Desk Research & Primary Findings

Issued on: 30th August 2023

Table Of Contents

1. Background

1.2. Overview of Compressed Earth Blocks

Compressed Earth Blocks (CEBs) are a natural infusion of modern technology with one of the earliest elements of man-made structures: the mud brick or adobe block (Bowen 2017). They are essentially moulded adobe blocks produced using mechanical compaction. According to Earth Building and Association of Australia (2022), making CEBs requires dampening the earth and mechanically pressing it along with some sand and a small amount of aggregate binder such as cement at high pressure in a mould, and then setting aside the produced bricks to dry naturally. Studies show that compacted earth has been used before written history, so the utilisation of earth in housing construction is one of the oldest methods used around the world.

Some developing countries are no exception to the adoption and use of CEBs. According to Finnan (2018), the CEB method for construction is not only implemented in Gambia (see figure 1), but also in other African countries such as Burkina Faso, Ghana, and Nigeria as well as Sudan. According to Adam and Agib (2001), various traditional materials have proved to be suitable for a wide range of buildings and have a great potential for increased use in the future, including CEB (See Figure 2). In South Africa, the use of CEBs is gaining popularity. Moreover, Agrément South Africa (2016) has approved the CEB Building system for single-storey buildings.

The production of various types of soil bricks, such as adobe, mud bricks, and fired bricks, is quite prevalent in Lesotho, however, CEB has not been used due to a lack of knowledge (Adam and Agib, 2001). As a result, there is a pressing need for research to be conducted on this particular building material.

1.3. Advantages of Compressed Earth Blocks

From an architectural perspective, Compressed Earth Blocks offer similar form and functional qualities as brick, stone, and other masonry units. Moreover, they are more easily produced than stone and are more durable. Furthermore, the structural integrity of the material allows it to be used as a structural wall system that requires minimal reinforcement or additional framing (Bowen 2017).

The capacity of the material to absorb and radiate solar energy as heat is also one of its great advantages (Bowen 2017). This capacity can be termed ‘thermal buffering.’ This means that the material will absorb heat when it is cooler than its surroundings and re-radiate it when it is warmer than the surroundings. The energy-saving effect of thermal buffering is most marked by reducing the need for cooling, but it also has a comforting comfort effect because it reduces internal temperature swings (Bowen 2017).

The materials that go into making CEBs mostly come from nature. There is a reduction in chemicals that are used in the making of these blocks, therefore the material releases no harmful or toxic gas ( Happoadmin, 2022).

The usage of cement (usually about 4-10% of the soil and sand mix depending on the soil composition) is lesser and has the ability for on-site production, curing, and fixing, thus the cost reduction (Nnadi & Delunzu, 2022). According to Happoadmin (2022), CEBs are about 40% cheaper than conventional materials. Therefore, due to their thermal mass quality, CEBs can save anywhere between 10-15% on cooling and heating costs. Also, the time required to manufacture these blocks is minimal.

Manufacturing of CEBs can provide employment opportunities while inculcating social values in them. The compression machines can be powered or operated by hand, and do not require a lot of energy to produce like brick or concrete leading to low carbon emission (Happoadmin, 2022).

1.4. Disadvantages or limitations of Compressed Earth Blocks

When compressed earth block structures are exposed to prolonged weather conditions such as wind and water without proper roofing, they erode easily; however, adding stabilisers like cement improves the strength. Also, there is a time wait with the construction technique, because after the blocks are pressed, materials must dry; therefore the curing duration typically of 28 days also depends on the material used (pure earth with water, cement, or lime for stabilisation). Lastly, failure to mix soils correctly leads to weak blocks that crack easily (Bowen 2017).

2. Primary Explorative Research Findings

To collect primary data, snowballing, and stratified sampling were convenient sampling techniques for this study because it was imperative to select participants with first-hand knowledge about compressed earth bricks from a wide range of professionals and experts who have worked or are working on producing compressed earth bricks. This chapter presents the findings from one face-to-face, 3 calls, and seven Zoom interviews that lasted between 45 minutes to an hour each held in January and February 2023. A set of questions (check Annex 2 questionnaires for CEB) which included open-ended questions, had been prepared with the aim of gathering information about some specific topics such as availability, accessibility, cost, durability, knowledge, and techniques around producing compressed earth bricks.

2.1. Knowledge and techniques used when building using Compressed Earth Bricks

It was crucial to collect information from individuals who possess direct experience in producing Compressed Earth Bricks outside of Lesotho, as there is limited expertise within the country regarding both the production process and the specific machinery involved. All eleven respondents emphasised similar techniques, such as creating a dry mix of suitable soils with water and a small portion of cement for stabilisation. Respondents emphasised that surface soil isn’t utilised due to its organic content for gardening; instead, subsurface soil is preferred. Respondents stated that samples are examined to verify the accurate percentage of components, with a special focus on clay percentage, which can lead to significant expansion and cracking. Additionally, it’s important to assess the presence of rocks in the soil. Similar to clay, these rocks can also lead to cracks and gaps in the blocks. Respondents also indicated that cement is employed for mix stabilisation. The typical cement-to-earth ratio is around 10:90, which strengthens and stabilises the Earth Blocks.

Respondents stated that the strength of CEBs primarily derives from the pressure applied during production. Even with a lower cement content, such as 5% (5:95), it can yield a 7 MPA earth block, matching the compression rating of an inexpensive cement block. Respondents also described the production process using either a manually operated or diesel-powered compressed earth machine, which can be compact and portable. Finally, a machine can also be designed to produce 3 / 4 blocks simultaneously (see video CEB) The last important step Respondents mentioned about the production was the curing period which takes 28 days before being able to be used to build while placing it in the sun.

2.2. Costs and accessibility

Five respondents highlighted the cost-effectiveness of producing CEBs.This is attributed to on-site production, where the soil is readily available and cement usage is minimal compared to conventional bricks. Moreover, basic mechanical machinery for lower-scale production is relatively inexpensive.

One of the respondents indicated large-scale production costs required an outlay of M66 7049 (EUR 33,352) for machinery such as AECT Impact 2001 – a CEB Machine (see Figure 3). However, in the long run, these are offset by fairly cheap operational costs for energy and raw material consumption and usage.

