THE NEED FOR VERNACULAR MUD HUTS OF RANCHI
TO RE-ADAPT IN RESPONSE TO THE CHANGING
CLIMATE OF RANCHI OVER THE LAST 30 YEARS.
Adaptation and innovation in
Techniques of Construction for the
Future of Vernacular Architecture.

BI R L A I N S T I T U T E O F T E CH N O L O G Y , M E S R A,
R AN CH I , J H AR K H AN D .
I N D I A.
Janmejoy Gupta,
Dr.M.Chakraborty,R.Agrawal.

Vernacular architecture.
 Vernacular architecture is architecture based on
localized needs and construction materials,
reflecting local traditions and influenced by local
culture and climate.
 Quite a few studies have shown that vernacular
homes use various passive strategies to
create comfortable conditions inside them.
Meir and Roaf ,(2006).

Vernacular architecture
 In developing countries, where most of the
population remains in rural areas using
traditional buildings and technologies, the
only feasible way to provide them with better living
conditions is to upgrade traditional and
vernacular homes. (Meir & Roaf, 2006).

Jharkhand-some facts and figures..
 Along with a thermally-responsive
construction, the architecture of Jharkhand
responded to interactive social life by creating
community courtyards.
 Jharkhand has, as per the 2011 census, 75.9 % of
its total population living in rural areas, and it
is in this context that the development of proper
rural architecture is important.
 As per 2011 Census, 58.5 % of households in
Jharkhand have mud walls and 53.4 % of total
households have Clay-tiled roofs.

Vernacular architecture of Jharkhand.
 As per Gautam (2008) before British colonization in
1870, Jharkhand had an agrarian society. Huts made
of mud walls and thatched roofs were the
standard construction.
 Over time, as an effect of industrial hybridization,
the thatch in the huts was replaced by sun-dried or
burnt clay Mangalore tiles that are today more
commonly used as roofing material for the huts as
has been done in the hut studied.

Vernacular architecture of Jharkhand.
 The walls were made of a
special type of mud obtained
by souring earth by
adding vegetable waste
and leaving it to mature.
 The decaying waste produced
tannic acid and other organic
colloids, greatly improving
the mud’s plasticity
(Cooper & Dawson,
1998).(Figure 1) This mud
was then mixed with cow
dung, chopped straw, and
gravel or stones to make
the raw material for the
walls.
Figure 1: Special mud blocks
left with vegetable waste
matter to mature for wall
construction. Source: Gautam
(2008).

Figure 3: Typical types of mud huts in studied
area (source: Sketched by author).
Figure 2: Mud wall with wooden-post of typical hut
–plan & detail (Reproduced from Dhar, 1992).

Mud-Climate Responsiveness
…previous studies.
 P.R. Reddy and B.Lefebvre (1993) showed that
traditional mud houses create thermal comfort.
 John J. Morony (2005) states that there is strong
evidence to suggest that as a construction material adobe
keeps a building significantly warmer in winter and
cooler in summer than other non-earth based
materials.
 Tim White (2009) states that earthen materials have
traditionally been used to create comfortable homes.
 Incorporating earth in buildings minimizes the rise
and fall of humidity and temperature in building
envelopes.

Objectives…
 Most of the vernacular mud architecture existing at present was
built keeping in mind climate conditions prevalent in the past.
 The required modifications in the existing design features identified
in response to the changes in the prevailing climate.
 Mud huts offers reasonably comfortable indoor conditions
in summer and winter than other non-earth based
materials due to the interplay of three fundamental
thermal properties of mud.
 These are: Thermal Mass or Thermal Capacity, Thermal
Transmittance (U-value) and Thermal Insulation. These
three thermal properties can be modulated in existing mud huts of
Ranchi by incorporating minor changes in construction techniques.

