive and Low Energy Architecture (PLEA). Cities, Buildings, People: Towards Regenerative Environments. Los Angeles.

Benimana, C. (2016). Architecture That Serves The Community. Design Indaba, view on 30th October 2016. Available at: https://www.//youtube.com/watch?v=033UAUihl6w [Assessed 17 March 2016]

Moon, K. (1994). St Paul’s Cathedral. Namirembe. Karen Moon: Richmond.

Fraser, J., Swaminathan, S., and Thompson, L. S. (1995). Energy Use in the Transport Sector. Work Bank Project. Available at: http://www.tgaassoc.com/documents/energy-text&figures-dec2007.pdf [Assessed 12 November 2016]

Muhumuza, M. (2016). The low-cost housing myth in Uganda, Daily Monitor, viewed on 26th October 2016. Available at: http://www.monitor.co.ugbusiness/Prosper/The-low-costhousing-myth-in-Uganda.”688616-3370372-b5x62qz/index.html> [Assessed 10 February 2017]

Nnamdi, E. (1997). African Architecture: Evolution and Transformation. McGraw-Hall, United States of America.

Odongo, J. & Lea, J. (1977). Home Ownership and Rural-Urban Links in Uganda. The Journal of Modern African Studies, Vol. 15, No. 1 (Mar., 1977), pp. 59-73, Cambridge University Press.

Olweny, M. (2006). Technology and Architecture Education in Uganda, The Architecture Science Association

Olweny, M. (2007). Politics, Religion, and Architecture in Uganda, in Loo, s. and Bartsch, K. (eds) Panorama to Paradise, Proceedings of the XXIVth International Conference of the Society of Architectural Historians, Australia ‘and New Zealand, Adelaide, Austria 21-2a September.

Ochola, D. (2016). The return of the stone craftsman to Kenyan Architecture, David Ochola Architect. Available at http://davidchola.com/architecture/green-architecture/the-return-of-the-stone-craftsman-to-kenyan-architecture/ [Assessed 02 April 2017]

Quashning, V. (2016). Statistics: Specific Carbon Dioxide Emissions of Various Fuels. Erneuerbare-Energien-und-Klimaschutz.de. Available at: http://www.volker-quaschning.de/datserv/CO2-spez/index_e.php [Assessed 13 March 2017]

Shadmon, A. (1996). Stone: An Introduction. London. Intermediate Technology Publication Ltd.

Schultz, R. (2012). “Brittle strength of basaltic rock masses with applications to Venus.”, 21 September, 2012, Journal of Geological Research.

SSA: UHSNET. (2015). Challenges of Low Income Earners on accessing building materials.  Shelter and Settlement Alternatives: Uganda Human Settlement Network.  Available at http://www.ssauganda.org/index.php?option=com_content&view=article&id=116:building-materials-uganda&catid=83&Itemid=296. [Assessed 7 October 2015]

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A tripartite approach to dealing with embodied energy in housing

For any worthwhile discussion, explication of any phrases that might otherwise cause undesirable hesitation is key. We begin therefore by shedding light on embodied energy. This is defined as the energy consumed by all the processes associated with the production of an object. In the context of building construction, processes included within embodied energy analysis (EEA) include the mining and processing of the natural resources used to manufacture, the manufacture, transport, delivery and installation of a product. Embodied energy is an emerging key consideration in housing today primarily because of the impacts (perceived and real) that energy production has on the environment.

Today, housing is a complex issue; and how intriguing it is that it extends beyond the physical dwelling and encapsulates psychological notions, i.e. human ideals, needs, wants, aspirations, and economic ability. As such, in its pursuit of making a contribution towards reducing the embodied energy of housing, the ELITH project proposes a multi-pronged approach – aligned with the complexity of the housing as it is understood or misunderstood and later shaped. This approach includes:

  • Fronting the value in contextual material selection and application
  • Promoting the ability of community partnerships to propagate knowledge, expertise and appropriate technologies
  • Skilling a formally educated sustainability professional to impact on a largely informal sector

