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Drivers that help adopting stabilised earth construction

to address urban low-cost housing crisis:an understanding by construction professionals

Mohammad Sharif Zami

Received: 24 June 2010 / Accepted: 21 March 2011 / Published online: 9 April 2011 Springer Science+Business Media B.V. 2011

Abstract Addressing urban housing crisis is an enormous challenge for most of the

countries due to the increasing cost of the building material. Therefore, affordable alter-

native building material can make a breakthrough to the urban housing crisis. In the light of

current success of stabilised earth construction in urban low-cost housing, it is important to

find out the potential drivers that can help to adopt this building material. This paper aims

to identify and highlight these drivers from the method of literature review and validates

through a Delphi technique.

Keywords Construction Drivers Earth Housing Professionals Stabilised Urban

1 Introduction

Compressed stabilised earth blocks are becoming popular in various parts of the world with

the introduction of sustainable construction concepts (Jayashinghe 2007). Although most

of the developed countries do have well-structured and effective programmes to address

the environmental sustainability through the use of energy efficient appropriate construc-

tion materials, stabilised earth is not widely used. More surprisingly, most of the con-

struction professionals from developed and developing countries do not even know about

the contemporary stabilised earth construction (Zami and Lee 2010a, 2010b). The

unawareness about this building material amongst the construction professionals makes us

aware that, there are inhibitors which make contemporary stabilised earth construction

unpopular. But, it is evident from the literature review that experimental stabilised earth

construction projects are a success in many developing (India, Sudan, South America,

Southern and Northern Africa) and developed (Australia, Germany, Austria and France)

Readers should send their comments on this paper to [email protected] within 3 months

of publication of this issue.

M. S. Zami (&)

Department of Architecture, College of Environmental Design, King Fahd University of Petroleum

and Minerals (KFUPM), P. O. Box: 1802, Dhahran 31261, Saudi Arabia

e-mail: [email protected]

123

Environ Dev Sustain (2011) 13:9931006

DOI 10.1007/s10668-011-9301-0


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countries to address urban housing crisis (Adam and Agib 2001; Mubaiwa 2002; Zami and

Lee 2008). Together with other forms of unbaked earthen construction, such as mud-brick,

rammed earth has a long and continued history throughout many regions of the world.

Major centres of rammed earth construction include North Africa, Australasia, and regions

of North and South America, China and Europe, including France, Germany and Spain(Maniatidis and Walker 2003). In Devon (England), there are 40,000 cob buildings still in

everyday use (Abey and Smallcombe 2007). Therefore, drivers need to be devised to make

stabilised earth construction adoptable to the professionals and users. This paper aims to

identify and highlight these potential drivers in the light of its use on site and performance

of environmental sustainability. It is pertinent to analyse the drivers that potentially can

help the adoption of this technology. A critical literature review method was adopted in

this paper to investigate and identify the drivers and validated with the help of Delphi

technique. The following section reviews the literature on drivers influencing the adoption

of earth construction to address urban low-cost housing crisis. First, a critical literature

review method is adopted in this paper to investigate and identify the potential drivers

influencing the adoption of this building material to address urban low-cost housing crisis

and second, the identified inhibitors is validated through a Delphi technique.

2 Contemporary technological innovation of stabilised earth construction

Most of the drawbacks associated with earth houses can be overcome by suitable

improvements in design and technology, such as soil stabilisation, appropriate architecture,

and improvement in structural techniques (Lal 1995, p. 120). Therefore, the drawbacksfound in several literatures relate to the experience of un-stabilised earth construction.

Problems of earth wall erosion by rain and flood water, rodents making holes in the wall

and floor, and poor performance during earthquakes can be solved by stabilising the earth

(Zami 2010). Vernacular earthen houses located in seismic areas are at risk because of their

inherent structural vulnerability. It is possible to provide reinforcement to earthen buildings

in order to improve their structural performance and to prevent their collapse during

earthquakes (Blondet and Aguilar 2007). Furthermore, it is important to take note that

lack of durability and structural limitations of earth construction is the most frequently

mentioned drawback of earth construction mentioned in the literature.

