HUDCO CONSTRUCTION TECHNIQUES

C O N T E N T S :- I N T R O- M U D B L O C K S T R U C T U R E- W AT T L E A N D D U A B U N I T- R AT T R A P B O N D B R I C K C O N S T R U C T I O N- B R I C K P A N E L H O U S E- B A M B O O H O U S E- F E R R O C E M E N T C H A N N E L U N I T- S T O N E P AT T I C O N S T R U C T I O N

MUD BLOCK STRUCTURE• Traditionally ADOBE technology of unburnt sun-dried bricks made out of mud was used for building walls, over

many centuries in the past. The ADOBE brick making process is converted into block making process here.• Mud block making is very simple. By using a small box or a mould, blocks are made out of fine mud mixture. • After drying blocks can be stored until they are required for construction.• It is an economical option for millions of homeless people to build a small home without restoring to use of

energy intensive material.

MAIN FEATURES:• Masonry with mud blocks made with locally available earth – a cost effective method.• One side terracotta tile faced mud blocks to make the external wall face water resistant.• Cost effective and eco-friendly fly ash brick used for columns with vertical bars.• Arch roofing using conical tiles with broken tile chips for water proofing the roof.• Seismic features- horizontal plinth and lintel level bands.• Bamboo panelled door and window shutters.• IPS flooring with colored oxide.

DEVELOPMENT OF MUD BLOCKS:• Good durable walls are expensive and also difficult to build.• It was impossible to build a mud wall with locally available black cotton soil because it could not last long.• CVS of Wardha solved this problem by providing a tough, non-erodible, terracotta tile support to the outer

portion of the wall that is built with locally available soils.• CVS then used burnt clay tiles keyed into the mud block at the green stage itself. The rear portion of the tiles was

given a protruding shape of dovetail to fix it into the wall tiles firmly.

CONSTRUCTION PROCESS

FOUNDATION • The site being rocky and sloping, un-coursed rubble masonry with boulder murrum filling is laid to prepare a flat

ground.• At plinth level, 100 mm thick RCC Damp Proof Course is provided to counter earthquake pressures. Sill level is

taken at 900 mm i.e. almost a metre and finished by PCC band.

SUPERSTRUCTURE

FLY ASH BRICK COLUMN• Fly ash brick columns are constructed as per design specifications over the plinth band. The size of the column

may be taken as 230 X 230 mm. After completion of brick columns, one RCC lintel band of 230 X 200 mm size is cased over the columns.

WALLING• For internal walls, mud blocks of 300 X 230 mm size are made without terracotta tiles.• Mud block wall is rain proof and rodent proof. No need for any other binding material

ROOFING• No steel and wood is used for roofing. The roof consists of a series of arches to be placed as a formwork from

the conical tiles made out of burnt clay inserted into one another.• Cement mortar of proportion 1:3 is applied over the tiles to cover the gaps in between conical tile arches.

WATTLE AND DUAB UNIT

MAIN FEATURES:• Cement is used as stabilizer.• Foundation based on stilts and random rubble masonry.• Flooring of verandah made from locally available wood.• Columns constructed using stabilized rammed earth block technique employing ‘ram rod’ technique.• Walls made of bamboo mats plastered with mud or lime mortar.• CGI sheet roofing over space frame truss instead of wood. Bamboo CGS can be used.• Roof water harvesting shows syntax water tank connected to a cost effective sanitation model.

CONSTRUCTION PROCESS:

FOUNDATION AND SRE COLUMNS• The foundation is in random rubble, except for the verandah which is on stilts.• The soil should be tested for its quality and bonding characteristics and then sieved through a wire mesh.

Recommended mixture of soil and cement is 92-93%: 7-8%.• Steel moulds or wooden frame work are assembled. Homogeneous mixture of sand and cement is poured

in the moulds layers and rammed with a rammer weighing 15-20kg. • For vertical reinforcement in foundation 2-12 mm rods are placed in vertical manner. PVC pipes are placed

around the steel bars and concrete is poured in it.

ASSEMBLING THE STEEL OR WOODEN FRAME WORK

TO HAVE VERTICAL REINFORCEMENTS, PVC PIPES ARE PLACED AROUND THEM

AND CONCRETE IS POURED.

RAMMING OF EARTH IN THE MOULD

REMOVING LUMPS OR STONES BY SEIVING.

MEASURING OF COMPONENTS FILLING CONTAINERS

WALLING• In this technique, mud is used as plaster to cover thin panels of cane, split bamboo or other stalks

that are woven together and held in place by wooden or bamboo posts and beams. This called WATTLE AND DAUB UNIT.