Prevailing climate of Ranchi over the
years.
Thermal Properties of existing huts with
earth.
Effect of changes in construction techniques on
thermal properties of rammed earth. (as per
existing studies on subject).
Ideal Thermal Property of
mud desired as a
consequence of the changes
in construction technology.
Hot in summer daytime, but cooler in
summer evening and night time.
Diurnal temperature Range in peak
summer is 15 degree Celsius.
High Thermal Mass/Capacity. Lower wall thickness allows slightly lower thermal
capacity (Refer Table 1) - which helps in reducing
temperatures inside mud hut in peak summer
nighttime, keeping in mind higher temperatures
recorded inside mud hut with respect to lowered
outside temperatures during peak summer night-
time
Moderate Thermal
Mass/Capacity.
Cold in winter Insulation Properties: Rammed earth has
poor insulating properties.
More amount of insulation will cause upto 5 degree
higher temperatures recorded inside mud huts in
winter.
Better Insulating Properties.
Hot in summer, cold in winter. Moderately high Thermal
Transmittance (U-values)
It is expressed in watts per square metre
per kelvin, or W/m²K.
Symbolically, U=k/l, where k is the
conductivity of the material, l is thickness
of material.
The lesser the U value of the building
material, more is the resistance offered by
the building material to the flow of heat
from outside to inside or from inside the
buildingto outside.
Madhumati et al (2014) states that rammed earth
wall of 300 mm thickness when built with 4 inch of
rigid insulation inserted in the centre of the wall,
(Refer Figure below) results in the U value to be
brought down to as low as 0.65 watt/square meter
Kelvin.
rammed earth wall built with rigid insulation
inserted in the centre.
Lower Thermal Transmittance
(U-values)
Table 1: Summary of the thermal properties of mud with respect to prevailing climate of Ranchi and existing literature study.

Thermal properties of wall materials of mud buildings. (Source: Soebarto, 2009)
Thermal Mass or Thermal Capacity.

As per Veronica Soebarto , (2009), who carried out an analysis of indoor
performance of houses using rammed earth walls, while rammed earth
walls indeed have high thermal mass, the thermal resistance of
rammed earth alone is not great enough to retain heat in cold climate.
Her studies further show that in summer, the un-insulated rammed
earth houses have similar performance to the insulated rammed earth
house; however, without using any heater, the un-insulated houses
could be colder by as much as 5 degrees in winter.
Sanjay Kumar et al (1994) talks about the different roof and wall
designs/treatments that have been proposed, in which the finding was
that a thin layer of cow dung slurry inside the wall cavity reduces the
incoming heat flux through the mud walls.
Thermal Insulation.

As per Brager and De Dear (2001), proposed revisions to ASHRAE 55-2004, ‘Thermal
Environmental Conditions for Human Occupancy’, include a new adaptive comfort standard
(ACS) that allows warmer indoor temperatures for naturally ventilated buildings during summer.
Optimum comfort temperature, Tc (comfort temperature) was calculated as per formulae given
below-
Tc = 0.31 To (DBT) + 17.8,............... (in degree celsius)
Though metrics have been developed to quantitatively define thermal comfort, it is inherently
subjective.
As per Nicol (2001), Humphrey in 1981derived a mathematical relationship between the
optimum comfort temperature (Tc) and mean outdoor temperature (To) for a passive building:
Tc = 12.1 + 0.53 To. He collected data from comfort surveys from all across the world and plotted
the temperature reported as comfortable against outdoor temperatures for the month of
survey.
Nicol (2001), concluded after similar research in the Indian sub-continent that, Tc = 17.0 + 0.38
To. The difference between the two formulas is the subjective nature of thermal comfort.

The minimum comfort temperature values as per Nicol (18.9 degree
Celsius) is more than the average 15 degree Celsius recorded over the
seven days inside the mud hut in winter. (Figure 11)
The average recorded temperature inside the mud hut over seven days
in summer, (35 degree Celsius) (Figure 10) is more than the allowed
upper comfort maximum temperature limit of 32 degrees as per Nicol.
Optimum comfort temperature, Tc (comfort temperature), calculated as
per Brager and De Dear’s adaptive comfort standard (ACS) come to
about 18.4 degree Celsius to 30.94 degree Celsius based on outside Dry
Bulb Temperatures measured through the year.
Here too, as per Adaptive Comfort Standard, the recorded
temperatures inside the mud hut in peak of summer is above the
threshold comfort value and the recorded temperature inside the mud
hut in peak winter is below the threshold comfort temperature.

Zone temperature vis a vis Outside Temperature for Square dwelling , Hourly temperatures – 20th January.
Zone temperature vis a vis Outside Temperature for Square dwelling , Hourly temperatures – 16 th February.

Zone temperature vis a vis Outside Temperature for Square dwelling , Hourly temperatures – 21st March.
Zone temperature vis a vis Outside Temperature for Square dwelling , Hourly temperatures – 20th April.

