TRADITIONAL BURNED CLAY BRICKS CONSTRUCTION
Providing adequate housing in developing countries remains one of the most critical needs for low-income groups. However, meeting this demand is challenging because land and construction costs are typically beyond the financial capacity of both rural and urban poor populations. To address this issue, various governments have initiated housing schemes aimed at facilitating homeownership for low-income groups. Given the limited financial resources in these countries, it is essential to explore ways to reduce construction costs, particularly for low-income populations, while adopting simple and efficient solutions for repairs and maintenance. This can be partially achieved through the production and use of inexpensive yet durable locally available building materials. In Uganda, various traditional construction materials have proven to be suitable for a wide range of buildings, offering significant potential for increased future usage.
Soil, for instance, is a key material used in constructing traditional low-cost dwellings in Uganda. It is well-suited to local weather conditions and occupancy patterns. In fact, soil construction methods are used in 80% of urban buildings in Uganda, with this figure exceeding 90% in rural areas. Buildings are constructed entirely, or partially, of soil, depending on factors such as location, climate, available skills, costs, building use, and local traditions.
Challenges in providing adequate and affordable housing for low-income populations are often tied to issues related to construction materials and technology. Research indicates that materials account for the largest single input in housing construction, representing 60-70% of total costs in Ghana (Danso & Manu, 2017), approximately 65% in Nigeria (Mogbo, 2017), over 76% in Tanzania (Wells et al., 2017), and 68% in Kenya (Syagga, 1993). Several scholars have established that the rising cost of building materials is a significant factor contributing to the widening gap between the demand and supply of affordable housing (Adedeji, 2007; Zami & Lee, 2010; Assaf et al., 2010; Kulkarni et al., 2014). In recent years, double-digit inflation in the price of construction materials has led to continuous increases in housing costs in certain countries (Adegun & Adedeji, 2017).
However, the issue of inadequate housing is not solely due to rising prices. The environmental impact of construction materials and technologies also requires attention. The demand for housing, coupled with the investment opportunities that accompany urbanization, could lead to a doubling of greenhouse gas (GHG) emissions from construction activities by 2050 (UNEP/CIDB, 2009). Moreover, most of the resources needed for construction are non-renewable, further exacerbating environmental concerns. These challenges highlight the need to promote materials that reduce both construction costs and environmental impact.
Earthen construction materials, which have a long history in Africa (Fathy & Denyer, 2017), are among the most widely researched technologies in the search for economically and environmentally sustainable housing solutions (Dayaratne, 2011). Despite their advantages and disadvantages, these materials have not been sufficiently understood, documented, or regulated, which hampers effective knowledge-sharing within Sub-Saharan Africa. The benefits of earthen materials have not been fully explored due to a lack of comprehensive research and aggregated empirical evidence. This gap motivates a review of existing literature to better understand the cost, energy efficiency, and thermal properties of earthen construction materials.
This review aims to foster greater interest in earthen materials and technologies for housing projects in African cities. Indigenous building materials like earthen construction methods fall into four broad categories: simple clay (adobe) blocks, rammed earth, clay/soil combined with other components, and machined blocks. Rammed earth construction, in particular, has been practiced for thousands of years, dating back to ancient China. Excavations have uncovered rammed earth structures from the 7th century B.C., including parts of the Great Wall of China, and the technique was later adopted in Europe and the Americas.
Rammed earth is a construction method that utilizes compacted soil to create thick, durable walls that are load-bearing, low-cost, heat-storing, and recyclable. This technique has been used independently in various regions of the world and is also known by its French name, “Pisé.” The method involves compacting soil between vertical formwork boards, which are later removed to reveal a solid wall. Rammed earth is often used in regions where the soil composition is unsuitable for making sun-dried clay bricks (Keable, 1994; Easton, 1996).
In modern times, rammed earth has been recognized as a sustainable construction technique that uses local materials. Since the 1970s, it has gained popularity in Europe and the United States as an environmentally friendly alternative to traditional construction materials. The method’s strength and durability have been enhanced through the addition of cement, rebar, and pneumatic compaction, although manual compression is still used in some rural areas, particularly in the tropics, where laterite soils are abundant.
In Uganda, rammed earth construction is not yet widespread, but it offers an attractive, sustainable alternative to traditional burned clay bricks, especially in areas with suitable soil. Recent applications of rammed earth construction have highlighted its aesthetic appeal, with builders layering different colors of soil to create visually striking structures.
Despite its long history, rammed earth has not changed significantly as a building method, although modern techniques have improved its strength and environmental impact. As the global demand for housing continues to rise, so too does the need for sustainable construction materials. The world’s cement market, currently standing at approximately 2 million tonnes, is largely consumed by emerging countries like Uganda. Given the increasing cost of traditional materials such as cement and granite, and the environmental challenges posed by their production, this research seeks to provide a comparative analysis of rammed earth and traditional burned clay bricks.
Historically, earth construction was prevalent in Kenya, where it reflected the architectural traditions of local communities. However, during the colonial period, earth construction was largely abandoned in favor of industrialized materials such as natural stone, glass, concrete, and ceramic tiles. Today, many people still favor these industrialized materials because they are perceived as fashionable and modern, even though they are often expensive, unsustainable, and ill-suited to the local climate.
This research underscores the importance of contemporary earth construction as a viable solution for affordable, sustainable housing. While rammed earth offers many advantages, further research is needed to fully understand its potential, particularly in terms of strength, durability, and environmental impact. By comparing rammed earth with traditional burned clay bricks, this study aims to provide insights into how earth construction can help meet housing demands in developing countries like Uganda.