2.3. Environmental Impact of Compressed Earth Blocks

Another key aspect we needed to grasp in our research was the carbon emitted during production and the overall impact of soil extraction. All eleven Respondents confirmed that Compressed Earth Blocks are less harmful to the environment compared to traditional materials. Specifically, producing CEB leads to fewer emissions and significantly less cement/lime per brick. Respondents pointed out that decreasing cement usage results in a significant  50% reduction in embodied carbon emissions. Additionally, Respondents emphasised that producing Compressed Earth Blocks provides a compelling opportunity to utilise earth extracted and processed directly at the construction site.

This offers a notable advantage compared to other materials in that earth is abundant throughout Lesotho, it reduces transportation costs, minimises transport-related pollution, and provides a solution for the displaced earth that is excavated on construction sites.

2.3. Durability of Compressed Earth Blocks

All eleven respondents affirmed that once cured for 28 days, CEBs exhibit durability. They noted that the material’s quality and solidity increase progressively, resulting in buildings that are recognized to endure for over 60 years. However, no compressive strength data was provided by the respondents to determine the optimal earth-to-cement ratio in terms of cost-effectiveness. This ratio varies based on the soil composition and clay content, which differ between sites.

3. Feasibility of Compressed Earth Blocks

There is an industry for earth-based bricks such as Fired bricks,& loti bricks (see Figures 4a, 4b, and 4c) which in Lesotho are manufactured formally in a factory called Loti Bricks as well as provided informally by artisans who create their furnaces on the roadside, against which we can discuss the feasibility of CEBs. This means that the policy framework for the production of CEBs currently exists which makes it viable as an enterprise. The difference in production processes skews the advantage towards CEBs because of lower emissions and fewer materials with embodied carbon (lime & cement). Lastly, there are no speed skills required in the production of CEBs which makes for relatively affordable and accessible labour requirements.

4. Distribution of Compressed Earth Blocks

The distribution of CEBs is tied to two main factors; accessibility of machinery and earth. For an industrial plant, it will be difficult to move the machinery to the building site, unlike the more compact mobile systems, which do not require transportation and warehousing. Since warehousing and transportation for alternative building materials are well developed in Lesotho, CEB companies can piggyback on these systems to distribute their products all over the country.

5. Unmet needs of Compressed Earth Blocks

The CEB market is untapped despite a history of other earth bricks, for instance, adobe bricks, in Lesotho. The oldest buildings in Lesotho are built from adobe and date as far back as 1843. However, there is no record of compressed earth buildings that we could find in Lesotho, although there is a growing interest in the production and use of this technology, one local artisan has made his own CEB machine (see Figure 5).

6. Conclusion of Compressed Earth Block

From an economic standpoint, there are a few factors that this paper has outlined that are critical to the development of a CEB-based industry. The first is that we do not have price-per-brick data that we can use in comparison with conventional materials to come up with a cost-per-square-meter standard. It is possible to project that, after the initial capital expenditure into the machinery, the material and labour operational expenses are fairly lower than competing fire bricks. There is a less labour-intensive process, a passive curing process, and the potential for on-site production which projects for a cheaper product. Overall, our analysis points to an economically viable option  that will yield a whole set of new jobs, complementary businesses, and alternatives to highly processed conventional materials.

The environmental impact of producing and using CEBs requires some thoughtful analysis since there are aspects of embodied energy and impact offset by some relatively cleaner and raw processes. The embodied energy is in the cement (when and if required) to enhance the compressive strength and durability of CEBs as well as the associated energy required to operate the diesel-operated machinery, though there is also CEB machinery available that is manually operated. However, these costs to the environment are offset by CEBs requiring very few materials that are abundantly available across the country. There are also no toxins associated with the production of these bricks onsite.

The sociopolitical conditions forebear a high potential for the development of the CEB industry. All of the raw materials are unregulated and the process does not emit any toxins that would require further approval. Competing materials like fired bricks have created a context for digging earth for manufacturing bricks and created a marketplace for alternatives to cement blocks. The demand for these materials should not be an issue since CEBs can be seen as an alternative to fired bricks and adobe blocks which have been used for a long time in Lesotho.

7. Recommendations for Compressed Earth Blocks

Our classification of the audience for the potential of CEBs is in the state, development partners, and the private sector. To the state agencies and development partners in the green economy, this paper recommends that a rating system be developed( see Annex 1 Material Specification) to illustrate the environmental benefits of using CEBs above alternatives. Secondly, once this industry is developed, a levy on imports may be used to discourage direct competition for CEBs to curb the overall carbon footprint and cost of importing a building material we can produce locally.

Development partners include NGOs, academic institutions, and private donor institutions with an interest in the spectrum between the basic need for shelter to the development of industry. From a technical perspective, this paper recommends that in-depth research be conducted into the performance of CEBs to support their readiness for the market. With the support of NGOs and donors, better regulations may be placed on where and how to mine the earth used for CEBs and other similarly resourced bricks to ensure environmental security for future communities.

Lastly, the private sector will play a key role in maximising the benefits of CEBs’ use in construction at all levels of the industrial hierarchy. At the top level, advocacy for CEBs in line with job creation, environmental impact (positive and negative), and built industry value chain development needs the participation of influential individuals and associations (Private Sector Foundation of Lesotho and the Lesotho Chamber of Commerce and Industry). Investment into the industry from financial institutions is also key to the mobilisation of the use of CEBs through funding the required infrastructure, marketing, and labour.

Compressed Earth Blocks are economical, produce low-emissions, and are primarily locally producible building materials. They are a good alternative for low-cost housing since Adobe alternatives have been used in Lesotho in the past. There is an opportunity for the mass production of these blocks which in turn will generate manufacturing jobs. To raise awareness and create demand for this building material a highly visible and utilised demo building made from CEB should be built to train community members on how to make CEB and build with it and gauge the interest in the material once it’s known. The presses can then be left with communities as income-generating activities to make CEBs and sell them; in this way, the economy will circulate amongst the communities.

8. Appendix

9. Bibliography

Adam, E. A. & Agib, A. R.A. 2001. Compressed Stabilised Earth Block in South Sudan. https://unesdoc.unesco.org/ark:/48223/pf0000128236/PDF/128236eng.pdf.multi

Agrément South Africa .2016. 2011/397 (Amended December 2016): Compressed Earth Blocks Building System. https://agrement.co.za/active_certificate/2011-397-amended-december-2016-compressed-earth-blocks-building-system/

Arumala, J. O & Gondal, T. 2017. The Construction and Building Research Conference of the Royal Institution of Chartered Surveyors. https://www.rivendellvillage.org/Compressed_Earth_Building_Blocks.pdf.

