Vernacular Eco-ArchitectureSARTHAK KAURA

Adobe brickmaking

20% - 40% clay content is ideal for making adobe bricks. The top soil is not used for making bricks. The soil is composed of molecules of sand, silt and clay. The brick mixture consists of soil, small gravel and stone, water and dry pine needles. It is as per the Apollonian Theory that the brick is held together and moulded once its dry.

Bricks are made using wooden moulds. The mould is wetted, the mix is thrown inside, patted and the top is levelled. The mould is then lifted and the adobe is left on the ground. It is allowed to dry in the sun and turned to allow all the surfaces to dry. It is then ready to be used or stored. The mix has to be just the right consistency – if it is too wet, it will slouch after the mould is removed. If too dry, the mould will not slide out.

a) Throwing of the brick mix into wetted mould.b) Compacting and pressing mix into the mouldc) Brick making site – adobes laid as close to each other as possible, left to

dry

d) Smoothening of the surface to remove excess mix and making of frog

e) Lifting up the mould gently by holding diagonal corners.

f) Adobes drying in the sun

Adobe bricks being mould casted on the flat ground, on

the left it is being directly casted on ground whereas on the right, it is being cast on a

piece of slate (20in x 11in)

Adobe bricks are layed on ground and each face is turned everyday

so that it dries from all sides. It takes 2-3 days for the adobe

bricks to dry if there is constant sunlight. The bricks are layed

with minimum spacing to cover minimum area so that maximum

bricks can be accomodated.

The mud for the adobe bricks isgenerally procured by digging and

flattening the terraces on which the structure is built.A similar

terrace being cleared and simultaneously the mud being used to make the bricks and

the terrace being used to dry the bricks.

Earth plaster work and earthen renders

Pushpaji our local staff at Dharmalaya Institute working with and guiding a group of volunteers to pug and mix

the sifted mud properly with gobar. Pugging of the mixture and allowing the seepage of water in the mud particles is one of the most vital procedures of plaster

making processes.

Minna using the sifting arrangement which composes of a fine/course wire mesh fitted in a

wooden frame and two bamboo poles are used to support it at a suitable inclinatrion. A piece of slate

is used to rub the soil on to the sieve to sift it.

Visible difference between the sifted and non- sifted mud is evident. All the small

particles of stones are separated from the mud. The particles of stone are a hindrance while doing the finer coats of plaster. The

coarse mud is used in the garden.

The external plasterwork being done. The external base coat plaster layer is about 0.5 inches thick. This layer is not fine as it needs to be course to provide a rough surface for the second of the plaster to hold on to it.

Bamboo scaffoldings are made while constructing the walls so as to provide a surface while making the roof and also

while plastering.

Pushpaji who is a trained mason, is doing the interior plaster work. In the picture we can see all the tools and

paraphernalia used for doing the plaster work : trowel, float, water mug, pan et al. The surface is made wet for the mud plaster to easily hold onto the

wall.

Mud plaster:

Three layers of plaster are usually applied to the adobe walls. The first layer has a 3:1 proportion of soil and sand respectively, with the addition of linseed (alsi) husk, which is grown locally. The linseed husk adds insulative properties, water repellent properties and helps the mix to bind well. The soil used is passed through a coarse grade sieve with a mesh of size ???. This process is called sifting, sieving or screening. It enables the removal of large stones and allows only smaller pieces of gravel to pass through. The mixture of soil with gravel, sand, husk and water is then pugged and allowed to rest for a minimum of two days. Any uneven or irregular surfaces in the masonry are corrected during the application of the base coat of plaster. Hence it is the thickest layer.

After the first layer is applied, it cracks on drying, above which the second layer is applied. This layer has the same proportions of soil and sand with the addition of cow dung (gobar) in the ratio of 7:3 (mud : dung). The soil used for the second coat is sifted through a finer mesh of size ???, eliminating all stones and gravel. After pugging and resting, the plaster is applied. This coat is much thinner than the first.