According to Blondet and Aguilar (2007), most vernacular earthen houses are builtwithout professional intervention and thus with poor construction quality. In addition, most

present-day earthen houses are built without any structural reinforcement, with several

storeys, thin walls, large windows and door openings, irregular plan and elevation con-

figurations, these buildings are extremely vulnerable and suffer significant damage or

collapse during earthquakes (Blondet and Aguilar 2007). During the last three decades,

researchers at the Catholic University of Peru (PUCP) have attempted to find solutions for

improving the seismic performance of earthen buildings. The principal alternative solu-

tions of seismic reinforcement for these vulnerable buildings consist of internal cane mesh

reinforcement, external wire mesh reinforcement and external polymer meshreinforcement.

According to Maini (2007), extensive research was carried out to develop cost-effective

technology of reinforced masonry with hollow interlocking CSEBs. Vertical and horizontal

reinforced concrete members supported the masonry so as to create a box type system

which can resist disasters. As a result of the research, two types of blocks have been

developedthe square hollow interlocking block suitable for a two storied building and

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the rectangular hollow interlocking block suitable for a single story building. This tech-

nology has been used extensively in Gujarat for the rehabilitation after the 2001 earthquake

with a 6-month technical assistance from Auroville Earth Institute and with this assistance

the Catholic Relief Services built 2,698 houses and community centres in 39 villages

(Maini 2007). According to Maini (2005), this technology has been approved by theGovernment of Gujarat (GSDMA) as a suitable construction method for the rehabilitation

of the zones affected by the 2001 earthquake in Kutch district (Fig. 1), the Government of

Iran (Housing Research Centre) as a suitable construction method for the rehabilitation of

the zones affected by the 2003 earthquake of Bam (Fig. 2), the Government of Tamil

Nadu, India (Relief and Rehabilitation) as a suitable construction method for the reha-

bilitation of the zones affected by the 2004 tsunami of Indonesia (Maini 2007).

According to Minke (2006), earth as a building material has lost its credibility chiefly

because most modern houses with earth walls cannot withstand earthquakes and because

earth is viewed a building material for the poor. In this context, it is worth mentioning that

a census conducted by the Salvadoran government after the earthquake of 13 January 2001

(measuring 7.6 on the Richter scale) states that adobe houses were not worse affected than

other types of construction (Minke 2006). Minke (2006) also explained about earthquake-

resistant earth construction to address the low-cost housing crisis in Guatemala. A bamboo-

reinforced panelled rammed earth wall technique was developed in 1978 as part of a

research project by the BRL, and successfully implemented jointly with the Francisco

Marroqun University (UFM) and the Centre for Appropriate Technology (CEMAT), both

in Guatemala.

In 1998, the BRL developed another reinforced rammed earth wall system that was

utilised for a low-cost housing project built in cooperation with the University of Santiagode Chile in Alhue, Chile, in 2001. The examples of these earthquake-resistant earthen

houses show that contemporary earth construction is durable enough to replace conven-

tional brick and block construction to address the low-cost housing crisis even in the

earthquake-prone localities. Therefore, natural disasterresistant contemporary earth con-

struction is effectively solving the problems of natural disaster destructive to shelters all

over the world in particular in India and South America.

Fig. 1 Houses built by the CRSGujarat, India. 2698 houses built in a year time, in 39 villages. Source

Maini (2005)

Drivers that help adopting stabilised earth construction 995

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Structural limitation is one of the major drawbacks of earth construction highlighted in

literature review. Related to this, Maini (2005) shows enough examples of buildings with

large spans constructed of compressed stabilised earth blocks (CSEB) and the research and

development seeks to optimise the structures by increasing the span of the roof, decreasing

its thickness and creating new shapes. Note that all vaults and domes are built with

compressed stabilised earth blocks, which are laid in free spanning mode (withoutformwork), which has been developed by the Auroville Earth Institute and this technique is

a development of the Nubian technique (Maini 2005). Figure 3 shows a vault measuring a

diameter of 7.9 m constructed out of CSEB and Fig. 4 shows a dome measuring 22.16 m

of a temple constructed out of CSEB. Therefore, these examples support that contemporary

stabilised earth construction is able to overcome the drawback of structural limitation.