Bowen, M. 2017. A Best Practices Manual for Using Compressed Earth Blocks in Sustainable Home Construction in Indian Country. https://www.huduser.gov/portal/sites/default/files/pdf/Compressed-Earth-Blocks.pdf

Building Impact Zero Network. 2017. Design and Build with Compressed Earth Blocks. https://www.bi0n.eu/our-work/1-design-and-build-with-compressed-earth-blocks

Contributing Writer. 2012. BENEFITS OF COMPRESSED EARTH BLOCKS: Interview with Dan Powell of EarthTek. https://greenbuildingcanada.ca/2012/benefits-compressed-earth-blocks-dan-powell-earthtek/

Earth Building Association of Australia. 2022. Earth Building. https://www.ebaa.asn.au/about/earth-building/

Finnan, D. 2018. Innovative Compressed Earth Bricks boost Gambia’s construction industry. https://www.rfi.fr/en/africa/20180727-innovative-compressed-earth-bricks-boost-gambias-construction-industry

Guillaud H, Odul P, & Joffroy T. 1995. Compressed Earth Blocks: Manual of design and construction. Volume II. Hoehl-Druck, Bad Hersfeld. Germany

Happoadmin. 2022. Compressed Stabilised Earth Blocks (CSEB) – an alternative to Clay Bricks. https://happho.com/compressed-stabilised-earth-blocks-alternative-clay-bricks/

MecoConcept. 2022. Compressed Earth Blocks. https://www.mecoconcept.com/en/green-building/compressed-earth-blocks/

Nnadi, E.O.E, & Delunzu, V.U. 2022. Cost- Cost-benefit analysis of Using Stabilized Earth Block to Conventional Block Use in Housing Construction. https://www.irejournals.com/formatedpaper/1703280.pdf

Taos. 2023. Taos Pueblo. https://taos.org/explore/landmarks/taos-pueblo/

Desk Research & Primary Findings

Issued on: 30 August 2023

Table of Contents

1. Background

1.1 Overview of Straw and Grass as a Building Material

Grassland vegetation has dominated Lesotho’s landscape for the last 23,000 years or more, as documented by Oppong 2008. However, over time Lesotho’s grasslands have been substantially transformed by human activities to provide shelter and insulation before industrialised roofing and brick materials were introduced, according to Oppong (2008). Grass and straw have been used since the early 1600s for roofing and to build walls by mixing clay with cereal straw or grass and laid up on top of one another into a free-standing wall. Today the materials are most commonly found in rural villages, lodges, guest houses, and historical buildings as a homage to traditional methods of building and roofing.

However, in recent years migration patterns within the country and outside have resulted in the material being replaced with modern alternatives such as metal roofing and concrete blocks especially in urban, peri-urban, and to a small extent in rural areas. The apparent shift from using the material has been due to the fact that grass and straw  is viewed as low-cost, and it is associated with traditional housing, mostly used by people in rural areas with little or no source of income to afford modern materials (Oppong, 2008).

According to Oppong (2008) although thatched roofs have been common in Lesotho since ancient times, in the present day, the lack of incorporation of thatch roofing and the use of compressed straw in a more modern architectural world to meet the housing needs in the country reduces the prospects for sustainable development.

2. Types of Straw and Grass used as a Building Material in Lesotho

In Lesotho, there are two varieties of grass suitable for roofing and insulation: cereal and natural/wild grass, found in different regions. Lesotho can be divided into four major ecological zones namely; the Highveld Grassland, Afromontane(foothills), Afroalpine(lowlands), and Senqu Valley, which are home to a variety of grasses and agricultural produce.

2.1. Cereal straw

Due to the unique climate and soil conditions in Lesotho, the most common cereal crops are maize, wheat, and sorghum which are the primary grains consumed locally. There are byproducts from the harvesting of these crops that can be incorporated into the built industry, particularly as roofing materials and for insulation. In Lesotho, wheat straws have been used for roofing, particularly in the highlands of Lesotho. This is due to the fact that highland districts such as Thaba-Tseka, Mokhotlong, Qacha, and Quthing were identified as the top-producing regions for straw in the country [1] (The Lesotho Vulnerability Assessment Committee’s Crop Estimates report for, 2022).

However, the introduction of compressed straw as an insulation material has not been instigated in Lesotho. The compressed straw buildings were first constructed in the late 1800s in Nebraska, USA with the development of steam-powered balers. Even in earlier days, walls made from either tired bundles of straw coated with clay or compacted loose straw mixed with clay have been constructed for centuries throughout Asia and Europe. With the growing awareness of the strong and risky effects on climate, the notion of both reducing carbon costs and carbon sequestration has led to the effective use of compressed straw as a building (Sarath, C & Kumar. B, 2012). Therefore, there is an opportunity to explore compressed straw as a possible building technique for contemporary building standards and preferences in Lesotho (See Figure 1 which shows compressed straw).

2.2. Wild grass

In Lesotho there are four different types of wild grass available that can be used for thatch: qokoa (Hyparrhenia tamba), mohlomo (Hyparrhenia hirta), tsaane (Eragrostis chloromelas), and lehlaka (Phragmites australis), available in different districts in different quantities (Kose, 2021). It is important to note that some of the naturally growing grasses, like qokoa and mohlomo, are legally protected and are prone to sociopolitical controls that may influence their availability for use in the built industry. Another important issue to note is that some of these grasses may be farmed, which again has an impact on the availability of the grass. These socio-political aspects of grass use in the building industry are explored in detail later in this paper (See Figure 2, which shows the Agro-ecological zone).

2.2.1. Highveld Grassland ( Lowlands)

This zone spans from the western lowlands of Lesotho starting at the lowest point (1400 m.a.s.l) which includes the Southern region of the Senqu Valley and extends to about 1800 m.a.s.l. Its main vegetation consists of grass species, the bulk of which are Hyparrhenia Hirka mohlomo and qokoa.

Mohlomo typically grows on mountains and between mountain slopes. According to the Ministry of Natural Resources World Wetlands Day report in 2004, mohlomo is considered to have the best quality among all types of wild grass for thatch in Lesotho, and its quality is comparable to that of thatch used in South Africa. It can last for 20 years or more (See Figure 3).

Qokoa, on the other hand, has larger stalks, is less durable, and rots more easily. It is also available in the northern parts of Lesotho

Tsaane is found in the Southern regions of Lesotho. It is characterised by short stalks which make it less durable because it allows water to penetrate in the house.

