EXECUTION OF BUILDINGS

MATERIALS

Water:

• Water should be clean, fresh and free from all chemicals, oils, salts and deleterious materials and vegetable growth.

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• Water has to meet requirements mentioned in Cl.5.4 of IS: 456-2000.

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Earth:

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• Soil used for filling shall be free from all garbage, organic and vegetable growth including roots, weeds etc.
• Expansive soils having high swelling index eg. Black cotton soils should not be used for basement filling.

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Sand (Fine Aggregate):

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• Sand to be used shall be composed of hard siliceous material and shall be clean, sharp, hard, strong and angular type.
• Sand shall be clean river or pit sand of approved quality and free from salts, earth, dust, or other impurities.

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Coarse Aggregate:

• The coarse aggregate shall be from hard granite crushed stone confirming to IS 383:1970.
• The pieces of aggregate shall be non porous, hard, strong, durable, clean and free from clay, rounded in shape and shall have granular or crystalline non powdery surfaces.
• The aggregate shall be well graded.

Cement:

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The following cements may be used with prior approval of the competent authority.

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• Ordinary Portland Cement 43 Grade IS:8112

• Ordinary Portland Cement 53 Grade IS:12269

• Portland Pozzolana Cement 53 Grade IS:1489

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• The quality of cement shall be in conformity to the performance characteristics given in IS:8112-1989.

• The cement should be delivered to the site in sound dry bags and shall be stored properly.

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• The cement shall be procured in standard packing (50 kg per bag) from the authorized manufactures.

• Cement shall be got tested for all the tests as directed by the Engineer-in-charge atleast once in a month in advance before the use of cement bags bought and kept at site godown.

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• Cement bags required for testing shall be supplied by the contractor at free of cost.

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• Cement should not be placed directly on cement mortar or cement concrete flooring . A wooden platform or false floor a sheet of water proof paper should be provided.

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• As a rule cement should not be stored longer than three months

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Bricks:

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• Bricks for masonry shall be common burnt clay

building bricks having a minimum crushing strength

of 40 kg/sq.cm and shall confirm to the relevant

specifications of IS:1077-1995.

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• They shall be sound, hard and thoroughly well burnt,

but not over burnt, with uniform size having rectangular faces with parallel sides and sharp straight right angled edges and be of uniform colour with fine compact uniform texture. Bricks shall be free from flaws, cracks and nodules of free lime.

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• Water absorption after 24 hours immersion in cold water shall be not more that 20% by weight. They shall not absorb more than 10% by weight after immersion for six hours.

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• They shall emit a clear metallic ringing sound when struck by a mallet and shall not break when dropped on their face, from a height of 60cm.

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STEEL

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• Mild Steel shall conform to IS:432-1982, High Yield

Steel Deformed bars shall conform to IS:1786-1985

and binding wire shall conform to IS:280.

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• The diameter and weights of steel should be as per

IS:1786-1985.

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6Ø - 0.22 kg/m 8Ø - 0.39 kg/m 10Ø - 0.62 kg/m

12Ø - 0.89 kg/m 16Ø - 1.58 kg/m 20Ø - 2.47 kg/m

25Ø - 3.85 kg/m 32Ø - 6.31 kg/m

WOOD

• The wood shall be well seasoned, uniformly colored and

shall be free from knots, cracks, shakes, splits, cross grains

etc.

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• The wood shall be durable and reasonably straight grains

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• Moisture content of wood used for frames of doors and

windows in coastal area shall be 16% to 18%.

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• Moisture content of wood used for frames of doors and

windows inland area shall be 14% to 15%.

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• Moisture content of wood used for shutters of doors and

windows in coastal area shall be 15% to 16%.

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• Moisture content of wood used for shutters of doors and

windows in inland area shall be 12% to 14%

Execution:

• Execution as per approved standard specifications.
• As per approved estimate.
• As per approved drawings.
• Approved materials.
• Any changes after approval of the competent authority only.