• DAUB is a mix of clay: cow dung, bhusa in the proportion of 10:3:3. Red clay is soaked in water and thoroughly mixed to break down bigger lumps.

• Sand is also added to improve the clay content of the soil. This mixture is kept for one day prior to use. If some coal tar is added to the above mix, it serves as water proofing agent.

• The DAUB mixture is applied simultaneously on the bamboo mat. Ensure that the mud pack is properly compacted within the grooves of the bamboo mat. Allow it to settle for one day before second coating. Give the finishing coat of coal tar.

• ROOFING• Space frame truss roofing is suggested as an alternative roofing system to the normal wooden

frame work with RCC roofing. This roofing can withstand medium intensity cyclonic winds.

• It is light weight and cost effective. The assembling can be done by unskilled manpower also.

• The space frame truss is usually built with simple pipes of 15-25mm diameter with bolting.• It can be built over any span and can be formed in any shape – circular or conical or two slopes or

hipped roofing patterns.• The structure is detachable and can be reused.

• Bamboo mat corrugated sheets are recommended as they are eco-friendly and self -sustaining alternative material.

• Fixing of sheets with J bolts should be done by bitumen washers on both sides to prevent water seepage.

PLASTERING• Plastering can be done in many cost effective ways.• Mud and lime plasters were traditionally used.• Cement mixed with the mud and lime is recommended as a finishing coat. • Crush and sieve dehydrated lime.• Prepare mixture with 50% sand and water, which is kept for 6-8 days.• Stir the mixture and keep it in a covered space to avoid dust.• Mix gugal gum to lime mix before application.

STABILISED MUD PLASTERStabilised mud plaster consists of mud and cement in the proportion of 3:1. This mix gives a smooth and polished finish after the repetitive rubbing process.

ADVANTAGES• Uses natural material• Gives better finishing and saves wall painting cost• Provides thermal comfort• Use of lime is a livelihood promotional activity

FIXING BAMBOO NET ON WALL

PLASTERING WATTLE AND DUAB WALL

ROOF WATER HARVESTING

• The rain water harvesting system has been incorporated.• PVC pipes are laid to collect rain water.• The catchment area of the roof is 31.50 sq. m. and it can collect around 67000 litres of water in

the annual rainfall.• The water can be used for all purposes.

HIGHLIGHTS• The structure is totally earthquake resistant as vertical and horizontal bands are provided.• The space frame truss is light in weight and easy to assemble.• The wattle and daub unit involves use of locally available materials like twigs, wood, bamboo,

etc. PIPES FOR COLLECTING ROOF WATER

TECHNOLOGIES USED

RAT TRAP BOND CONSTRUCTION The rat trap bond construction technology is a cavity walling system, designed to optimise the use of bricks and cement mortar. In conventional wall construction bricks are placed flat, while in the rat trap bond construction technology they are placed on the edges with cavities between two faces. It results in an approximate saving of 17% bricks and 54% mortar. The reduction in overall costs is estimated around 26%. Also, the building is constructed using brick arch foundation, filler slab roofing, brick jallie windows and brickbat flooring technologies.

MAIN FEATURES• Random rubble arch foundation• Rat trap bond wall that saves 25% bricks and cement.• Brick window jallies• Filler slab roof• Non-erodable mud plaster upto sill level.• Use fair face of the bricks in patterns to avoid plastering• Mud and brick bats flooring in different rooms• Kadapa slabs for shelves

Construction process

BRICK ARCH FOUNDATION• Excavate square base as per the design dimensions.• Lay 150mm thick pcc (1:3:6)• Cut soil between square bases as per the design profile. Lay 75mm thick

concrete (1:5:10)• Construct brick arch resting on mud based brick framework. Cure for 4-7

days before removing brick frame work.• Brick masonry arch should be constructed as a monolith

SUPERSTRUCTURE: WALLING• Rat trap bond technique of wall construction provides better insulation

properties. It is as strong as the ordinary solid 9” brick wall. It saves around 25% of bricks and 40-50% of cement and sand.

• The bricks are placed on their edges in 1:4 cement mortar and after the firs layer of bricks is laid, a gap is left between the bricks in the remaining courses. The gaps in the bricks help to create thermal insulation.

LAYING OF BRICK ARCH FOUNDATION

LAYING OF RAT TRAP WALLS

BRICK JALLIE WINDOWS• Wooden windows are costly. 1 sq. ft of a wooden window can cost 20 times the cost of

simple bricks or stone wall it replaces.• A jallie or a honey comb brick or stone pattern is very effective to serve as a window as

they reduce the cost of materials.