2.2.2 Afromontane Grassland Zone ( Foothills)

This zone ranges from 1800 m.a.s.l to around 2500 m.a.s.l in altitude. Geographically, it ranges from the upper Senqu Valley to the watershed, covering most of the Maloti Mountain range in the centre of the country. The foothills also include parts of the Drakensberg mountain range in the north as well as the eastern side of the Senqu Valley. It has a wide range of grasses mainly mohlomo and qokoa and it grows successfully due to the volcanic soil and warmer temperatures. They are a significant region for the natural growth of a variety of grasses that can be used in the built industry.

2.2.3 Wetlands Zones

The wetlands are mostly in the lowlands, particularly in the Districts of Berea and Maseru which is where water reed (Phragmites australis) commonly known as lehlaka can be found. It is a highly durable building material, lasting up to 20 years or more.

3. Application of Straw and Grass

Historically, a typical grass-thatched hut was constructed on a circular foundation dug into the ground. Long, flexible poles were inserted into the foundation (Mokorosi, 2017), as shown in Figure 4 with the top bent inwards and tied together to create a hemispherical shape. Thinner poles or split poles were woven in and out of the larger poles, and grass was used for thatching. The grass would usually extend to the ground, forming a beehive-like structure for the hut (Casalis, 1861; Dreyer, 1993; Mokorosi, 2017). Mud was sometimes applied to the outside of the huts as well (Casalis, 1861, See Figure 4)

In the 1900s, there was a shift away from grass-thatched huts to more durable materials such as stone, earth, and timber. These materials were all locally sourced, and water and cow dung were used as binders. Traditional huts began to feature stone foundations and walls, with thatch being used primarily as a roofing material (Mokorosi, 2017). During the 20th century, the most common traditional house type in Lesotho was the rondavel, which could be either circular or rectangular in plan (Anderson & Stovre, 1997; Liechti & Hill, 2019, See Figure 5a and 5b).

According to a report by New Media (2020), various techniques and equipment are employed when building with thatch, and specific dimensions and angles need to be followed when roofing with thatch. The report states that a thatched roof should have a minimum pitch of 45 degrees and a minimum of 35 degrees over dormer windows. To achieve a smoother thatched roof, the Thetho tool, also known as deskspa (Language used by Basotho thatchers), is used. The smoother the finish, the better the water will run from it, preventing leakages and prolonging the roof’s lifespan.

As per Premier Guarantee (2022), wild thatch is first placed in position and then raked to give it a “poured onto the roof” appearance. For new work, the overall thickness of natural thatch is 400mm, while cereal straw has a much neater and trimmed look. During installation, the thatcher dresses and knocks the thatch into shape, and the overall thickness for new cereal straw work ranges from 300-450mm (Premier Guarantee, 2022).

Additionally, straw and reed can be used for insulation by placing the materials directly onto the rafters in order to provide support and insulation for the corrugated iron roofing. While this material is most abundant in wet lowland areas, it has become increasingly scarce in recent years due to the degradation of wetlands, particularly in Koro-koro and Qalabane (Ministry of Natural Resources, World Wetlands Day, 2004) (See Figure 6).

4. Advantages of Straw and Grass as Building Material

According to Stronbach & Walter, 2022, building with straw and grass significantly reduces both embodied and operational carbon compared to construction with  conventional  materials due to the absence of energy required during its harvesting process. Also, straw stores CO2 which remains locked up in the structure of straw buildings. It is also thermally efficient, renewable, biodegradable, and readily available in Lesotho, particularly cereal straw and Mohlomo and Qokoa grasses.

In comparison to all other roofing materials such as metal sheets, thatch has a higher insulation value as can be seen in the Material Specification Table in Annex XX[1] . As a result, buildings with grass and straw walls are more thermally efficient, reducing the amount of energy required for heating during winter and cooling in summer. This not only benefits the environment but also provides economic benefits by reducing the consumption of fossil fuels such as paraffin and charcoal used for heating in Lesotho’s long and bitterly cold winters. The density of  compressed straw in construction influences the air gaps between the stalks and between the bales themselves and therefore the thermal conductivity efficiency. Compressed straws are high-performing insulators and experience minimal decomposition over time (Marlow, 2021).

5. Disadvantages of Straw and Grass as Building Material

Stronbach and Walter (2015) reported that grass and straw  are vulnerable to fire. Lightning strikes and open-flame cooking fires are often the culprits. In the absence of building standards about thatch in Lesotho, we referenced South Africa’s thatched roof construction law and standards (SANS 10407). It states that insurance premiums for grass and straw buildings are much more expensive than other roofing materials such as clay tiles, due to their vulnerability to catching fire which can also affect neighbouring buildings.

Additionally, Marlow (2021) pointed out that the quality of straw and grass is dependent on good weather during germination, cultivation, and harvest, which is often reliant on hard-to-find casual labour and old manual equipment. Consequently, harvesting and processing costs are increasing, and the quality of the grass and straw is often poor, necessitating the use of expensive thatch sealants. As a result, many building owners are turning to alternative materials, leading to a decline in demand for thatch roofing.

The issue of durability is another concern for thatch roofing, despite that a well-maintained thatched roof can last up to 20 years, which is comparable to or longer than other competing materials. However, due to improper drying, a lack of access to superior grass species, and possible termite infestation, many thatched roofs may require replacement more frequently than the expected lifespan of 20 years, leading to a shift towards corrugated iron as a cheaper and faster to install alternative. Additionally, thatch is vulnerable to damage from hail, further exacerbating problems with thatched roofing (Marlow, 2021).

6. Primary Explorative Research Findings

6.1 Research Methodology

To collect primary data, a stratified sampling technique was used based on different qualifying criteria which were all aligned with the number of years of experience from 10 years or more. The selection criteria of the interviewees were based on their qualifications, skills, and knowledge because it was imperative to select participants with a first-hand understanding of thatch from a wide range of occupations. The participants were not paid to take part in the interviews. A set of questions, (see here research questions on thatch)[2]  was prepared with the aim of gathering information about some specific topics such as availability, accessibility, cost, durability, and knowledge around construction techniques with thatch.

The chapter is divided by topic and summarises  the information  collected from the interviews, presenting the key findings. A total of  11 interviews with thatch experts and professionals have been conducted from January to June 2023; the researchers conducted face-to-face interviews, which lasted around 45 minutes each, to gain insights into people’s experiences, opinions, and facts about thatch in Lesotho. The respondents represented the entire spectrum of the thatch industry in Lesotho ranging from government officials through skilled professionals and built industry experts. On average our respondents had 24.5 years of experience ranging from 7 years to 41 years.