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WORK EXECUTION

Marking

• Clear Jungle, Garbage if any and Level the Surface

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• Study & Keep ready Architectural & Structural Drawings

while giving marking for the Structure.

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• Use Precise Tape for Marking.

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• Mark out Peripheral Center Line of the Structure on four

sides duly verifying both the diagonal measurements.

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• Mark out internal Center Lines and verify the all internal

diagonal measurements in both the ways.

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• Mark All Column Center Points.
• Provide Base Lines & Bench Marks on Four Sides (Pillars).

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• Maintain Bench Marks throughout the period of Construction

without causing any disturbance to them.

Earth Work Excavation for Foundations

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• Mark out the Dimensions of Footing / Pile Cap

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• Verify whether the Centre of all Foundations Coincide with

the Center of the Columns.

• All foundation works are to be carried out in dry and workable condition. Hence, dewatering arrangements are to be made if raised water table is observed in foundations.
• Shoring, Sheeting, Planking, Strutting etc. arrangements shall be made as per the directions of the Engineer-in-Charge.
• Excavated earth shall not deposit at the edges of foundations. Min. clearance to provide walk way to workers shall be maintained.

PILE FOUNDATION

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• Pile foundations are normally used in Expansive

Soils, Cohesive Soils with low bearing capacity.

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• Pile foundations with Under Reamed Piles

commonly used for normal buildings.

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• Piles shall be installed as accurately as possible

according design and drawings vertically.

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• Angular Deviations should not exceed 1.50%

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• Position Deviation should not exceed D/6 or 75mm

whichever is less

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• Minimum Length of Pile should be 3.50m

• Reamer (Bulb) Diameter Du shall be 2.50 time Diameter of Stem (d).

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• Up to 300 mm dia. Spacing Bulbs should not exceed 1.50 times Diameter of Bulb (1.50 Du).

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• For Piles Diameter greater than 300mm Spacing Bulbs should not exceed 1.25 time Diameter of Bulb.

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• The top most bulb should be at a distance of 1.75m from Natural Ground Level.

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• The Minimum Clearance between bottom of Pile Cap embedded in soil and bulb should be 1.50 times diameter of bulb.

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• Distance between two Under Reamed Piles should be less than 1.50 time Diameter of Bulb.

CONCRETING

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• No concrete shall be cast in the absence of the works in charge

engineer.

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• All the materials used should be of good quality and in accordance with

respective APSS and IS Codes.

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• All concrete works shall be built to the lines, grades and dimensions as

per the designs and drawings.

DESINGN MIX & NOMINAL MIX

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• Design Mix is preferred to Nominal Mix.

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• If the Design Mix Cannot be used for any reason on the work for Grades

of M20 or lower, Nominal Mix may be used with the permission of the

Engineer-in-Charge

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• Process of Mix Design takes a minimum period of 28 days. Hence, for

getting Mix Design concrete ingredients shall be furnished well in

advance.

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• Mix Design done earlier not prior to one year may be considered

adequate for later work provided there is no change in source and the

quality of materials.

• The design mix shall be got approved by the Engineer-in-Charge before proceeding with the concreting.

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• The mix shall be designed to produce the grade of concrete having required workability and Characteristic Strengths.

MIXING CONCRETE

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• For Design mix where site mixing is permitted

shall be with concrete mixtures with weigh batching scale.

• Materials shall be weighed and batched in mechanical weigh batchers as per specified proportions of the approved design mix.
• Materials requiring Volumetric mixing, wherever permitted should be measured separately in boxes of appropriate size before being mixed in the specified proportions.

• The concrete shall be mixed in machine mixer until the mixture is of uniform color & consistency and in no case , for less than two minutes.
• Mixer should not be loaded beyond its rated

capacity.

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WATER - CEMENT RATIO

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• Water is key ingredient of Concrete

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• Excess Water result in Weak Concrete

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• Less Water result in Unworkable Concrete

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• Quantity of Water used shall be as specified in Mix

Design.