Zone temperature vis a vis Outside Temperature for Square dwelling , Hourly temperatures – 20th July.
Zone temperature vis a vis Outside Temperature for Square dwelling , Hourly temperatures – 22nd August.

Zone temperature vis a vis Outside Temperature for Square dwelling , Hourly temperatures – 20th September.
Zone temperature vis a vis Outside Temperature for Square dwelling , Hourly temperatures – 21st October.

Zone temperature vis a vis Outside Temperature for Square dwelling , Hourly temperatures – 16th November.

JAN FEB MRC APR MAY JUNE JULY AUG SEPT OCT NOV DEC
Series 1 84.4 84.7 65.3 57.9 67.7 66.7 90.9 94.9 89.9 87.4 86.5 89.2
0
10
20
30
40
50
60
70
80
90
100
MAXIMUM HUMIDITY

JAN FEB MRC APR MAY JUNE JULY AUG SEPT OCT NOV DEC
Series 1 34.8 36.4 20.1 24.3 28.4 41 82.3 72.2 73.4 45.8 45.2 35.4
0
10
20
30
40
50
60
70
80
90
MINIMUM HUMIDITY

Figure : Zone temperature vis a vis Outside Temperature for Square dwelling Hourly temperatures - 27th
July.
(Blue line- temperatures inside the hut, Red line-Outside temperature.)
Wind bringing down temperatures…

Change in Climate (over the past 30
years)
Changes in Design features in
standard mud huts with clay-tiled
roofs required.
Practical Application in Mud huts. Schematic Sketches.
Average maximum temperatures in
2012-2013 have increased
considerably, from what was recorded
in 1986-87 and in the intervening
decades.
Increased maximum temperatures in
summer call for better wall & roof
insulation.
Proper roof insulation by the following
methods:
1. Wooden beams and boards covered
with straw and protective mud layer.
2. Timber substructure carrying clay tiles
covered with mud.
3. Straw thatch on pole timber on bamboo
substructure.
Average minimum temperatures in
2012-2013 have decreased for all the
months from the values recorded in
1986-1987 and in the intervening
decades.
Decreased minimum temperatures in
winter necessitate the need for more
amount of wall insulation.
Proper insulation should be used. This
insulation can be in the form of a thin
layer of cow dung slurry inside the wall
cavity as suggested by Sanjay Kumar et
al (1994).
Compacted earth rendered with cow dung
slurry.
Source of above figures: Bansal,N.K. and Minke,G.(1988). Climatic zones and rural housing in India. Zentralbibliothek Publishers. pp. 62-68, pp.132-149.
Increase in summer-time temperatures
in general.
High thermal capacity of walls cause
temperatures inside the hut to remain
high even at nighttime when outside
temperatures have decreased.
Reducing thermal capacity of walls from
450 mm thick walls to 250 mm-300 mm
walls.
Relative Humidity levels have increased in the months of July, August and September.
Table 3: Changes in Design features required in standard mud huts in tune with changes in climate.

Separate summer time and winter time rooms.

Cob Wall Section. (source: drawn by author)
Wattle and Daub Wall Section.
(source: drawn by author)
Lower Thermal-Capacity walls

More Amount of Nocturnal Ventilative Cooling.

Limitations of the study.
These innovations like reducing thermal mass of walls and insulation suggested
above could not be tested whether they actually work in Ranchi’s climate, (other
than the U-shaped dwelling with courtyard which was selected as a model
dwelling on the basis of showing better thermal performance through the year as
compared to the seven other sub-types).
However, examples of previous studies which have been covered in the
Literature Review, show that in other areas with similar climatic characteristics
as that of Ranchi, these techniques have worked.

Dissemination of recommendations to the users.
Use of rationalized traditional technologies, like that done and displayed at the
Rural Building Centre of National Institute of Rural Development, Hyderabad
(NIRD), a HUDCO initiative, which has created model huts for 16 diverse
climatic areas of India including Kutch regions, hot-dry area, coastal high-rain
areas and Deccan Plateau. However the region Jharkhand with its composite
climate does not feature in the list of those 16 regions.
It would be a great boon to the vast rural populace of Jharkhand if they could see
their modest mud-house being improved by use of rationalized traditional
technologies in tune with the changes in climate and if they could be given a
easily constructible prototype mud-hut on the lines of the 16 other prototypes
being developed by the NIRD initiative. These can be systematically being made
available to the rural poor through awareness programs, government
initiatives and loans/grants for self-building their huts.