Fig. 2 Houses built by the International Blue Crescent. BamIran. Source Maini (2005)

Fig. 3 Dome of the Dhyanalingam temple, Coimbatore, 22. 16 m dia, 7.90 m rise, 570 tons. Built in

9 weeks. Source Maini (2005, p. 11)

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3 State of art review on drivers that help adoption of earth construction

The drivers that help to encourage the adoption of contemporary earth construction are

identified through a critical review of the literature and summarised in Table 1.

All the drivers identified in Table 1 lack empirical evidence and it would seem from a

thorough review of the literature that sparse research to date has been undertaken to

substantiate whether the drivers in Table 1 are real or mere speculation. It is questionable

whether they are the authors perception and thus lack empirical data to substantiate the

findings. Therefore, this paper aims to develop a holistic understanding of the drivers that

can help the widespread adoption of contemporary stabilised earth construction by pro-

fessionals to address the urban low-cost housing crisis. It is important to note that Driver 2

in Table 1 is already explored in many countries of the world. Australia, New Zealand,

USA (New Mexico), Zimbabwe, Germany and Spain has published the national standards

and reference documents for earthen construction (Maniatidis and Walker 2003). Mani-

atidis and Walker (2003) also noted that at various times a number of other countries that

have produced codes or national reference documents for earthen construction. Accordingto Houben and Guillaud (1994), these include France, India, Tanzania, Mozambique,

Morocco, Tunisia, Kenya, Ivory Coast, Mexico, Brazil, Peru, Turkey and Costa Rica.

Many of these documents do not cover rammed earth. In recent times, CRATerre has led to

the development of regional standards for pressed earth block construction (Maniatidis and

Walker 2003).

4 Research methodology

After a critical review of the existing literatures, it appears that there is a lack of structured

research, to date, carried out to identify and understand the potential drivers of contem-

porary stabilised earth construction in urban low-cost housing. In addition, the drivers

identified by different practitioners and researchers mentioned in the literature are gen-

erally written from their perception, and thus, there is a lack of empirical data and vali-

dation through the execution of a research methodological process. The critical review of

Fig. 4 Vault of Mirramukhi School at Auroville, CSEB. 10.35 m span, 2.25 m rise, 30 tons, built in

3 weeks. Source Maini (2005, p. 11)


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Table 1 The adoption drivers of contemporary earth construction

Drivers (summarised from the

literature review)

Authors

1. Promotion of earth architectureand construction by the

government, professional, all

stakeholders through all public

media.

Jagadish (2007, p. 2627), Morton(2007, p. 377), Blondet and

Aguilar (2007, p. 9), Houben

et al. (2007), Easton (1996,

p. 19), Elizabeth (2005), Adams

(2005), Baiche et al. (2008, p. 7)

Sparse structured research wascarried out to identify these

drives. Therefore, it is authors

perception

(a) Systematic campaigns among

construction professionals.

(b) Industry recognised

marketability of earth

construction.

(c) Educational campaigns to reach

awareness of the seismic risk,cultural transformations to adopt

better construction techniques

with earth.

(d) Campaigns in favour of

sustainable built environment

and against global warming.

2. Setting a building code for earth

architecture and construction.

Morton (2007, p. 377), Norton

(1997, p. 8), Eisenberg (2005),

Minke (2006, p. 196), Baiche

et al. (2008, p. 7).(a) Setting an industry recognised

standard and quality control

criteria.(b) In order to disseminate

successfully tested earth

construction techniques,

guidelines should be developed.

3. Organising a training

programme for professionals,

builders, users, and all building

stakeholders.

Jagadish (2007, p. 26), Houben

et al. (2007, p. 39), Minke (2006,

p. 196).

