Low cost house in an urban environment. An attempt to bridge the gap between vernacular and modernity

1. AN ATTEMPT TO BRIDGE THE GAP BETWEEN VERNACULAR AND MODERNITY
LOW COST HOUSE IN AN URBAN ENVIRONMENT
Residence for Late Shri Sanat Mehta, Gandhinagar -1994
Shirish Avrani Architect - Planner

2. Shirish Avrani
Architect – Planner
Mob : 9004454478
shirish.avrani@gmail.com
I am extremely grateful and indebted to late Shree Sanat Mehta who gave me free hand
for undertaking such unique project of building with mud as well as caring out various
innovative technologies. He always encouraged me for experimentation of several
innovative design ideas at various occasions.
I was fortunate to have person like him as my guardian and guide.
This was a pioneering initiatives working with stabilized
mud blocks with non-erodible mud plaster using tar primer
as well as use of Mangalore tiles filler slab technology in
Gujarat. (1994)

3. Late Shri Sanatbhai Mehta, a political leader and a social
worker had a deep loving association with the tribals of Gujarat.
He expressed his view to build a tribal house in his land at
Gandhinagar – a state capital. It was a great challenge to adopt
elements of design of tribal house and construction technology
to suit urban environment and contemporary life style.
A simple person “ Down to Earth “
• Ex. Finance Minister of
Gujarat
• Ex. Housing Minister of
Gujarat.
• Ex. Member of Planning
Commission.
• Ex. Member of Parliament
• Ex. Chairman of Narmada
Sarover Project
Late Shree Sanat Mehta
1925-2015

4. Objectives
▪ To understand the application of Appropriate technology through live experiment
▪ To have demonstrative effect among other elite class of people – that low cost
technology is not only for poor but also for high class of people. It is a “way of life” and not
the compromise.
▪ To bridge the gap between vernacular and modernity. A step towards Responsible
Architecture
▪. To identify problems and constrains of :
▪ Convincing the client
▪ Construction process
▪ Contractor
▪ Availability of materials
▪ Finding Laborers – training
▪ Construction time
▪ Maintenance problems.
▪ To experiment innovations like non erodable mud plaster, filler slab etc.
▪ Resistance against natural calamities like earthquakes and cyclones.
▪ To work out actual cost of construction.
▪ To understand and visualize aesthetics of simplicity

5. Tribal Architecture is an Architecture of commonsense:
The South Gujarat tribal house is having a different design context. It has structural grid of 8’ X
11’ wooden post beam system. Forming left bay for cattle, middle bay of living and storage and
righ bay for kitchen and sleeping areas. Roof is made out of country tiled pitch roof. The room
spaces are divided with flexible partition of bamboo mat with mud plaster or wattle and daub
walls. This gives a great flexibility for various permutations and combinations of spatial
arrangements within a structural grid. This basic concept of space making was carried forward to
suit the requirements of contemporary life style.
Typical tribal house. The column located at kitchen is skillfully eliminated for getting free space by
removing opposite column, creating counter balance cantilever action.

6. Transformation : Adaptation of composite structural system. Wooden columns replaced by precast
RCC column - a tribal house of South Gujarat

7. Design Considerations – Adaptation of Vernacular in urban Context.
The principles of vernacular Gujarat tribal architecture was adopted and modified to suit
with urban environment, keeping in mind the life style and values of the owner. The Plot
area comprises of 330 sq.m. (15m X 22m) having East-West orientation. The total built-up
area 171 sq m with ground floor area of 104 sq m. The axial entry is provided which
leads to central open courtyard, around which all other activities are planned. The bed
room is at the rear end for access to South-West wind direction, along with kitchen and
store with a separate service yard are provided.

8. The first floor consists of two bed rooms with attached bath and terrace. An umbrella
(Chhatri) is provided in terrace indicates and emphasis the main entrance bellow.
The wooden columns were replaced with cheaper than RCC, circular steel posts
(available from scrap of Alang Ship breaking yard). The intermediate floor and
sloping roof of Mangalore tiles filler slab was constructed for better insulation and
cheaper costs. Walls are made of stabilized mud blocks, with non erodable mud
plaster. Doors and windows were made with pre-cast frames and Nuwud MDF
shutters.

9. View from first floor- Rose window
made from empty bottles
Columns made out of scrap steel
pipes, available from Alang Ship
breaking yard.