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• To obtain required Workability Plasticizers shall be

used as per the Directions of the Engineer-in-Charge.

CONCRETE PLACING

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• Concrete shall be placed and compacted before

initial setting of concrete commences and should

not be subsequently disturbed.

• Concrete shall be deposited as nearly as

practicable directly in its final position.

• Shall not be re handled in a manner which will cause segregation and loss of materials,
• Shall not be dropped into place from a height exceeding 1 meter or handled in a manner which will cause segregation.
• Concrete shall be deposited in successive horizontal layers to a compacted thickness not more than 45 cm.

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• Shall be placed as rapidly as practicable to prevent formation of cold joints or planes of weakness between each succeeding layer within the pour.
• When concrete is conveyed by Chutes, the plant shall be of such size and design as to ensure practically continuous flow.
• Slope of the chute shall be so adjusted that the concrete flows with the use of any excessive quantity of water and without segregation of its ingredients.
• The delivery end of the chute shall be as close as possible to the point of deposit.

COMPACTION OF CONCRETE

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• All concrete shall be compacted to produce a dense homogeneous mass.
• Concrete after depositing should be compacted thoroughly by means of mechanical vibration
• Vibrations shall conform to IS Specifications.
• Vibrators of Surface (Plate Vibrators), Immersion Type (Needle Vibrators) shall be used.
• Concrete shall be thoroughly surged around the reinforcement, around embedded fixtures and into corner of form work.

• The Hardened concrete shall be free from voids and cavities.
• Over Vibration result in Segregation of Ingredients of Concrete.
• Under Vibration result in Voids and Cavities in Concrete.

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• Immersion vibrators shall be inserted at points not more than 45 cm apart.

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• Immersion vibrators shall be withdrawn slowly.

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• Blending and melding of the concrete between successive layers shall be ensured.

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• Vibrators shall not contact with Reinforcement and Shutters.

Finishing & Protection:

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• The finished surface shall be uniform in texture

and free from screed marks or other imperfections.

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• The concrete surface shall be consolidated, smooth

screeded and leveled to produce even surface.

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• The fresh concrete shall be protected from

defacements, damage due to construction

operations, rain, sun and winds and from foot

traffic until concrete has hardened.

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• The prepared surface shall be approved by the

Engineer-in-Charge.

CURING

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• Curing is the Maintenance of a satisfactory moisture content and

temperature for complete hydration in concrete for a period of time

immediately following placing and finishing so that desired properties may

develop.

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• Curing has a Strong Influence on the properties of the Concrete.

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• Proper Curing increase Strength, Durability, Water Tightness, Abrasion

Resistance, Volume Stability and Resistance to Freezing & Thawing.

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• All exposed faces of concrete shall be kept continuously moist for a

minimum period of 28 days by spraying water at regular intervals or by

covering with gunny bags which shall be constantly sprinkled with water.

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• For curing floors, flat roofs, concrete pavements and other level surfaces

the ponding method of curing shall be adopted

CENTERING

• Form work design, details and tolerances shall be confirmed

to IS:14687 and IS 456:2000.

• Only Steel form centering shall be used.
• Steel Forms with Surface Dents, Bulges, Undulations or

Holes shall not be used

• Form work shall be substantially and rigidly constructed of

steel and shall be true to dimensions.

• Form work shall be constructed to confine and shape the

concrete to the required shape, lines and dimensions

described.

• Shuttering shall be erected true to line and securely braced,

cross braced, strutted and supported with props at close

intervals to prevent deformation under the weight of

pressured wet concrete and constructional loads, wind

pressure and other forces.

• The face of form work in contact with concrete shall be

cleaned and treated with Release Agent.

• All Shuttering joints shall be sufficiently tight to prevent

leakage of cement slurry.