(a) Training programmes amongst

construction supervisors.

(b) In order to disseminatesuccessfully tested earth

construction techniques, training

courses should be offered.

4. Introducing earth architecture

and technology in university

degree programmes and courses.

Jagadish (2007, p. 26), Houben

et al. (2007, p. 39), Castells and

Laperal (2007, p. 100), Norton

(1997, p. 8), King (1996, p. 5)(a) An innovative approach in

educational pedagogy for earthen

architecture from all the relevant

educational institutions.

5. Technological development andinnovation of earth construction.

Jagadish (2007, p. 26), Baicheet al. (2008, p. 7)

(a) Setting quality control criteria

of CSEB manufacturing

machines.

Source Author: 2009

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the literature permits the author to recognise and identify the existing up-to-date drivers

mentioned by different researcher, in which it appeared that there is sparse structures

research. The drivers found in the literature are written in the light of researchers expe-

rience and perception. Therefore, a well-structured research technique should be devised to

validate the drivers identified from the literature review. A Delphi technique is chosen inthis paper as an appropriate method to validate the drivers which effectively collect data

from construction professionals and compare the list of drivers found in the existing

literature.

The Delphi research technique is chosen as the mode of data collection due to its ability

to explore the drivers that help the widespread adoption of stabilised earth construction in

urban low-cost housing. The Delphi technique can be used when there is incomplete

knowledge of a problem or phenomena (Adler and Ziglio 1996; Delbeq et al. 1975). This

technique can be applied to problems that do not lend themselves to precise analytical

techniques but rather could benefit from the subjective judgments of individuals on a

collective basis (Adler and Ziglio 1996) and to focus their collective human intelligence on

the problem at hand (Linstone and Turloff 1975). Also, the Delphi technique is used to

investigate what does not yet exist (Czinkota and Ronkainen 1997; Halal, Kull, and

Leffmann, 1997; Skulmoski and Hartman 2002). Therefore, for this research, the Delphi

technique is chosen as a suitable research technique because the results will offer an

informed look at the current and potential status of the drivers of stabilised earth con-

struction to address the urban low-cost housing crisis in general. Based on the nature,

attitudes and beliefs of a carefully selected group of expert respondents, the drivers will be

captured. A substantial literature review in Sect. 2 found that the identified drivers suffer

from lack of empirical data. Due to these lacking in the prescriptions made by differentprofessionals and researchers in this area, the results of this Delphi technique will be

relevant, provide clarification the drivers identified in the literature review.

As there are a limited number of contemporary earth construction experts in the world,

the most notable of these were contacted as expert panellists for this Delphi technique. A

list of 34 participants (experts) was contacted from both the private and public sector that

would appear to have the required knowledge and/or experience of the subject. Therefore,

34 letters were sent out inviting them to take part in this Delphi technique. A total of 14

individuals responded and agreed to participate, equating to a 41% response rate. Out of

the 14 individuals, 7 were academician researchers, 1 was a practitioner, and 6 were

practitioner researchers. During the second round of administering the Delphi technique, 3academician researchers and 1 practitioner experts did not respond, which made a total of

10 participants. Delphi procedures tend to depend on the questions being asked, sample

size and degree of consensus being reached (Rowe and Wright 1999). The panel size of 10

fits within the guidelines recommended for Delphi studies. Helmer and Dalkey used a

panel of seven experts in their original Delphi experiment in 1953 (Helmer 1983). Linstone

and Turoff (1975) suggest a panel size of anywhere from 10 to 50 participants. According

to Andranovich (1995), if the group of experts is fairly homogeneous (sharing similar

opinions) then 10 to 15 panellists will be enough and if there are diverse interests present

among the experts, then the size of the group will need to be increased to ensure balance.For most community-oriented Delphi, 30 is about as large a group. Brief profiles of the 14

experts whom participated in this Delphi interview technique is shown in Table 2.

