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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)
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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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