6.1.1. Availability of Grass & Straw in Lesotho

Seven of the Respondents confirmed our desk research findings that the different grasses in Lesotho can be found in the three ecological zones: Highveld Grassland, Afromontane Grassland, and Afro-alpine Grassland. The Respondents  stated that the availability of grass and straw is highly dependent on the season. The Respondents further stated that grasses are available in abundance during the Spring harvesting season when the grass is dry, while cereal straw is available in Winter, particularly in June and July.  Although the majority of respondents said that the three kinds of grass (Qokoa, Tsaane & Mohlomo) are available in abundance.

 Three of the respondents  opposed that viewpoint and claimed that both grass and cereal thatch are deteriorating in quality and quantity. The respondents further mentioned the changing climate, combined with insufficient management of this resource and land use, has resulted in the need to import thatch from South Africa particularly to build and maintain some of the historical buildings and lodges. Also,  respondents  indicated that, in recent years  the government has shifted from using grass as a roofing material to using modern building materials when building public infrastructure like the new museum.

Respondents also stated that overgrazing and deforestation have led to a reduction in the production of natural grass for thatch.

6.1.2. Cost of Grass and Straw in Lesotho

Our goal was also to understand the short and long-term costs of using grass and straw. These covered the purchase of the raw materials, the cost of labour, the ongoing cost of maintenance as well as any reduction in heating costs given the postulated thermal efficiency of thatch. Six of the Respondents, who are experts in roofing & ministries, indicated that the use of thatch is expensive in the short term due to the costs of labour and cost of material since grass is only available at no cost for the residing local communities and not to external parties residing outside of the communities. Additionally, Respondents further stated that the majority of the suppliers stockpile the material in order to raise the prices while also reducing the size of bundles.

In contradiction to our desk research which found that Lesotho’s quality of grass and straw matched South African standards,  two Respondents outlined that poor  quality material and lack of skilled labour in Lesotho to build large structures has resulted in the Ministry of Tourism importing these resources from South Africa to  build  the Thaba Bosiu cultural village. The Respondents indicated that the cost of labour sourced in Lesotho is expensive, costing  M400.00 (EUR 20)  per square metre.  Compared to metal or clay roofing which incurs labour costs of M45.00 (Euro 2.25)  per square metre respectively.

However, five of the Respondents argued that there are short-term and long-term benefits of using this material in that there are short-term benefits as the material is essentially cheap, costing M10.00 (Euro 0.50) per bundle. The Respondents further stated that the material is free for the suppliers residing in areas where the grass is available  because grassland is held communally. The use of resources is regulated by chiefs and village councils who allocate pieces of land, called ‘litema’, to individual households to harvest  for free. Additionally, the Respondents expressed that  buying the material from individual households who are the primary suppliers of the material in Lesotho makes the buying price  cheap mainly because a lot of suppliers are not formally employed, they have resorted to selling thatch as a way of supporting their families therefore the price is negotiable. The Respondents further outlined that because wheat is already being cultivated in the country each household can grow it, making it free. Furthermore, the Respondents indicated  that there are long-term benefits that involve an 80% reduction in the cost of heating materials due to their thermal efficiency.

6.1.3. Quality & Durability of Grass and Straw in Lesotho

Eleven  of the Respondents explained that the different types of grass have different qualities and characteristics that affect the lifespan and maintenance of thatched roofs and insulation. The respondents stated that in the previous years, Mohlomo was considered to be the best quality among the different types of grass with an expected lifespan of about 20 years without requiring any maintenance. However, the eleven Respondents expressed that in recent years the quality of Mohlomo  has deteriorated and needs maintenance after approximately 3 to 5 years due to the poor quality of grass species and the harsh weather conditions. Respondents also articulated that cereal straw is also no exception as the amount of yield and quality have decreased meaning that regular maintenance of roofing is needed every 8 months or so. The Respondents asserted that the  quality of  Qokoa and Tsaane has also been negatively affected by changing climatic conditions and land degradation.

To address this, Respondents declared that modern materials like thatch sealer (a solution that has to be sprayed on both sides of the thatch to prevent moisture from entering into the structure) have been used to improve its longevity, but it comes at a high cost of M4,000 (EUR200) for 20 litres which is the amount that is needed for a typical standard size rondavel.

6.2 Knowledge and Techniques of Grass and Straw in Lesotho

All of the eleven Respondents indicated that there is a shortage of skilled thatchers and that the trade is dying out. Additionally, the Respondents further showed that due to the informal nature of these artisans, little information exists on the availability of skilled thatchers, and there is no database or Trade Association, or formal entity for thatchers.  Also, the Respondents made further indications that the new generation shows little interest in learning this technique. The Respondents further confirmed that the lack of or no skilled labour capable of roofing large structures results in skilled thatchers being sourced from South Africa. Therefore, a list of skilled Thatchers’ is needed to help formalise the sector and encourage young people to take up the thatching trade within the built environment by providing it as a trade in the vocational and technical schools.

7. Feasibility of Grass and Straw

Lesotho’s thatch market is highly dependent on the demand  for cultural and tourism-related buildings such as lodges and restaurants which contribute highly to the economy and to the preservation of  Basotho’s culture. However, skilled thatchers are scarce and overly expensive if you find one, making it a costly material in the short term that is not available throughout the year and production is highly susceptible to climatic change.

8. Distribution Patterns of Grass and Straw

Community members are the primary distributors of thatch; as mentioned above they are given rights by the Chief as the land is held communally in the country and regulated by them. It’s usually sold informally on demand when someone needs it, and not sold in any markets or hardware stores.

It is not a fragile material, hence it is easy to transport and does not require special packaging. When stored properly, thatch can last for a long time without going rotten.

Distribution patterns depend on policymakers and decision-makers as  areas where it’s available need to be mapped out, and regulations on who can have access to the land on which it grows need to be developed before it can be distributed to the public on a large scale.

9. Unmet needs of Grass and Straws in Lesotho

The main unmet need regarding the grass and reeds for thatch is the lack of documented information about the location of natural thatch resources (such as water reeds and wild grass for thatch), which makes it challenging to determine their availability in the country.

Furthermore, the traditional knowledge and techniques used in thatch roofing are often not recorded and are only known by a small group of elderly community members. Unfortunately, some of these skilled thatchers pass away without transferring their knowledge to the younger generation, making these techniques even more scarce.

