1) The document analyzes the thermal performance of traditional mud houses in rural Jharkhand, India through a case study. 2) It describes the typical construction techniques of mud houses in the region, including materials used and wall/roof assemblies. 3) Thermal analysis through simulation found that orientation, surface area to volume ratio, ventilation, building materials, and shading impact heat gain. Improving these elements could enhance thermal performance of mud houses.

1. Thermal Performance of Rural Architecture in
Jharkhand: case-study of typical mud house
AR.JANMEJOY GUPTA & DR.
MANJARI CHAKRABORTY, BIT,
MESRA, RANCHI

2. INTRODUCTION
• Jharkhand as per 2011 census, has 75.9 % of its total population
living in rural areas.
• 30% of the world’s total population live in earthen structures.
• Earthen huts constituted 48% of total residential construction until
1960 in Jharkhand.(Das & Pushplata, 2005).
• An average hut measured approximately 5 to 6 meters (15 to 18 feet)
long and 3 to 4 meters (10 to 12 feet) wide (Dhar, 1992). The huts
vary in size. There are also a considerable number of larger huts that
extend up to 12 to 14 meters in length and 8 to 9 meters in width.
• Huts were arranged in a linear pattern along the main street of a
village, usually amidst a group of bamboo trees. The houses were
normally surrounded by a fence made of bamboo, shrubs, or twigs
that defined the boundary between the public street and the semi-
public courtyard area in front and at the rear of the hut.

3. PHOTOGRAPHS OF RURAL
HUTS
Source: photos by the Author

4. CONSTRUCTION TECHNIQUES
• The huts were made of local materials. Timber, bamboo,
clay, straw, cow dung, and a special variety of grass were
used to build houses (Dhar, 1992).
• The walls was 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).
• This mud was then mixed with cow dung, chopped straw,
and gravel or stones to make the raw material for the walls.
• In the Middle East fibrous ingredients like straw are used to
improve tensile strength of mud bricks.
• Binici et al (2007) investigated the thermal isolation and
mechanical properties of fibre reinforced mud bricks as wall
materials.

5. …continued
• The walls were formed by applying a thick coat of the mixture
on both sides of bamboo/sal log mesh that wrapped around
the posts. The walls are approximately 450 mm (18 inches)
thick.
• The roof rested on nine wooden posts erected in three rows,
with three posts per row (Dhar, 1992).
• These posts were sunk into the raised platform and tied with
wooden beams and purlins that supported the roof structure.
The huts usually had a gabled thatch roof. Bamboo sticks
formed the mullions to support the thatch.
• thatch in the huts was replaced later by sun-dried or burnt clay
Mangalore tiles.

6. The four types of mud-house construction employed are:
• 1. Cob: Fresh lumps of mud [soil & water & local fibre
materials] stacked on each other. Stacking lumps of mud.
• 2. Wattle and Daub: Woven work of sticks intertwined with
twigs or bamboo covered with mud .
• 3. Rammed Earth: Damp earth laid between formwork and
moulded and compacted by ramming.
• 4. Straw-bale: Plastering the bundle of hay with mud.
• Out of these, the Cob method & Wattle and Daub method
is the most commonly used in Jharkhand huts. Wattle and
Daub was the method used in the hut studied.

7. Mud house construction-techniques & types..continued:
Source:Uthaipattrakul, Dh. (2004). Mud-house construction technique.
Building the house with mud. Suan-ngarn-mena Press, Bangkok, 27-50.
Special mud blocks left with vegetable waste matter to mature
for wall construction.
Mud wall with wooden-posts
of typical hut
Source: Gautam Avinash(2008), Climate Responsive
Vernacular Architecture: Jharkhand, India, Masters Of
Science Thesis, Department of Architecture, Kansas State
University, Manhattan,Kansas. Source: Dhar (1992)

8. CLIMATE OF RANCHI
• As per Koppen’s classification, Ranchi has
sub-tropical humid climate.
• A humid subtropical climate as per
Köppen climate classification is a climate
zone characterized by hot, sometimes
little humid, summers and generally mild
to cool winters.
• Summer is followed by the cooler
monsoons, where the region experiences
heavy rains on almost every alternate day
basis. Average high temperatures
decreases during the monsoon season but
the humidity increases.
• Summers tend to be hot, starting from
mid-April and peaking in May and early
June with high temperatures often
touching 40°C. They also tend to be dry,
complete with dust storms, traits usually
associated with arid or semiarid climates.

9. METHODOLOGY-STUDY HUT
• The hut is located in Mesra
village, 16 kms from Ranchi.
Its dimension is 12 meters in
length by 7 meters in
breadth. It is made of mud
walls and has a Mangalore
tiled roof. It has 450 mm
thick mud walls and was
constructed by wattle and
daub construction method.
• The two doors are placed in
the southern side. The
solitary small void like
opening is placed on the
northern wall.