10. The open-to-sky central courtyard surrounded by vestibule, living room, dining area with stair and
swing makes it transparent dynamic living space.

11. Dining area. The exposed ceiling
of Mangalore tills filler slab is
visible.

12. THE CONSTRUCTION PROCESS:
1. The Compressed Soil-Block Making:
1.1 Tests and Mixing
Ribbon Test to Check For Soil Plasticity: Roll a small handful of soil (with just enough water to
make it stick together) into a ribbon of ¼ to ½” diameter. Check how long it can be rolled before it
breaks off. In this case, 4” length is sufficient.
Ribbon test for Soil
Plasticity

13. Optimum Moisture Content Test to Check for Maximum Density:
Make a ball of soil of 2 to 2.5” diameter, and drop it from a height of 3.5 to 4’. If the ball does
not fall apart, it indicates too much of moisture cointent, and is therefore not suitable for block
making. If it collapses into a patch of 2’ to 3’ diameter, then moisture content is optimum.
Too much of moisture
content keeps the soil ball
intact
Optimum moisture content –
A spread of 2 -3 feet

14. Stabilizing the Soil:
Cement, cement and lime, lime, bituminous tar products and molasses are some of the
stabilizers used to prevent soil softening when it absorbs moisture.
Since soil in Gnadhinagar is red, sandy lloam, 4% of cement was added by volume, over the
soil and then it was manually mixed. If mixing is not done thoroughly enough, the blocks will be
defective .
Mixing soil with
cement stabilizer

15. 1.1 Making the Blocks
ASTRAM the block-making machine developed by ASTRA (Application of Science and
Technology for Rural Areas – Bangalore), required 5 people to produce about 400 blocks per
day, each block being 9” X 7” X 5”. The procedure is as under:
Fill the mould with
prepared soil with the
help of a scoop;

16. Staking and drying blocks in the shade.

17. Curing the blocks for a fortnight
Comparision of good and bad
blocks:
The right hand side block shows the
uniform mix of soil and cement. The left
hand side blocks are bad blocks in
which mixing of earth and cement is not
thoroughly done. This may affect the
strength of the block.

18. Compressive Strength Test for Stabilise
Mud Block:
Stack blocks up to a height of 6 feet,
keeping the base blocks slightly apart. A
crack should be avoided in the base block
in order to ensure good construction.
Field test for compressive strength
Test for Comprehensive S
of Block:
Stack blocks upto a height
base blocks slightly a part.
avoided in the base block i
good Construction.
2. Erecting Column
Scrap steel pipes from the
Yard are comparatively c

19. 2. Erecting Columns
Scrap steel pipes from the Alang Ship-Braking
yard were comparatively cheaper than market
ones, besides being stronger and joint less. 4.5”
diameter pipes of 4-5 mm thickness were used as
a supporting structure.
2.1 Footings
RCC footings were provided for steel pipes, while
the rest of the foundation were made out of
conventional brick masonry.
2.2 Fitting the Bars with Footings
Base plates were welded with projected bars for
the column footings. The upper part of the column
was provided with holdfasts, to be inserted into
beams
The erection took only three days, much less
then RCC column.

20. 3. Mangalore Tile Filler Slab Roof
The concrete below the ‘Neutral Axis’ of the slab is redundant and can easily be replaced with other
cheaper material like tiles, bricks or coconut shells, on which a thin reinforced slab is cast.
Construction steps follows :
• Formwork similar to RCC slab, spread with the engine oil .
• Manglore tiles immersed in water for 24 hours before use.
• Reinforcement bars placed at 18 “ X 12 “ C/c distance (or as specified in design) in case of 10
feet slab span, Main bars (10 mm dia.) were placed along the short span and 8 mm dia. bars
along the long span.
• Negative bars are projected up to 2 feet at the junctions of walls or beams.
• Mangalore tiles placed as filler materials, one above the other, in the gap between reinforcement
bars
• Concrete mix of 1:2:3 is manually done and then vibrated to avoid honeycomb.
• Proper curing for about seven days with water on the slab.

21. Mangalore tiles placed as filler materials, one above the other, in the gap
between reinforcement bars

22. Concrete mix of 1:2:3 is manually done and then vibrated to avoid
honeycomb.

23. 4. Precast Window / Door Frames
Pre-cast door window frames were used for entire house .The precast members were
assembled on site and erected along with the walls. Safety bars act as holdfasts. Shutters made
out of Nuwud MDF panels.
▪.The RCC frames are cost effective and give protection against termite.
▪.It is not affected by weather change.