10. Conclusion

The fact that the grass for thatch is not readily available to the mass market, and thatchers are not recognized as a formal profession, thatch remains a cottage artisanal industry in Lesotho. The decrease in the use of thatch for roofing and insulation has led to an increase in the use of modern building materials that are not sustainable: economically, environmentally, and socially. This is because of the notion that thatch is not available in the country due to no mapped-out areas showing its availability and accessibility.

Additionally, the lack of a documented list of  skilled personnel with knowledge of the material has contributed to the shift away from using this material. However, thatch roofing and straw insulation as well as compressed straw bales offer plausible alternative solutions in the development of sustainable housing in Lesotho to meet the outstanding housing needs. Hence, there is a need to revive this material to promote its thermal efficiency, which results in an 80% reduction of costs in heating and cooling and also lower carbon emissions from the extraction process and the use of the material.

11. Recommendations

It is important for the government and other relevant stakeholders to conduct a comprehensive survey to document the knowledge and techniques applied when roofing with thatch, map out the areas of availability and accessibility of natural grass for thatch, and provide training and formalisation of the skillset of thatch. This will not only preserve this valuable cultural heritage but also create job opportunities, promote the use of sustainable and locally available materials, and contribute to Lesotho’s efforts to reduce carbon emissions by lowering the use of alternative heating fuels due to the thermal efficiency of the material. Also, little or no energy is used when harvesting and building using the material. Furthermore, there is a need for advocacy and awareness-raising campaigns to promote the use of thatch as a roofing and insulation material in urban, rural, and peri-urban areas and its benefits to the environment and the economy.

In addition to mapping out areas where thatch is available, it would also be important to create a database of skilled thatchers to preserve and pass on their knowledge to future generations. This could be done through apprenticeships, training programs that can last up to 8 weeks, and certification courses, which would provide a path to formalise the skillset and make it a viable career option for younger people. By promoting the use of thatch as a sustainable and cost-effective roofing material in the long run, and providing the necessary support and resources for its cultivation and preservation, the country can create a thriving industry that benefits both the economy and the environment.

Different approaches need to be adhered to in order to lower the cost of using the material through preservation and exchange of skills which will help lower the need to hire external labour outside of the country and to import thatch while also leading to the abundance of the material through improved conservation majors.

12. Appendix

Appendix A: Table of Respondents

13. BIBLIOGRAPHY

 Ashour, T. &  Wu, W. 2011. Using Barley Straws as Building Material. https://www.researchgate.net/publication/287478964_Using_barley_straw_as_building_material

Casalis, E., A., 1861. The Basutos. J. Nisbet. Retrieved from: https://doi.org/10.5479/sil.262374.39088000167106

 Chen, J. Elbashiry, E. &  Yu, T. 2017. Research progress of wheat straw and rice straw cement-based building materials in China https://www.researchgate.net/publication/318480337_Research_progress_of_wheat_straw_and_rice_straw_cement-based_building_materials_in_China

Dreyer, J. 1993. The Basotho hut: From Late Iron Age to the present. South African Journal of Ethnology, 16(3) https://journals.co.za/doi/pdf/10.10520/AJA02580144_730

 Lesotho Vulnerability Assessment Committee Crop Estimates, 2022. https://drmims.sadc.int/en/organizations/lesotho-vulnerability-assessment-committee-lvac

 Marlow, C. 2021. Traditional Straw Thatching in Time of  Shortage. https://historicengland.org.uk/content/docs/advice/traditional-straw-thatching-times-of-shortage-context167-mar21/

Ministry of Natural Resource, 2004. World Wetlands Day. https://www.ramsar.org/news/world-wetlands-day-2004-lesotho

 Mokorosi, S. A. 2017. Basotho Traditions: Indigenous Architecture and Creativity. Morija Printing Works. https://searchworks.stanford.edu/view/13170501

Oppong, R. 2008. A Trio Sub- Saharan African Compendium: “Losing the sense of thatch” http://dev.ecoguineafoundation.com/uploads/5/4/1/5/5415260/thatched_roofs.pdf

Premium Guarantee, 2022. Thatched Roofing: Interaction with Modern Construction Techniques. https://www.premierguarantee.com/our-services/structural-warranties/

Stronbach, B. & Walters, W. 2015. An overview of grass species used for thatching in the Zambezi, Kavango East, and Kavango West Regions, Namibia. researchgate.net/publication/286447092_An_overview_of_grass_species_used_for_thatching_in_the_Zambezi_Kavango_East_and_Kavango_West_Regions_Namibia

Desk Research & Primary Findings

Issued on: 30th August 2023

1. Background

1.1. Overview of Wool

Baumgartner (2021) explains that Lesotho has a rich history and tradition in its wool industry, with high-quality wool produced by the nation’s sheep since the 1800s. The industry has a well-established network that connects local producers with brokers in South Africa who purchase the raw product for processing and sale. According to Forrester (2021), wool is the backbone of Lesotho’s rural economy, with producers ranging from smallholder farmers to breeders of large flocks with superior genes. Currently, there are over 1.2 million sheep with a significant potential for industry development. On average, one sheep produces nearly three kilograms of wool annually. Primarily, Lesotho exports raw wool to warehouses in Port Elizabeth, South Africa for grading and processing for readiness for the international market. 80% of the wool is the exported to China, while the remaining 20% is exported to European countries labeled as South African wool, along with South African wool (The Reporter Newspaper, September 22, 2022).

The observation was that wool is currently not utilised for insulation in buildings in Lesotho. According to the International Wool and Textile Organisation (2020), wool has diverse uses, which depend on the coarseness of the fiber and its other characteristics, including fiber length and crimp. Besides widespread use in the textile industry, there is an opportunity to use the insulation properties of wool in buildings which necessitated this research into the viability of the use of wool, in particular the lower grades of wool that are less attractive for the textile industry, and can be used as an insulation material in construction industry instead (The International Wool and Textile Organisation, 2020).

1.2. Wool as a building material

According to Renz (2022), wool has become increasingly significant in the construction industry due to its many natural properties. According to SANS 10400, XA building towards more sustainable and less resource-intensive building practices will reduce energy consumption. The goal is for all new residential and commercial buildings to contribute an estimated 3,500 MW of electricity savings. As nature has often inspired technological innovation and intelligent design, sheep wool is now at the forefront of these advancements (Renz, 2022). Renz (2022) further adds that the rising popularity of wool as an insulation material in construction is due to increased awareness regarding the health benefits and performance of natural fiber insulation. The thermal insulation is typically measured by its thermal resistance often referred to as the  R-value which determines the type of insulation that is required. According to SANS 10400 XA, Lesotho’s climate  requires a minimum R-value of 3.7 for insulation purposes. This would support the cause for effective insulators such as sheep wool. The table in Annex 1 Material Specification relays a comparison of wool’s thermal performance against other conventional materials.