The final layer is done with a coating of fresh cow dung, to which natural or synthetic glue is added. Water and cow dung are mixed together to form a thick liquid, and applied onto the wall surface with a cloth. This is traditionally called ‘lepai’. Alternatively, paper pulp can also be used for the final layer which is equivalent to gobar and requires less maintenance.

An intermediate layer after the second layer may also be applied. It consists of the addition of the water in which linseed husk has been soaked for at least 2 weeks. The oils from the linseed husk add water repellent properties to the plaster.

Gobar slurry being mixed into the sifted mud for second coat

plaster.And small particles of stones being picked from the plater

mix

A final coat dung plaster composed of turmeric and lime pigments being

plastered onto the walls for achieving a tint of colour.

Circular patterns and arcs and strokes being

made on the wall .

Circular strokes of cow dung plaster with colour pigment being done on the wall..

Circular patterns of cow dung plaster being done on the mud floor, using a small piece of cloth. The cloth is small as it drips less although it takes more

time to although.

e a r t h b a g p o r c hThe entrance porch for a cottage at the Dharmalaya campus was constructed using earthbag technology. Since it was to be of a low height and non structural, no foundation trench was required. The courses of earthbags were started at ground level. It was a total of 5 courses, with a proposed slate flooring on top. The outer faces are covered in mud plaster and turf.

Course and sandy yet little moist mud being filled in the

ACC cement bags till they are 2/3rds full.

Courses of earthbags being laid on the two lines of barbed wires which are spanned on te coarse to hold the above coarse of bags and act like mortar.

Once the courses earth bags are laid,

they are compressed using this wooden

tamper.

The courses of earthbags are staggered so as

to avoid continuous

vertical joints.

Completed plinth wall with 5 curses of

earth bags

Bricks or stones are used to flatten out the barbed wire so that the earthbags can be laid

on it.

Glass and soft/hard plastic

waste being dumped in the

Since the plastic is compressible, it is topped with rubble.

Mud is added on to the top of the rubble to

level the plinth.

Sifted mudis pugged an mixed and allowed to sit for a couple of

days to make this cob mix.

Balls of cob are made and plopped onto the earth bag wall to form a thick layer of 1 inch.

Turf or patches of grass with roots and mud on it is dunked in water

and slapped onto the cobbed wall, so that it

holds onto it and covers the entire wall.

Once the entire wall is covered in turf, it is watered until it

holds roots into the cob.

s l a b r o o f f o rs t o r e r o o m

Bamboo purlins laid on the timber beam . A

mat of chachra is being spread on the

bamboos, which acts as scaffolding.

Timber beams, bamboo rafters and

chachra from beneath the slab

Chachra being spread and the chicken wire mesh being nailed to the chachra for the ferrocement slab.

Carpenters laying the chahchra onto the

the bamboo purlins.

Rrocement One brick tall wall constructed for

curing the freshly casted ferrocement

slab.

Slate flooring is a technique introduced by Didi Contractor in her neo-vernacular style approach.

Materials used: Slate tiles (find out dim and thicknes)4” wide glass strips, cement, sand, pigment additive for cement

Procedure for laying slate floor:

Flooring is done only once masonry and installation of the roof has been completed. The area to be floored is levelled, and soling is carried out. Soling consists of stacking stones on their vertical edges. Gravel is spread to fill interstitial gaps and a dpc is laid next. Above the dpc, a PCC bed (with cement:sand ratio 1:6) is laid, taking care to maintain the necessary slope of the floor. Glass strips are placed while the cement is still wet, as per the required design. Finally, the slate tiles are placed and pressed gently into place. Rich cement is spread in the space between tile and glass. At Dharmalaya, a green pigment is added to it for aesthetic reasons.

Finishing of the floor:Slate tiles are first scrubbed clean using a locally available stone and a coat of clear varnish is applied. Since the surface of the slate is uneven, the varnish fills the gaps and makes the floor easier to maintain.