10. 1.PARAMETERS OF STUDY, FIRST PARAMETER
• Orientation: The mud house has its longer side oriented along
East-West Axis. The two doors are placed in the southern side.
The solitary small void like opening is placed on the northern
wall.
Ecotect software analysis of simulated study-hut – Mean radiant temperature (Thermal Comfort) inside mud hut at 12
Noon, 1st June. East-West Orientation of house, void (window like smaller opening) on northern wall.

11. ANALYSIS - Orientation
• The best orientation for least heat gain for rectangular built form
with one side longer than the other is the longer sides facing the
East-South and North-West direction making an angle of about 40
degrees or 45 degrees with the East-West Axis, rather than the
longer side of the building aligned along the East-West Axis as done
in the mud house studied. With the longer side orientated along NW-
SE direction heat gained would be even lesser. Thus, with proper
orientation, the heat gained by the mud house would be even lesser.
Ideal Orientation for heat &
ventilation

12. Ecotect software analysis of simulated study-hut – Mean radiant temperature (Thermal Comfort) inside
mud hut at 12 Noon, 1st June longer side orientated along NW-SE direction, at an angle of 45 degrees to
the East-West Axis. Void on northern wall.

13. 9 AM , 1ST JUNE wrt changed ideal location

14. Window on southern face, results in higher average temperature. Not advisable.

15. 2.Surface Area to Volume Ratio(S/V)
• The total surface area (excluding ventilation opening & including roof area) is
185 square meters in mud hut studied. The total volume is 210 meter cube. The
ratio comes to be 0.88.
• In composite or sub-tropical humid type climate the S/V ratio should be as low
as possible as this would minimize heat gain.
• Analysis:
• The Surface Area to Volume Ratio can be reduced further by using a domical or
vaulted roof & also further reduce direct heat gain.
• A vault roof mud-house with roof made of stabilized mud blocks (composition:
soil, sand, lime/cement and water) would be very helpful in creating better
thermal comfort.
• The annual heating and cooling energy saving potential of a vault roof mud-
house was determined as 1481 kW h/year and 1813 kW h/year respectively for
New Delhi composite climate. The total mitigation of CO2 emissions due to both
heating and cooling energy saving potential was determined as 5.2 metric
tons/year. A vaulted roof would also increase the attic area, which can act as a
thermal buffer and help in thermal insulation both during summer and winter &
also encourage convective cooling at night. Source: Arvind
Chel,G.N.Tiwari(2009), Case study of vault roof mud-house in India, Thermal
performance and embodied energy analysis of a passive house , Energy, Volume
86, Issue 10, October. (An original research article) Pages 1956-1969.

16. Surface Area to Volume Ratio(S/V)
Improved thermal comfort in vaulted roof building made of stabilized mud blocks (composition: soil, sand,
lime/cement and water) (east west orientation)
SEMI-HEMISPHERICAL SPACE IN BETWEEN VAULT ROOF CAN ACT AS A THERMAL
BUFFER. ALSO OPENINGS IN VAULTED ROOF CAN ALLOW FOR CONVECTIVE COOLING
AT NIGHT BY ALLOWINGS WARM AIR TO ESCAPE & ALLOW COOL AIR FROM OUTSIDE
COOLED SURROUNDINGS TO ENTER.

17. 3. Ventilation
• The portion through which cool air
at night could come in at the top
portion of the roof and through
which warm air can go out by
convective process has been
blocked in this particular hut due
to rain water coming inside the
hut during rains.
• This causes lack of ventilation in
summer and convective air flow at
evening and night. A probable
solution is to let the openings
remain and cover them by
bamboo mesh like surface to stop
rain water coming in monsoons Ideal nocturnal ventilative cooling carried out
and increase the overhangs. with small gap to allow air-flow.

18. The above graph generated through Ecotect software for the period from 1st January to
30th June shows, heat gain and heat loss sources. Whereas heat loss is showed through
be mainly through conduction (95.5%), the heat gain is showed to be through a
combination of ventilation/air movement (69.9%) and conduction (28.4%),
validating the need for convective ventilative cooling at nighttime in summer for loss of
heat gained during the day.

20. passive heat gains breakdown in studied hut(10th May-10th
June)

21. model hut-different temperature gains - sources

22. 4. Building Materials
• The building material for the walls is mud (U Value 3.44
W/sq m K) and the roof material is Mangalore Tiles. The U
value for thatch is 0.35 W/sq m K & the U value for
Mangalore Tiles is 3.1 W/sq m K.
• Analysis: Though U value of Mangalore/Clay Tiles and
khapra used is not that high, the insulating property of
thatch is much more, as its U value is even lesser. So in
summer, it keeps the inside of the hut even cooler than
clay tiles do. The disadvantages with thatch can be
mitigated with modern day industrially improved hatch
use.