This research explores the possibility of using wool as a brick and an insulating material in Lesotho, looking at its availability, durability, cost, and thermal efficiency

1.3. Wool bricks

Fecyt (2010) reports that researchers from Spain and Scotland conducted a study on the use of sheep wool in various composite materials, such as adobe bricks and cement mortar, and made several significant findings. The research revealed that wool fibers can enhance the strength of compressed earth bricks, decrease the occurrence of fissures and deformities due to contraction, reduce the bricks’ drying time, and increase their resistance to flexion (refer to Figure 1). Remarkably, these wool bricks can be produced without firing, resulting in energy conservation. Also,  bricks are considered a sustainable and healthy alternative to conventional building materials, which is why wool bricks are gaining more attention in research (Fecyt, 2010).

2. The advantages of Wool

Wool is a sustainable and renewable material that is also natural. It does not cause any harm to human health and is non-irritating to the eyes, skin, or lungs. Unlike rock wool or fiberglass wool, which is hazardous to install, wool fibers are much safer to handle. Wool is breathable and can absorb and release moisture without compromising its thermal performance, making it ideal for insulation (Denes, Manea & Florea, 2019). Additionally, wool is fire-resistant and can extinguish itself in the event of a fire. It can also absorb volatile organic compounds (VOCs) from the environment, making it an excellent choice for indoor air quality. Wool is static-resistant and does not attract lint and dust, making it resistant to dirt. It is an effective insulation material for both thermal and acoustic purposes, as it absorbs noise and reduces noise levels. When wool fibers absorb moisture, they generate heat, which helps to prevent condensation in structures and minimize the risk of mold and mildew formation (Denes, Manea, & Florea, 2019).

A sustainable and renewable material, sheep’s wool insulation has no adverse impact on the environment. It boasts an R-value of approximately 3.5 to 3.8 per inch of material thickness, which is 0.3 to 0.6 points higher than fiberglass, cellulose, or mineral wool. A higher R-value indicates that a material is more effective at resisting the flow of heat (Denes, Manea & Florea, 2019).

Sheep’s wool insulation is a versatile and eco-friendly option available in various sizes and thicknesses, including slabs, batts, and rolls. It is a completely natural product that requires 15% less energy to manufacture compared to glass wool insulation, making it more sustainable. Thanks to its high nitrogen content, sheep’s wool is one of the few fibers that are naturally flame-resistant and self-extinguishing. Instead of igniting, it will simply smolder and singe away, reducing the risk of fire (Denes, Manea & Florea, 2019).

3. Disadvantages of Wool

The installation of sheep’s wool insulation can be costly. For example, in Europe, it can cost approximately €62 (equivalent to M1240) per square meter to achieve the recommended thickness of 300mm. This is considerably more expensive than mineral insulation, which costs around €17 (M340) per square meter (Tiza, Singhs, Kumar & Shetta, 2021). Another disadvantage of wool insulation is related to its cleaning and preparation process. To make it effective and suitable for use, wool must undergo treatment and cleaning that involves the use of harsh chemicals for disinfection and to address possible scab mite infestations (Tiza, Singhs, Kumar & Shetta, 2021).

4. Primary Explorative Research Findings

To collect primary data, snowballing was a suitable sampling technique for this study, because it was imperative to select participants with first-hand knowledge about wool from a wide range of participants. This chapter presents the findings from the face-to-face interviews that lasted between 45 minutes to an hour each held in January and February 2023, undertaken with professionals who work with wool. A set of questions, (see Annex 4 questionnaires wool) had been prepared with the aim of gathering information about some specific topics such as availability, accessibility, and cost of using wool as an insulating material. With regards to wool, we only had one interview which was with  the Wool and Mohair Association. This was because the Association is the central selling point of wool where it’s all collected from all 10 districts and they have information about the different grades of the material in the country and the amount collected yearly and sold.

4.1. Availability of Wool

The purpose of this exercise was to know where wool is available in the country and in what quantity and  to know the season of shearing and the quantity of wool sheared. Ten  Respondents (Wool and Mohair Association) revealed that the shearers are divided into government shearing sheds, estimated at around 155 sheds, and privately owned shearing sheds around 80+ in different districts. The respondents further indicated that in the Maseru district only there are 21 privately owned shearing companies which indicates an abundance of wool in the country. The Respondents further claimed that the amount of wool sheared in the country increases every year due to the rising reproduction of sheep, with farms in the Districts of Mokhotlong and Quthing producing the highest amount of high-quality wool. The Respondents stated that in 2020/21, the amount of wool collected was 1,000,283kgs and in 2021/22 the amount quadrupled to 4,379,590kgs.

Seven of the Respondents claimed that low-grade wool is not exported because there is no market for it abroad. As a result, it is sometimes disposed of as waste. Others said that low-grade wool is sold locally through the informal market by the roadside, mostly during the shearing months of August to December.

Three of the Respondents (supervisors of shearing companies  stated that as much as wool is available in abundance all the wool is sold and exported to already existing clients. They added that low-grade wool (for instance, black wool) is still sold to international markets such as China, where the value fluctuates around M70/kg (EUR 3.50) depending on the market.

4.2. Cost of Wool

Ten Respondents confirmed that there are 41 different grades of wool. Each has its own selling price, ranging from approximately M70/kg (EUR 3.50) for low-grade wool to M510/kg (EUR 25.50) for high-grade wool. The Respondents further claimed that the most expensive wool is lamb’s wool due to its softness. Other factors that influence the price include length, tenderness, and microns (measurement of the diameter of wool fiber).

5. Feasibility and Viability

Wool is Lesotho’s leading agricultural commodity export. And yet, the market has not introduced the utilization of wool as an insulation material, because most of the wool produced in Lesotho is auctioned and brokered to the South African textile industry. However, there is a quantity of low-quality wool that remains unexported. The exact amount of this unexported wool is unknown. Thus the question of the possibility of wool being a feasible and viable material for the local construction industry remains unanswered.

6. Distribution patterns

Wool already follows a certain chain of supply in the country from local to international market making it difficult to open up different distribution patterns from the one that’s already existing. Also due to its scarcity, it is not deemed profitable to join a different supply chain.