ROOF- SLOPING FILLER SLAB• This is a cost effective roofing system for single floor buildings. It is based on the

concept that for a simple slab with concrete below the neutral axis takes no tension and is not of much use and clay tiles can be placed in the slabs to act as fillers.

• The steel in this zone bears the tensile forces while the concrete is retained above the neutral axis, and it can take compressive loads very effectively.

• The air gap between the tiles makes it a good heat insulator and the ceiling look attractive.

• On the rcc roof top, opening are provided to get enough sunlight. These openings are covered with fiber glass to prevent the entry of rain water.

ARCHES• A brick arch is primarily a compressive structural system. The action of compression

develops due to arrangement of bricks.• Parabolic arches are 100% compressive.• Usually for construction flat, semicircular or segmental arches are recommended.• Arches save foundation costs.

HIGHLIGHTS:

• Rat trap bond walling: saves around 30% costs- bricks and cement.

• Window jallies: most economical when compared to windows made out of wood and steel

• Filler slab roofing: saves RCC costs.

INSIDE VIEW OF FILLER SLAB

BRICK JALLIE WINDOW

LAYING MANGALORE TILES AS FILLER MATERIAL

BRICK ARCH

BRICK PANEL HOUSESPECIALITY :• Use of brick panels for roofing.• Prefabricated brick panel and partially pre-cast joists require burnt clay bricks, cement, sand, coarse

aggregate and reinforcing steel as major raw materials.• No major plant, equipment and machinery is required.• The brick panels are durable, leak-proof, fire-resistant, thermal-resistant, less noisy in rains and provide

vertical expansion.• They are very cost-effective and generate employment opportunities in rural areas for masons/labour.

CONSRUCTION PROCESS :

FOUNDATION• The foundation is made with the un-coursed Random Rubble Stone masonry.• Locally available materials are used.• At plinth level, 100mm thick RCC damp proof course is provided to prevent earthquake movements.

CAVITY WALLS• Cavity wall consist of two walls built parallel with a hollow space of less than 4” width between them.• The cavity wall is mainly used in earthquake and flood prone areas.• It protects the inner wall from dampness and cracks due to earthquake vibrations.• The thickness of the outer wall and inner wall may be equal or the inner wall may be thicker (9” thick)

than the outer wall (4” thick).• The cavity should be uniform throughout the height.• To hold the outer and inner walls together firmly, metal ties or specially manufactured bonding bricks are

used. The ties are fixed at staggered places at a distance , not exceeding 1m horizontally and 40cm vertically.

• The bonding arrangement of bricks may be in Stretcher Bond, English Bond, Flemish Bond or English garden wall bond fashion.

ADVANTAGES:• Cavity wall checks the penetration of dampness from outside to inside.• Decreases the heat transmission considerably.• Reduces the external noise inside the building.• The cost of cavity wall is 20% less than the cost of a solid wall having the same thickness.

METAL TIE

CAVITY WALLFOUNDATION WORK IN PROCESS

FOUNDATION BEING LAID

BRICK CORBELS• Brick corbels are bricks projecting from a wall constructed to provide a better appearance to support beams,

trusses, lintels and for openings to doors and windows etc.• The following factors need consideration to ensure the stability of a brick corbel:• Maximum projection of the corbel should not be more than the thickness of the wall.• Maximum projection of each corbel course should be limited to a quarter brick at a time.• Header bond is used for the construction of brick corbels. BRICK JALLIES• The bricks are arranged such that openings are created between them and thus it acts as a natural window. ROOFING• Roofing is done with brick panels, which can be made on site.• The dimensions of a brick panel are 1.10m x 0.53m.• It provides strong, permanent and economical roof/floor consisting of partially pre-cast RCC joists supporting

the pre-fabricated brick panels covered with 35mm thick cement concrete with sustainable reinforcement.• Ideal for low cost houses especially for the economically weaker sections of society in rural/urban areas.

LIST OF TECHNOLOGIES:• ½ brick walling and brick column• Corbelling brick work• Filler slab• Exposed brick work

HIGHLIGHTS:• ½ brick walling and brick column – Cost effective as it is used in between columns.• Filler slab – Reduce the cost of RCC.• Exposed brick work – Save plastering costs.• Pre-fab panel roofing – saves on shuttering costs.• Hollow wall construction – provide thermal insulation.• Brick jallie – saves on cost of window.• Exposed brick parapet.

BRICK JALLIE

BRICK CORBELLING

BAMBOO HOUSEWHY BAMBOO?• Bamboo is a versatile construction material which is affordable, durable and very suitable for

earthquake prone regions. It is a light weight, long lasting and renewable building material.• In case of earthquakes, bamboo house won’t cause any death if it collapses and is easy to mend

and repair.• Bamboo is used as columns, roof trusses, scaffolding and ladders, acting as a good substitute for

wood.• Boards made up of bamboo mats are used in wall panelling, roof panelling , door and window

panelling, false ceiling, flooring, etc. • The use of these boards and other bamboo products makes the house construction not only cost

effective but also offers exotic designs.