• All faulty joints of centering shall be adequately caulked (filling & sealing joints)
• Shuttering joints shall be closed with
• Standard Shuttering Oil, Engine Oil or Filtered Waste Oil free from Carbon particles and impurities shall be used as Release Agent.
• Release agents should be applied so as to provide a thin uniform coating to the Forms without coating the reinforcement.
• Stripping Time of Form Work as Per IS 456:2000
• Columns & Beams Vertical Forms 16 to 24 h
• Soffit Form Work to Beams: 7 days
• Props to Beams (up to 6.00m span) 14 days
• Props to Beam (above 6.00m span) 21 days
• Props to Slabs (up to 4.50m span) 7 days
• Props to Slab (above 4.50m span) 14 days.

REINFORCEMENT FOR RCC WORKS

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• Reinforcement shall be of High Yield Strength Deformed (HYSD) bars of grade Fe 415 / Fe 500 confirming to IS 1786-1985.

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• Reinforcement shall be steel and shall be free from corrosion, oil grease, paint and dirt at the time of fixing in position and subsequent concreting.

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• Reinforcing steel bars shall conform accurately to the sizes, dimensions and shapes given as per designs and drawings.

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• Bars shall be bent cold to the specified shape and dimensions and the bars shall be hooked or bent accurately and placed in exact position as per designs and drawings.

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• Bars of full length shall be used. Reinforcement shall be lap jointed or spliced only in unavoidable. The overlaps shall be staggered for different bars and located at points along the span where neither shear or bending moment is maximum.

• Not more than 33% of the bars as specified in drawing shall be lapped at one section.
• The Reinforcement shall be securely held in position and bound together tight by annealed binding wire and b y using stays, blocks or metal chairs, spacers, hangers or other approved devices at sufficiently close intervals.
• Reinforcement shall not be allowed to sag between supports. Layers of bars shall be separated by spacer bars or other approved devices.
• Stirrups, Ties, Links should be securely wired to the main reinforcement.
• It shall be ensured that the bars are not displaced during concreting or any other operation over the work.
• All bars protruding from concrete and to which other bars are to be spliced and which are likely to be exposed for an indefinite period shall be protected by thick coat of neat cement grout to prevent from corrosions.

• Reinforcement chairs shall be used to separate bottom steel from the top steel and to maintain corrective effective depth.

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• Reinforcement chairs shall be slightly lesser size so as to accommodate the chair underneath the top steel and after allowing the required covers to the top and bottom steel.

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• The chair shall be minimum of 450mm long and should have legs bent in opposite directions to ensure stability.

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• The chairs shall be placed on cover block so that the legs do not stick out once the shuttering is removed.

COVER BLOCKS

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• Before concreting, cover blocks shall be fixed in all RCC works to separate the reinforcement from the shuttering so that when the concrete is set the reinforcement is well within the concrete section at a distance from the outer face with specified cover to reinforcement.
• Cover blocks shall be reasonably good for using appropriate grade of RCC work.
• The mortar for preparing cover blocks shall be at least be of proportion 1:2.
• Cover blocks shall be prepared on clean and level platform by separating the mortar in moulds of required size and depth.
• When the mortar is still green strands of tying wire shall be inserted into each block. This wire is useful for tying the block to the reinforcement.

• After 24 hours the cover blocks shall be removed from the mould and cured for about seven days.

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• A properly made cover block does not get crushed when the reinforcement is tied over it and during the concreting work.

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• Clear Cover to Slab Reinforcement: 15mm
• Clear Cover to Beam Reinforcement: 25mm
• Clear Cover to Column Reinforcement: 40mm
• Clear Cover to Footing Reinforcement: 50mm

RCC SLABS

• The RCC Slab laid should leak proof.

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• After centering is removed and curing period is

over the slabs shall be put to test by stagnating � water of 15 cm depth for one week and watched

carefully to test the leakages in any.

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• If there are any leakages, the contractor shall

immediately rectify the same at his own cost and

again test the same to see that there are no

leakages.

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• No payments will be made to the contractor on

this account either for testing or for rectification

thus carried out.