Advantages of using glass strips:-Cement expands and contracts with thermal changes, which can cause cracks in the floor and make it more susceptible to moisture and damage. The glass stripshelp fragment the cement surfaces and thus reduce cracks.-When a cement floor of large area is being laid, unsightly joints appear on the surface as laying of the cement is done in batches. To avoid this, glass strips are incorporated as part of the design, improving aesthetics as well as making the cement laying procedure easier for masons.- The strips act as a reference to check if the slope of the floor is being correctly maintained.- In case of damage, it is easier to replace a tile without disturbing the surrounding ones because of the glass strips

s l a t e f l o o r i n g ( c h a k k a f l o o r i n g )

Material required: Centre-line drawing of the proposed structureMeasuring tape, string (sut), right angle

(guniya), pegs/stakes, pick-axe, shovels, compass, spirit level, lime powder etc.

The wall thickness executed for adobe masonry in Dharmalaya Campus is generally 18” and the wall thickness for the wet blocks (baked brick masonry) is 9”. The plan went through went through a series of modifications as per the shape of the contour and the existing trees so as to cause minimum damage.

The datum was established in the beginning and the extremities of the proposed structure were roughly located to check the feasibility of spanning the building across the contour. The plan was adjusted as per the site parameters.

The detailed centre-line procedure was begun. The Pythagoras’ Theorem was used at every junction to confirm the accuracy of the right-angle. The Guniya and the Thread (Sut) were used for connecting straight centre-lines of the walls. The Lime Powder was used to mark the mark the straight lines.

The offsets were marked on the either sides of the centre-lines as per the wall thickness and load carried by the walls. The walls bearing the load of the first storey, were 3 feet wide and whereas, the rest trenches were 2 feet wide.

l ine out forduplex cottage

e x c a v a t i o n o f t r e n c h e s

Above the plinth band up to the sill level, stone masonry walls are constructed. Above the sill level the walls are built in Adobe. Adobe walls are built out of earth excavated from the site during levelling. Mud is mixed with straw, sand and clay to balance the composition of earth and is placed in the sun to dry. Usually bricks of size, 12 inches x 6 inches x 3 inches are used for 18 inch walls ; however different sizes are made for different applications as well. For example, Queen brick is used for window ledges to bring in more light.

Wooden horizontal bands are a common feature in the buildings that survived the major 1905 earthquake and are majorly seen in the in the Kath Kuni style of architecture which is seen in the northern part of Himachal Pradesh. In spite of Kangra region being densely forested, the wood is excessively felled by the Government for export purpose. Therefore Didi Contractor has substituted wood for reinforced concrete bands in the adobe brick walls. These horizontal bands are tied together with vertical reinforcements built up within the main load-bearing corners. This forms the protective skeleton embedded and keyed within brick work of the adobe buildings.

20% - 40% clay content is ideal for making adobe bricks. The top soil is not used for making bricks. The soil is composed of molecules of sand, silt and clay. It is as per the Apollonian Theory that the brick is held together and moulded once its dry.

Large particles of stone need to be picked out while making the brick mix. Dharmalaya Institute is situated amidst a pine forest; hence dry pine needles are abundantly available. The needles are added to the mix, while pugging it. The needles reinforce and give the brick additional tensile strength. The pugging is important as it allows the water molecules to penetrate deeply, in between the mud particles. The mixture should be allowed to rest as, it takes time for water to percolate at a molecular level.Tools used:Plumb bob, water level pipe, trowel, hoe, bucket and tumbler.