The number of rounds in the Delphi technique is variable and dependent upon the

purpose of the research. Delbeq et al. (1975) suggest that a two or three iteration Delphi is

sufficient for most research. If group consensus is desirable and the sample is heteroge-

neous, then three or more rounds may be required and if the goal is to understand nuances


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Table 2 Profile of the experts who participated in the Delphi technique

No. Name Profession/designation and

country

Experience

(years)

Remarks

01 ExpertA Civil Engineer, Professor(Brazil) 30 Author of many published articles oncontemporary earth construction.

02 Expert

B

Architect/Landscape Architect,

Professor in architecture.

(United Kingdom)

40 Designer of earth building for University of

Malawi and has published a book on

landscape architecture.

03 Expert

C

Engineer

(Australia)

30 Practitioner and researcher on contemporary

stabilised earth construction.

04 Expert

D

Architect, Assistant Professor.

(India)

05 Specialised in civil engineering and earth

construction.

05 Expert

E

Chartered architect and

consultant

in architectural conservationand heritage management,

Professor

in architecture.

(United Kingdom, Ghana)

40? Worked in many African countries and has

published many journal papers on

vernacular architecture.

06 Expert

F

Professor of postgraduate

Studies.

(India)

44 Organizer of International Symposium on

earthen structures, 2007. A pioneer

researcher in contemporary earthen

architecture.

07 Expert

G

Architect, Senior Lecturer

(United Kingdom)

35 Specialised in conservation and a researcher

in un-stabilised earthen architecture.

Supervised many PhD students in earthconstruction.

08 Expert

H

Engineer, Associate Professor,

researcher in contemporary

earth construction.

(India)

30 Organiser of an international Symposium on

earthen structures, 2007. A pioneer

researcher in contemporary earth

construction.

09 Expert

I

Civil Engineer, researcher in

contemporary earth

construction.

(Portugal)

06 Author of many published articles on

contemporary earth construction.

10 Expert

J

Architect, Visiting Professor

(Austria)

05 Earthen architecture practitioner and has

constructed many earth structures.11 Expert

K

Lecturer, Earth Construction

researcher

(United Kingdom)

08 Researcher of stabilised earth construction.

12 Expert

L

Research Fellow, researcher in

contemporary earth

construction.

(United Kingdom)

12 Author of many articles and researcher.

13 Expert

M

Senior Lecturer, researcher in

contemporary earth

construction.

(Sri Lanka)

14 Author of many articles and contemporary

earth construction researcher.

14 Expert

N

Architect, PhD researcher in

earth construction.

(Nigeria)

15 Earth construction practitioner and

researcher.

Source Author, 2008

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(a goal in qualitative research) and if the sample is homogeneous, then fewer than three

rounds may be sufficient to reach consensus, theoretical saturation, or uncover sufficient

information (Skulmoski et al. 2007). For this research, only two rounds of the study were

needed for the participants to reach a consensus.

5 Analysis and discussion of findings from round one Delphi technique

The Delphi technique adopted in this paper consists of two rounds of question whereby the

second round question was constructed from question and feedback acquired from the

previous round. The aim of the question in the first round was to elicit the drivers that help

the adoption of stabilised earth in the construction of urban low-cost housing. The second

round of the Delphi technique confirms the summarised drivers in rank order acquired from

the first round which were presented to the experts for reconsideration and validation.

5.1 Drivers that help the adoption of stabilised earth construction in urban low-cost

housing

All experts responded to the following question in the first round:

Question What are the drivers that you would suggest and can help adoption of stabilised

earth construction in urban low-cost housing? Please explain and explore your suggestions.

One experts (7%) response was inconclusive. Thirteen experts listed several drivers.

Figure 5 shows the nature and percentages of responses from the experts.Twenty five drivers that can help the adoption of stabilised earth construction in urban

low-cost housing are identified from the experts responses and listed according to their

importance (rank). They are firstly grouped into the categories identified from the literature

review (Sect. 3), and then this was check-listed against the number of times they were

mentioned in this study. Table 3 shows the summarised list of drivers according to their

importance (rank). It is important to note here that there is one additional driver apart from

the five drivers identified in the literature review identified in Delphi Round One and

presented in Table 3.