7. Unmet needs

Lesotho’s wool is exported because there are no manufacturing industries to process wool in the country. The exportation of Lesotho wool into South Africa means that the potential taxation and other economic benefits such as processing wool and mohair in Lesotho are lost to South Africa. Besides that, research into sheep wool as a building material in Lesotho has not been explored, meaning that the market of wool in construction does not have facts supporting its establishment.

8. Conclusion

When assessing wool as a potential resource in the built industry in Lesotho, it is important to consider the following factors: distribution patterns, development and marketing of wool in the built industry, wool harvesting innovations (from shearing of wool and standard separation of wool) cost and the availability of the material. Moreover, it seems as though there is a high potential for increased wool production in Lesotho with endless job opportunities and circulation of money within the country. The serendipity of pursuing this is expansion and growth in the built industry which will have long-term benefits to the environment.

Using wool in construction is not only good for the environment, but has the potential to bring a paradigm shift in Lesotho’s architectural landscape. Wool presents a green alternative to use as an insulation material which will result in the reduction of operational costs in the long run. We also need to emphasize the health benefits of working with and living in wool-insulated houses over alternatives like rock wool and fiberglass. However, the unavailability and high cost of buying both high and low-grade wool and an already existing market with different international countries, hinder the use of wool as an insulation material in the country.

9. Recommendations

We recommend that deeper insight into the wool data be established to determine the amount of low-grade wool that is available because it is currently unknown and to highlight the economic benefits of using it in the built industry. Since there is a well-established competing textile industry, we can focus on poorer grades which are known to be ignored by the export industry. To get wool and have ownership rights to the wool produced in Lesotho; establishing a wool testing laboratory in Lesotho will serve as an important step towards providing sampling and testing services in Lesotho. This will therefore encourage Lesotho wool and mohair farmers to sell locally. The initiative will ensure that a greater portion of wool and mohair products are produced and processed in Lesotho and a possibility of wool residue collection obtained during processing, before being exported. This will also encourage an increase in sheep husbandry that is relatively widespread in Lesotho, resulting in a wool increase. This will also serve as an entry point to the possibility of using wool for construction purposes. While the health and environmental benefits of using wool as a building material have been stated, it is important to place it in the context of conventional alternatives. Our regulatory bodies do not currently enforce the use, or banning, of alternatives such as fiberglass. This paper and follow-up discussion will create a platform from which the public can be informed of better materials for their homes and offices. This renewable resource is part of a larger food security value chain and it is recommended that the agribusiness sector is approached for collaborative exploration into these mutual benefits.

10. Appendices

Appendix A: Table of Respondents

11. Bibliography

Baumgartner, P. (2022). Finding a way forward: Sector reforms in Lesotho’s wool and mohair industry. https://www.ifad.org/en/web/latest/-/finding-a-way-forward-sector-reforms-in-lesotho-s-wool-and-mohair-industry. Retrieved 09/12/2022

Denes, O., Florea, I., & Manea D. L. (2019). Utilization of sheep wool as a building material. https://www.researchgate.net/publication/332595258_Utilization_of_Sheep_Wool_as_a_Building_Material. (Accessed: 12/12/2022)

FECYT – Spanish Foundation for Science and Technology (2010). Bricks made with wool. https://www.k-online.com/en/Media_News/News/Bricks_made_with_wool

Forrester, N. 2021. The Magic of Wool in the built environment. https://archipro.co.nz/articles/building/the-magic-of-wool-in-the-built-environment-archipro-nz. (Accessed: 09/12/2022)

Global Market Estimates. 2022. Global Building Wool Insulation Market. https://www.globalmarketestimates.com/market-report/global-building-wool-insulation-market-2965. (Accessed:10/12/2022)

Home Logic: Solutions for Homes (2021). Sheep wool insulation Pros and Cons https://www.homelogic.co.uk/sheep-wool-insulation-pros-and-cons. (Accessed: 12/12/2022)

Innovative Applications in Architecture (2012). Material Strategies: Wool in Architecture. https://arch5541.wordpress.com/2012/11/25/wool-in-architecture/. (Accessed: 08/12/2022)

Korjenic A, Klarić, S, Hadžić A, Korjenic S. (2015). Energies: Sheep Wool as a Construction Material for Energy Efficiency Improvement. http://www.mdpi.com/journal/energies . (Accessed: 12/12/2022)

Renz, A. (2022). Sheep Wool Insulation: A Low Carbon Solution. https://buildersinsulation.co.uk/sheep-wool-insulation-a-low-carbon-solution/. (Accessed: 12/12/2022)

International Fund for Agricultural Development (2019). Spinning yarns – Investing in wool and mohair in Lesotho. https://www.ifad.org/en/web/latest/-/story/spinning-yarns-investing-in-wool-and-mohair-in-lesotho (Accessed: 10/12/2022)

International Wool and Textile Organisation (2022).Wool Notes. https://iwto.org/wp-content/uploads/2020/04/IWTO_Wool-Notes-Web-min.pdf (Accessed: 10/12/2022)

Legge,A.( 2018). A Smart, Natural Wool Insulation for Healthy Buildings. https://havelockwool.com/2018/04/a-smart-natural-wool-insulation-for-healthy-buildings/  (Accessed: 12/12/2022)

Manchee, L. (2020). Keela Permaculture Farm: Cleaning and Using Sheep Wool for Insulation. https://www.keelayogafarm.com/2020/07/29/cleaning-and-using-sheep-wool-for-insulation/ (Accessed: 12/12/2022)

Remi Network (2017). Sheep’s wool insulation is seen as a sustainable option. https://www.reminetwork.com/articles/sheeps-wool-renewable-sustainable-building-insulation/ (Accessed: 08/12/2022)

Romania Insider (2019). Agriculture minister says RO will see first wool-insulated houses this year. https://www.romania-insider.com/agriculture-minister-says-ro-will-see-first-wool-insulated-houses-this-year. (Accessed: 12/12/2022)

ScienceDaily (2010). Bricks Made with Wool. https://www.sciencedaily.com/releases/2010/10/101005085503.htm. (Accessed: 09/12/2022)

The Reporter Newspaper (2022). Lesotho wool cleared for sale to China. https://www.thereporter.co.ls/2022/09/22/lesotho-wool-cleared-for-sale-to-china .(Accessed: 10/12/2022)

Tiza, T. S., Singhs, S., Kumar, L. & Shetta, M. Assessing the Potential of Bamboo and Sheep Wool Fibres as Sustainable Construction Materials: A review https://www.sciencedirect.com/science/article/abs/pii/S221478532103916X