References.
Meir, I.A. and Roaf, S.C. (2006). The future of the vernacular: Towards new methodologies for the
understanding and optimization of the performance of vernacular buildings. In: Asquith,L. and
Vellinga,M. (Eds). Vernacular architecture in the twenty-first century: Theory, education and practice.
Oxon: Taylor & Francis.
Nicol (2001) Nicol, J. F. (2001). Climate and thermal comfort in India. In: Krishan, A., Baker, N.,
Yannas, S. and Szokolay, S.V. (Eds.). Climate responsive architecture: A design handbook for energy
efficient buildings. Tata McGraw-Hill Publishing Company Limited, New Delhi. pp. 59-67.
Reddy, P.R. and Lefebvre, B. (1993). Rural housing and perception of inhabitants: Case study of an
Indian village. International Journal for Housing Science and its Applications. Vol.17(1), pp. 49-55.
Gautam, A. (2008). Climate Responsive Vernacular Architecture: Jharkhand, India. Masters Of Science
Thesis. Department of Architecture, Kansas State University, Manhattan, Kansas.pp-1-40, 54-59 and
81-85.
John J. Morony (2005) Morony,J. (2005).Adobe and Latent Heat: A Critical Connection. Second
Annual Conference, Adobe Association of the Southwest. Northern New Mexico Community College,
El Rito, New Mexico. pp.1-8.
White, Tim. (2009). The effect earthen plasters and exterior lime stuccos have on controlling
humidity and temperature in building envelopes. Sixth Annual Conference. Adobe Association of the
Southwest, Northern New Mexico Community College, El Rito, New Mexico. pp.15-20.
Dhar, S. (1992). Regulating privacy: A comparison of the garo and santal cultures using the human
relations area files. Unpublished Masters of Architecture, Kansas State University, Manhattan.
Soebarto, V. (2009). Analysis of indoor performance of houses using rammed earth walls. In: Eleventh
International IBPSA Conference, Glasgow, Scotland.
Madhumathi,A., Vishnupriya,J. And Vignesh,S. (2014). Sustainability of traditional rural mud houses
in Tamilnadu, India: An analysis related to thermal comfort. Journal of Multidisciplinary Engineering
Science and Technology (JMEST).Vol.1, Issue 5, pp. 302-311.

Stone,C., Bagona,M. and Katunsky,D.(2013). Embodied Energy of Stabilized Rammed Earth. Technical Transactions.
Civil Engineering. Issue 3, pp. 395-400.
Minke, G. (2006). Building with earth, design and technology of a sustainable architecture. Basel- Berlin-Boston:
Birkhäuser –Publishers for Architecture, pp. 1-18, 32, 47, 56-61, 107-134, 141-145.
Binici, H., Aksogan, O. and Shah, T. (2005). Investigation of fibre reinforced mud brick as a building material. Elseviers
Science Direct. Construction and Building Materials. Volume 19, pp.313-318.
Binici,H., Aksogan,O.,Bodur,M.N., Akca,E. and Kapur, S.(2007). Thermal isolation and mechanical properties of fibre
reinforced mud bricks as wall materials. Elseviers Science Direct. Construction and Building Materials.Volume 21, pp.
901-906.
Kumar,S., Tiwari,G.N. and Bhagat,N.C. (1994).Amalgamationof traditional and modern cooling techniques in
a passive solar house: A design analysis. Elsevier’s Science Direct. Energy Conversion and Management. Volume 35,
Issue 8, pp. 671-682.
Fix, S. and Richman, R. (2009). Viability of Rammed Earth Building Construction in Cold Climates.
Brager,G.S. and De Dear,R. (2001). Climate, Comfort & Natural Ventilation: A new adaptive comfort standard for
ASHRAE Standard 55. In: Proceedings-Moving Thermal Comfort Standards into the 21st Century, Oxford Brookes
University, UK.
Nicol, F., (2004). Adaptive thermal comfort standards in the hot humid tropics. Energy and Buildings. Vol.No. 36, no.
7, pp. 628-637.
Bansal,N.K. and Minke,G.(1988). Climatic zones and rural housing in India. Zentralbibliothek Publishers. pp. 62-68,
pp.132-149.
http://www.yourhome.gov.au/technical.

THANKS…
That’s all….