According to one of the experts, earthen materials are not suitable for all construction

applications in developed countries. On a global scale, it is already the most widely usedconstruction material in the world and so by definition is a popular choice. Earth as a

material offers advantages and disadvantages and so could be used intelligently to suit

certain applications, for example in medium rise office buildings to reduce peak cooling

loads, in stores/archives/museums to regulate humidity without air conditioning. Another

expert was concerned that earthen architecture should be taken more seriously; the tech-

nology should not be considered as low cost or for the urban mass or the urban poor but

as an alternative for both the rich and the poor. This approach will help to overcome the

Fig. 5 According to most experts opinion, there are drivers that help the adoption of stabilised earth

construction in urban low-cost housing


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Table 3 Drivers that will help to adopt stabilised earth construction in urban low cost housing summarised

from the Delphi Round Two

Drivers help to adopt stabilised earth construction (summarised from the

Delphi Round One)

Number of experts

1. Promoting earth architecture and construction by the government,

professional and all stakeholders through all public media.

(a) First and foremost support from competent civil engineering

professional bodies, government organisations working towards

promoting earthen constructionsthis will change the poor peoples

image on earth.

(b) To have a catalogue of successful examples, showing how the

buildings were built, what they look like inside and out, how much they

cost compared with conventional construction and very importantly

how long such buildings have lastedwith pictures after 20 years.

Including comments on the maintenance required.

(c) If really aesthetically pleasing examples can be found, there must belots scattered around the globe with good comments from the occupiers

this could be a positive way of promoting the idea, rather than attempting

to use a utopian vision. For example inhibiting notions need to be

directly addressed such as burglary resistance. Can a thief break in with a

small sledgehammer? As well as termite resistance. Such examples

should be of the quality to make people feel that they would really like to

have a house like that. Maybe show the whole buildings first; and only

after that reveal that it is made of SSBs and that it is x% cheaper than an

identical one of conventional construction, with no drawbacks.

(d) Build a number of successful, high-profile, high-status earth buildings.

Develop skills and techniques and solve all problems through these

builds. Demonstrate significant understanding through research and peerreviewed publishing. Ultimately earth building will become fashionable,

reliable and respected. It should then be relatively simple to apply the

technique to a mass market.

(e) Widespread publicity for well-designed projects.

(f) A sustained programme of public education through the media.

(g) Convince brick manufacturers to consider offering unfired stabilised

bricks as an alternative.

Ten (10)

2. Technological development and innovation of earth construction.

(a) Find some cheap solutions to strengthen earth constructions.

(b) In the research of possible reinforcement techniques of these kinds of

buildings, it is important to consider the use of compatible materials.

These materials should be able to be produced in an industrial way.(c) Earth constructions need to be popular to show that buildings can be

resistant and can protect life properly in earthquakes.

(d) Show the consumers that earthen buildings can have the same level of

comfort as normal buildings and have a higher degree of sustainability

than the other options.

(e) More dissemination of scientific and technical knowledge is vital

(f) Professionals should devote more time to learn about the technology in

their localities and develop the desire to improve these traditions to meet

contemporary needs.

(g) Professionals should identify the advantages of this technology within

their locality and as well as the drawbacks. These drawbacks should be

accepted as limitations.

Eight (08)

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Table 4 Drivers that help in the adoption of stabilised earth construction in urban low-cost housing

summarised and adopted from the Delphi technique

Drivers that will help to adopt stabilised earth construction (summarised and adopted from the Delphi Round

Two)

1. Promoting the earth architecture and construction by the government, professionals, and all stakeholders

through all public media.