MAIN FEATURES:• Eco-friendly structure.• Light in weight.• Wooden stilts and bamboo mat flooring.• Self sustaining bamboo plantations – livelihood initiative for rural areas.• Use of bamboo – columns, walling, roof framework and corrugated roofing material.• User friendly in earthquake prone areas of Northeast and Andaman & Nicobar Islands.• Exotic interior décor.• Water resistant walls with cement plastering.• Fire resistant with CuSO4 chemical treatment.

CONSTRUCTION PROCESS

FOUNDATION• The foundation is made with normal un-coursed rubble stone masonry.• Wooden / cement / brick stilts with wooden beams acting as plinth bands are also used.• The plinth has been constructed with brick masonry and plinth band is provided.• A pair of treated bamboos are assembled as columns and inserted at equal distance in the foundation.

CROSS SECTION OF FOUNDATION

FOUNDATION WORK IN PROCESS.

ROOF• The roof is a combination of trusses in twin bamboo culms, structurally connected with gusset plates in bamboo mat boards and nut bolted.• Purlins of twin bamboos are nut bolted to the truss and then bamboo mat corrugated sheets are secured on the purlins with the help of J-bolts.

DOORS AND WINDOWS• The doors and windows are integrated into the walling.• Frames are made in the composite of bamboo and teak wood.• Shutters are made in bamboo mat board.• It absorbs heat and keeps the interiors cool and greatly enhances the ambience of the house.

FLOORING• The flooring has been done with IPS (Indian Patent Stone) finished in brick red colour, with a green separating band at door

positions.• Alternatively, flooring can also be made with mud or terracotta tiles or stone tiles with finishing, which are cost effective.

HIGHLIGHTS:• Economical in the regions where bamboo is abundantly available locally.• Ideally suited for earthquake prone areas.• Highly energy efficient.• Bamboo mat corrugated sheet roofing is both heat resistant and waterproof, it doesn’t have any long term ill health effects.• The complete bamboo structure is fire retardant and anti-termite.

INSIDE VIEW OF THE ROOF TRUSS JOINTS.BAMBOO MAT CORRUGATED SHEET BEING LAID ON THE ROOF.

WINDOW PANES MADE UP OF BAMBOO MAT, PROVIDE AESTHETIC LOOK.

TRUSS JOINED WITH GUSSET PLATES.

A BAMBOO DOOR

MAKING A BAMBOO DOOR.

Climate control only influenced the design adopted-a central courtyard surrounded by construction of high walls with a balcony and small wind apertures to allow air circulation as well as preventing dust blow-ins during sandstormsHunnar shaala of Bhuj ,has replicated a cost effective housing typology based on using upgraded construction material, while retaining the design fundamentals .

STONE PATTI CONSTRUCTION

Main featuresStone patti flat and sloping roof-no steel and centering and shutteringReconstituted cement concrete blocks masonry used for wallingSpacious courtyard and roof water harvesting facilitySolar lighting facilityClimate control due to providing of thick walls

Dressed stone masonryTraditional method of construction in RajasthanNatural stones available locally are dressed manually and are laid to create wallsDue to the thickness of the walls it has certain advantages-Less energy consumptionThe thickness is more, so it gives more thermal comfort.The process is laboUr intensive and promotes local economy

Windows• Openings are smaller to protect the inside from the severe heat from outside• Small stone slabs are fixed as stone lintels instead of using of RCC.• No usage of steel or concrete for the lintels or for the slab.

Material required• Sand• Cement• Boulder stones• 6 to 12 mm aggregate• 15 to 20 mm aggregate• Water Tools• Spade• Pan• Trowel• Wooden planner• Sieve• Mould

Reconstituted cement blocks

• To save the usage of cement ,big size stones are inserted into the concrete in a rectangular mould.

• After remoulding ,the blocks are cured for two weeks and used for construction process.

Superstructure :

Roofing• The stone patti roofing is a traditional method for making the flat and sloping roofs.• It is cheaper than rcc roofing as in Rajasthan the stone slabs are available at a very low cost and can be used

directly without any centring or shuttering as is required for a normal RCC work• It is also a faster process as the stone slabs are simply to be lifted to the roof and placed on the beams

Rain water harvesting

Rain water harvesting system is done through the roof. A pvc pipe is connected with the roof outlet and is joined to the collection tank constructed under the flooring of the verandah.