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• The officer observing the leakage test shall issue

a certificate to this effect before final bill is made.

• After observing for two rainy seasons as defect liability period if the roof or floor is found to be perfectly leak proof and no moisture or dampness is seen underneath at ceiling the slab, the contractor can ask for refund of Deposits from the department.

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• The variation thickness of RCC Roof slab due to varying spans or special covering materials should not affect the general roof surface which should be uniform.
• For all slabs to be laid to be laid MS hooks to be provided as directed by the department for fixing fans and lights etc.
• PVC pipes have to provided as directed by the department in slab at the specified places for running electrical wiring.

BASEMENT FILLING

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• Basement shall be filled with suitable materials. Cohesion less materials such as sand or stone dust are suitable materials for basement filling.

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• Basement filling shall be done in layers not more than 15cm thickness.

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• Consolidation shall be done by watering and ramming until maximum density is achieved.

BRICK WORKS

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• All bricks to be used in the work shall thoroughly soaked in water before use to prevent absorption of water from the mortar.

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• The bricks shall be set in cement mortar (1:6) proportion for basement and (1:8) proportion for super structure by adopting a proper bond (preferably either English Bond or Flemish Bond) throughout the wall.

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• The walls shall be taken up truly plumb. All courses shall be truly horizontal (level) and truly vertical.

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• Vertical Joints of consecutive courses shall not come directly over one another.

• Vertical Joints in alternate course shall come direct over one another.
• Joints shall be fully filled with mortar and racked. Each brick shall be laid with full joints of cement mortar on it’s bed, ends and sides in one operation.
• No feeding of mortar by using excess water shall be allowed.
• Half Brick masonry shall be constructed only in stretcher bond
• Reinforcement for half brick walls shall be in the form of MS bars and shall be of specified quantities.
• Reinforcement for half brick walls shall be well embedded in cement mortar at every third course and half the joint thickness of mortar shall first be laid and the other half laid after the reinforcement is placed.

• The free ends of the reinforcement wherever possible shall be pegged in the mortar joints of main brick walls.

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• Where the supports are not monolithic with beam or slab the bearing surface shall be plastered with Cement Mortar (1:3) with a craft paper laid over the plaster before laying the concrete.

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• The Vertical face of the masonry rebate at bearings shall be plastered smooth with CM(1:3).

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• For beams the craft paper shall be continued to the sides, folding the paper neatly to the plastered vertical face of the masonry opening.

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• Lintel slabs shall allow resting on PCC Bed Blocks on either side of opening.

PLASTERING

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• The surface shall be prepared by roughening of the back ground and racking joints.

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• The surface of the wall shall be kept wet for 2 hours before plastering

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• Guides (patches of 15cmx15cm) of required thickness at not more than 2.00 meters intervals horizontally and vertically shall be applied over the entire surface truly in the plane and truly plumb to serve as guides.

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• Plaster shall be started from the top and worked down towards plinth.

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• The work shall be tested frequently with a plumb bob and straight edge.

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• Mortar shall be dashed and pressed over the surface and then brought to smooth and uniform surface by means of float and trowel.

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• The plaster shall be well pressed into the joints.

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• All corners, junctions and arises shall be brought truly to a line and plumb.

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• The finished surface shall be watered for a period of at least 10 days.

WATER PROOF PLASTER OVER ROOF

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• On the clean wet surface of the concrete slab,

before it has set, a layer of cement plaster shall be

laid to give an average depth of 20mm over the

concrete.

• The mortar to be used shall be of CM(1:3)

proportion mixed thoroughly with a standard water

proofing material with water repelling properties to

ensure non absorption.

• Gauges should be put on the floor about 3.00 metes

apart to ensure even thickness.

• Plastering must be done in squares and thread

lining at interval 45cm x 45cm shall be done to

avoid cracks.

• After completing plastering it shall be covered with

two inches of grass or saw dust and kept wet for

three weeks.