Steps for constructing an adobe wallThe surface on which a new course of adobe has to be laid is first wetted. A layer ofmud mortar (~ 1” thick) is spread on it, in gradual patches. Corner bricks for theexternal face of the wall are laid first. When the adobes are placed on the spread mortar, their rougher face generally faces up and this is maintained as a constant throughout the masonry. They are gently jostled into place, causing the mortar to spread completely on the entire face. Their plumb is checked using a plumb bob and a string is stretched between them. Subsequently, adobe blocks are laid in the desired bond pattern, taking care that the blocks do not touch the string, but are as close as possible to it. This is done to maintain an accurately vertical surface. A water level pipe is used to check the accuracy of the horizontal level of the course. Once a course is complete, the gaps between adjacent adobes are filled in with mud mortar. The process is then repeated.

A d o b e b r i c k w a l l s

The hilly regions of Himachal, experience a lot of rain and also some snow, so it is very important to have a roof that would address the climate and weather conditions.So, an inclined roof is prevalent in most of the regions of Himachal.

The roofs used at Dharmalaya are either single lean-to or double lean-to roofs, depending on the span of the structure. Didi Contractor keeps the inclination of her roofs from 30 - 45 degrees, with steeper slopes towards the north and the introduction of dormer windows and skylights.

P i t c h e d r o o f f o r c o t t a g e

The components of Roof :

Timber beams :The most economical length of the timber beams is about 10 feet. Pine wood is generally used for this purpose as, it is abundantly available in the near-by forests.

The tie beams in the trusses for large span roofs or the edge sleepers (dhansa) which rest on the walls to distribute the load. Generally a piece of slate or broken glasses are put at the junction where the timber member and the wall meet, to distribute load evenly. The common beam size is 10 inches x 4 inches for ceiling slabs, but for the trusses, it is -

Rafters:The rafters are of bamboo or sometimes, hollow steel pipe sections for the ceilingroofs. The rafters are placed on the sleeper which rests on the wall and the ridgebeam at the top. The bamboo rafters are nailed to the respective junctions at the ridge and the sleeper using 4 inch nails.

Ferrocement:

The ferrocement slab comes on the Chachra, it function basically to improve the strength of the roof and also make it entirely leak-proof. The ferrocement slab is about 2-3 inches thick and has a chicken steel wire mesh, in it- which is tied and nailed to the chachra. the proportion for cement : sand is 1:6. Sometimes mud is mixed with the cement to minimize the use of cement.

Purlins:the purlins are basically pine wood batons which are nailed into the ferrocement slab at an interval of 12-13inches. the battons hold the slate tiles, which are inturn nailed into the purlins.

Procedure:

The seasoned and treated bamboo rafters are first mounted onto the walls and the gable wall construction is done around the wall edges. The Chachra is mounted and nailed onto the rafters. Chicken mesh is tied to the Chachra. The cement concrete slab is cast onto the Chachra scaffolding. Wooden purlins are nailed onto the ferrocement slab. The slate tiles are nailed onto the wooden purlins the last.

Bamboo treatment:The purpose of the bamboo treatment is to reduce the pest and termite and other bore insect damage. The insects attck the bamboo for the starch in it. Hence, traditionally the bamboo is harvested on the new moon day when the photosynthesis cycle is such that there is minimum starch in the bamboo trees. There are two traditional treatments for removing the traces of starch from the bamboo poles:#1 Leaving the bamboo poles in a "kihl" which is a stream of flowing water for about 28 days.#2 Smoking the bamboo twice daily for 2-3 weeks in a bamboo kiln. Dharmalaya Institute has its own bamboo kiln where the bamboos are treated.

Fibre glass sheets and Onduleum (recycled fibre glass sheets) are used for roofing where there is a requirement for light.Fixed glass or Fibre glass sky lights are also provided in the roofs.

The overhangs for the openings are designed with fibre glass roofing to get the light inside thebuilding and protect the building from the rains.

Roof is the major component that is responsible for temperature exchange in a building. Insulating layers of rice husk and mud along with ferrocement does help in providing additional insulation.

Wattle and daubCoats of slaked lime

being applied onto the bamboo weave mats

(kelta).

A timber frame with diagonal braces and a post, with a bamboo

weave mat nailed from the outside, later the both faces to be cob

plastered.