24. 5. Construction of Walls
• After erecting steel column and filler slab, the 7” thick mud wall were constructed with cement
stabilized-mud mortar.
• 8% cement, by volume (double the amount used for the blocks) was used for the mortar,
because the strength of mortar has to be more than building blocks.
• Volume of one block (9”X7’X5”) is equivalent to volume of three bricks. Besides, no requirement of a
header-stretcher course for bonding, resulted in faster construction

25. Non erodible mud plaster – Developed by CBRI Roorkee – 15 part mud : 5 part tar :1 Part kerosene-
mixed together and applied on mud walls.

26. Non Erodable Mud Plaster:
Tar primer, produced by the Tiki Tar industry
found to be suitable for stabilizing mud
plaster, because it did not require heat
treatment to melt, or addition of kerosene to
dilute.
Primer is soluble in water and easy to mix
with mud. It is mixed in the ratio of 1:15 by
volume.
Test:
Soil mixed with tar primer does not
dissolve, like normal soil , in a
glass of water even over a long
period of time.

27. Preparation of Wall Surface for Mud plaster:
▪. Water is sprinkled on the wall before plastering;
▪. Non –erodable mud plaster was applied with trowel, like a cement plaster.

28. Cupboards and built-in beds were constructed out of Kotah Stone. The shutters and sliding
drawers were made out of NuWUD

29. The creative ‘lipan’ is done
with cow-dung to finish the
walls

30. B – ENERGY PERFORMANCE OF A PRE-FAB CONCRETE
A – ENERGY PERFORMANCE OF A MUD-BRICK HOUSE
MUD-BRICK HOUSE PRE-FAB. CONCRETE HOUSE
ENERGY PERFORMANCE OF AN IGLOO
FIGURE 1 : Daily variation in the inside air temperature of an igloo
(at sleeping platform level) under typical arctic temperature
condition (From Fitch, J.M. and Branch. D. P., Sci. Am., 203. 6.
1960. Copyright 1960 by Scientific American Inc. All rights
reserved).
ENERGY PERFORMANCE OF AN ADOBE HOUSE
FIGURE 2 : Daily variation in the inside air temperature of an adobe
house under high daytime temperature condition (From Fitch, J.M.
and Branch. D. P., Sci. Am., 203. 6. 1960. Copyright 1960 by
Scientific American. Inc. All rights reserved).
FIGURE 3 : Comparison of the inside air temperatures in a mud-brick room and a prefab concrete room. (A) Mud-brick room (B) Prefab concrete room.
(From Cain. A., Afshar. F., and Norton. J., Architectural Design, 4/75, 207.)
IGLOO

31. Comparative Cost Analysis
Components Conventional
Technology
Non-
Conventional
Technology
Percentage
Saving in
Cost
Other
Advantages
Masonry Work Brick Wall Stabilized
Mud Blocks
with 5%
cement
53 % ▪ Better
insulation
▪ Biodegradable
▪ Energy saving
▪ Labour-
intensive
Column RCC Column 4.5”dia steel
pipes
11.26 % ▪ Fast
installation
Slab RCC Mangalore
Tiles RCC
Filler Slab
14.41 % ▪ Better
insulation
▪ Light in weight
▪ Saving in cost
in case of
RCC structure
Doors Teak Wood
frame &
Panel shutter
RCC Frame
Nuwud
Shutter
27.88 % ▪ Eco-friendly
Windows -do- -do- 31.34 % ▪ -do-
Plastering Cement
Plaster
Non –
erodable
Mud Plaster
47.14 % ▪ Decorative
texture is
possible
* The property tax collected by the local authority can be reduced as the cost of
the building is comparatively lesser than the conventional structures.

32. Appreciation letter from Shri
Hasmukh Shah, Chairman of
Gujarat Ecology Commission
and Ex. Chairman of IPCL

33. Appreciation letter from
Ex. Prime minister Late Shree
Chandrashekhar Ji.

35. To
Dear Shirish
I am glad to see your sketches and photos of
your family and other articles.
It is good to break boundaries so keep doing.
All the best wishes for future success stones.
Doshi
30 May, 2019
Ahmedabad

36. Sustainable architectural practices are inbuilt in tribal culture since childhood.