2. Technological development and the innovation of earth construction.

3. Organising training programmes for professionals, builders, users and all building stakeholders.

4. Introducing earth architecture and technology in university degree programmes and courses.

5. Setting a building code for earth architecture and construction.

6. Organising conferences, publishing books and scientific articles on earth architecture.

Table 3 continued

Drivers help to adopt stabilised earth construction (summarised from the

Delphi Round One)

Number of experts

3. Organising training programmes for professionals, builders, users andall building stakeholders.

(a) Setting up of demonstration units in research labs, academic offices, so

that the general masses are aware and become familiar with the end

product.

(b) Thorough, earth-material based technical guidelines on the adoption

and construction techniques using earth.

(c) Every earthen building project requires training of artisans; this is

because since the technique is not consistently in use, it is difficult to

retain these artisans at the completion of one project. Thus, every new

project entails regrouping of a few old hands and training new ones.

Therefore, for the technology to be sustainable it requires consistency.

One single government project or demonstration building is not enoughto attain this consistency.

(d) Regular workshops awareness and training programmes for architects

and civil engineers in the manufacture and use of earth (stabilised or un-

stabilised) blocks.

Six (06)

4. Introducing earth architecture and technology in university degree

programmes and courses.

(a) Integration of earth construction in various curricula.

(b) Investment in engineering and architecture courses. Young people have

much more of an open mind. So, create courses about earth construction

and introduce them in the university.

(c) More awareness is necessary, for example, gradually including this

technology in engineering curricula under sustainable construction.

Five (05)

5. Setting of building code for earth architecture and construction.

(a) Codes of practice should be published soon.

(b) Adopt technical standards for earth construction.

Four (04)

6. Organising conferences, publishing books and scientific articles on earth

architecture.

(a) Organise conferences about the use of earth construction in order to

spread it.

(b) In addition to the scientific publications, simpler books and articles are

necessary to popularise the technology.

Four (04)


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prejudices of earth construction amongst all kind of people in society. Therefore, this

Experts concern is also supported by the previous expert as they state; this technology

should be introduced more to the upper strata of the society with architecturally pleasing

houses.

According to one of the expert, concentration on its use in rural areas where the costbenefits of using earth construction technology are greater than in urban areas and the

material is more aesthetically appropriate in a rural environment, in a soft, green landscape

setting, rather than the hard landscape of the city. It is worth mentioning here that the

drivers identified from round one did not differ from the drivers adopted in the literature

review (Sect. 3) except an additional driver (number 6 in Table 3) was identified in this

Delphi technique.

6 Analysis and discussion of the findings of the Delphi second round

Four experts did not participate in Round Two of the Delphi technique. Therefore, only 10

experts participated in this second round, and the same question was asked in this round.

The following sub-section summarises and analyses the responses of the question of this

second round.

6.1 Drivers that help the adoption of stabilised earth construction in urban low-cost

housing

There were 25 drivers summarised and identified from the Delphi First Round interviews.These drivers influencing the adoption of stabilised earth construction in urban low-cost

housing were organised in the list according to their importance (rank) and sent to the

experts in the second round interviews for validation. No experts commented on this in the

second round. Therefore, these drivers were agreed on unanimously. After careful con-

sideration of the experts second round interviews, the drivers adopted are shown in

Table 4 and Fig. 6 shows their importance (rank).

Fig. 6 Importance (rank) of the drivers that potentially helps the adoption of stabilised earth construction in

urban low-cost housing

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7 Conclusions

This paper has investigated and analysed the state-of-art review of literature of the drivers

that help adopting contemporary earth construction in general and validated through

Delphi technique. It was found that there is a lack of structured research, to date carried outto identify the drivers. Therefore, it was imperative to substantiate and validate the findings

of the literature review with the help of a structured research method. Delphi technique was

used as an appropriate research method to substantiate and validate the drivers. Diversified

drivers were stated by the experts in both rounds of the Delphi technique from which six

drivers were summarised and identified. It is important to note that one additional driver

was identified in the Delphi technique in addition to five drivers identified in the literature

review. Furthermore, according to experts in this study, promotion of contemporary sta-

bilised earth construction through the public media got the highest priority to adopt this

alternative building material to address urban low-cost housing crisis.

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