23. Thatch…
• Modern day thatch treated and improved
industrially can also be used for mass use
in rural areas, being low cost and having
very good thermal properties.
• Thatch is a natural reed and grass which,
when properly cut, dried, and installed,
forms a waterproof roof.
• The most durable thatching material is
water reed which can last up to 60 years.
A water reed thatched roof, 12 inches (30
cm) thick at a pitch angle of 45 degrees
meets the most modern insulation
standards.
• The U-value of a properly thatched roof is
0.35 W/sq m K, which is equivalent to 4
inches (10 cm) of fibreglass insulation
between the joists.
• Only in the last decade have building
codes begun to demand this level of roof
insulation. Yet, thatch has been providing
insulation since much longer.

24. 5. Shading
• There is no shading except for the
projection of the roof. Due to the
high solar elevation angle around
noon time during the summer
period, solar radiation on south-
facing facades is lower and direct
sunlight is easier to shade.
Shading is needed at daytime, in
summer. (specially from 10 AM-
3:30 PM)
• Analysis: If shading is increased
by having greater eave
projections and also sunken
window or chajjah then heat
gained can be considerably
reduced.
Thermal Comfort at 9 P.M, 1st June at night (Ecotect simulation)

25. Thermal Comfort at 12 Noon, 1st September (Ecotect
simulation)

26. RESULTS OF OCCUPANT-SURVEY-MERITS & DEMERITS
• The occupants of the hut moved outdoors during the evenings in summers because
of air movement; air movement inside the house was very less. This further
necessitates the use of nocturnal ventilative cooling carried out with small gap to
allow air-flow through slit like openings in the roof with suitable eve-projections.
• Despite spending most of their time indoors, washing, bathing, drying of clothes,
praying were done in the courtyard early in the morning when the temperature
outside was cooler than in the afternoon.
• The users slept inside the huts throughout the year.
• Occupants of the entire hut felt more comfortable all day inside the house during
summer because it was relatively cooler inside than out.
• Some occupants said temperature was most uncomfortable in peak summer and
peak winter. They also felt humidity and lack of air movement were uncomfortable
in summer & sometimes in monsoon.
• Occupants of some huts said that the rainy season was the most uncomfortable
season.
• Temperature measurements results indicate that the selected hut exhibited lower
ambient temperature than outside during the day and a marginally higher ambient
temperature at night.

27. More Changes that can be made in existing hut-earth
berming

28. OBSERVATIONS
• The Mud house studied reinforced the fact that mud as a building envelope
keeps the inside of the hut cooler in summer. However the cooling effect of
these traditional mud houses can be further improved and living conditions
inside the huts improved by proper design considerations like proper
building orientation, surface-volume ratio minimisation, creating vaulted
/domical roof mud-house and having proper openings in roof which guard
against water ingress of huts to facilitate nocturnal ventilative cooling, etc.
• Modern day industrially improved thatch can be used with all the good
thermal properties intact and the disadvantages of thatch gone.
• More research and study is needed as to how to increase build-ability and
durability of mud houses along with doing away with certain negative
aspects commonly found in mud houses like high humidity during
monsoons, fungal growth & vegetation growth in mud and negative
properties of hatch to be mitigated.
• Temperature measurements results indicate that the selected hut
exhibited lower ambient temperature than outside during the day and a
marginally higher ambient temperature at night. This needs to be
corrected.

29. OBSERVATIONS..continued
• 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, Deccan Plateau,
etc. However the region Jharkhand with its sub-tropical humid
climate or 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 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 and government initiatives and loans/grants.

30. REFERENCES
• 1. Krishan Arvind, Baker Nick, Yannas Simos, Szokolay S.V. (2001), Climate Responsive
Architecture – A Design Handbook for Energy Efficient Buildings, Tata McGraw-Hill
Publishing Company Limited, New Delhi.
• 2. Olgyay Victor (1963), Design With Climate- Bioclimatic Approach to Architectural
Regionalism, Van Nostrand Reinhold, New York.
• 3. Majumdar Mili.(2001), Energy-Efficient Buildings In India, Tata Energy Research
Institute, Ministry of Non-Conventional Energy Sources.
• 4. Arvind Chel,G.N.Tiwari(2009), Case study of vault roof mud-house in
India, Thermal performance and embodied energy analysis of a passive house ,
Energy, Volume 86, Issue 10, October. (An original research article) Pages 1956-
1969.
• 5. Garg H.P, Sawhney R.L (1989), A case study of passive houses built for three
climatic conditions of India, Solar & Wind Technology, Volume 6, Issue 4.
• 6. Gautam Avinash(2008), Climate Responsive Vernacular Architecture: Jharkhand,
India, Masters Of Science Thesis, Department of Architecture, Kansas State
University, Manhattan,Kansas.
• 7. Uthaipattrakul, Dh. (2004). Mud-house construction technique. Building the
house with mud. Suan-ngarn-mena Press, Bangkok, 27-50.