Appropriate material selection and use is the primary focus for reducing the embodied energy involved in construction. This is because the decision to use a specific material impacts on extraction, manufacture, transportation, and waste generation from construction. In Uganda and the world as a whole, changing living patterns and trends are leading to the replacement of vernacular architecture, which emphasises the use of local building materials and low-energy use with more modern building interventions (Alyami et al., 2013). These methods, while providing undeniable benefits such as durability to construction, it is hypothesised, may not be the most suitable for all applications. While the importance of reducing the embodied energy in housing is appreciated from mostly a scientific point of view, the same cannot be said from a layman’s perspective. As such the ELITH project explores a grassroots and participatory process through a material selection tool that supplements existing determinants for material selection such as initial (purchase) cost, availability and ease of use – determined to be common objective drivers for material selection with additional parameters that wholly encompass sustainability criteria – social, economic and environmental impacts such as: environmental impacts of extraction and manufacture, thermal and acoustic properties, toxicity and cost of maintenance, above all, paying keen attention to the sum of these criteria and how a material/process/technology still scores against embodied energy.

The project extends its knowledge and capacity function beyond the trained built environment professional in order to grow a society grounded in the process of material selection and later construction that is well informed about and understands embodied energy in the construction of housing.

Through its interaction with promoters of various innovations within the construction industry, the ELITH project has determined that a key stumbling block for the uptake of new ideas – such as the materials selection tool proposed prior, et al. is the propagation of knowledge that challenges rooted conceptions. To this end, the study queries how community partnerships can be emulated as both a development and problem-solving model.

Embodied energy and saving on energy use are a quantifiable variable that could be shared with the masses. When people know how much they stand to gain and subsequently experience the cost savings as a result of sustainable practices, the project objectives will be taken on as community initiatives with a ripple effect that can also serve to embellish the findings and quantitative reports of the study.

The crux of the matter is the conversation on embodied energy and the possible benefits of this consideration to an individual or his/her community.

During their community development project Alwan and Jones (2014) results indicated that while operational energy was more significant over the long term, the embodied energy of key materials could not be ignored, and that it was likely to be a bigger proportion of the total carbon in a low carbon building. The components with high-embodied energy were also identified. Their design team responded to this by altering the design to significantly reduce the embodied energy within these key components – and thus made the building far more sustainable in this regard.

A contextual equivalent wound be to analyse walling elements, considering they cover the most significant surface area of most buildings, then call attention to the amounts of fuel required to prepare the units that build these elements. Firewood is a quantifiable resource particularly in local communities where it serves as the primary fuel for food preparation.

The current study is also cognisant of the fact that knowledge ought to be nurtured and promoted, as such, built environment professional at the forefront of the evolution of technologies, form an important link between the community and innovations within the industry. A key concern though is how well educated and aware the built environment professional is, and how the system within which they exist encourages this, or an improvement in the state of affairs.

The issues to consider also spell out a possible approach in themselves; and may include:

  1. The prevailing ethical dilemma and whether professionals understand their liability.
  2. The concern about cost like it was just a numbers game, without stopping to consider the future value of buildings.
  3. If built environment professionals stop to consider issues of social equity or are they indeed too elitist to deal with health, safety and wellbeing leaving it for the social scientist?
  4. Overall the ethos of managing and promoting an attitude that thinks about how to avoid/manage/mitigate risk in view of the fact that someone has to take ownership of it all.

These four points give a good indication of where to place emphasis in order to promote sustainability in a largely informal sector. There is a deliberate attempt to encapsulate all the tenets of sustainability in the discourse that is social, economic and environmental aspects, giving them all equal importance. While this may create a larger and more enigmatic concept it is worth noting that: in developing countries, the average standard of living is much lower than in developed nations and in many instances, the challenge is to meet basic human needs. The emphasis here should therefore be on development (and assessment tools) that aim to address these basic needs while avoiding negative environmental impacts (Gibberd, 2002). The ELITH project therefore envisions itself as a prelude in the development typology suggested by Gibberd’s narrative. Efforts in reducing embodied energy in construction have widespread implications; infrastructure (including housing) development is prerequisite for development – has to happen in a sustainable manner.

REFRENCES

ALWAN, Z., JONES, P. 2014. The importance of embodied energy in carbon footprint assessment. Structural Survey, Vol. 32 (1), 49 – 60

ALYAMI, S. H., REZGUI, Y. & KWAN, A. 2013. Developing sustainable building assessment scheme for Saudi Arabia: Delphi consultation approach. Renewable and Sustainable Energy Reviews, 27, 43-54.

GIBBERD, J. 2002. The sustainable building assessment tool: assessing how buildings can support sustainability in developing countries. Built Environment Professions Convention. Johannesburg, South Africa: Document Transformation Technologies.