Specification and Estimation Lecture-5

8/13/2019 Specification and Estimation Lecture-5

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Specification and Estimation

Lecture: 5

Basic information necessary to write specification for differentItems ofWork (Making of a Building)

Items of Work Materials Proportioning Workmanship Testing

Earthwork in

excavation of

Foundation Trenches

Clear site of grass, roots of trees and other organic matter

Dimensions of the excavation as shown in drawings or as decided by

Engineer in charge

Side of the trenches vertical and bottom level both longitudinally and

transversely

Bottom of trenches to be sprinkled with water and rammed

Excess digging to be filled with concreteAll excavated material to be kept at least 1 m away from the trenches

All existing pipes, cables, sewers etc. to be temporarily shored

All valuables and materials found during exaction to be the property of the

Government

The cost of all materials and labour required for fencing in and protection

against risk of accidents are born by the contractor

Earthwork In Filling Earth used for filling to be

loose, free from brick bats,

stone and boulders not larger

than 75 mm in any direction,

salts, organic or other foreign

matter

The filling to be done in layers not exceeding 20 cm each layer.

Each layer to be watered, rammed before the next layer is laid

Earth to be rammed with iron hammers where feasible or crowbars

In case of filling under floors, the finished level of filling to be in slope as

intended in the laying of the floor

Sand Filling in Plinth Sand used in filling to be fine,

free from dust, organic and

foreign material

Sand to be spread in layers not exceeding 20 cm and to be saturated with

water

Ramming will be through a number of hammers where the distance between

two hammers not to exceed 1.5 m.

Successive course of ramming to be in transverse direction

Before ramming the final layer, the entire filled up area is flooded with water

Final filled surface to be leveled in both directions to the desired slope.


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Brick Soling in

Foundation Trenches

Picked Jhama or 2nd

class bricks

in dry condition to be used

Bricks are used as headers with frog upwards

Bricks to be laid breaking joints and small gap between them to be filled with

local fine sand or dry loose earth

Brick bats used to break joints to be placed at the edges of trenches

The finished surface to be leveled in both directions(longitudinally as well as transversely)

Lime concrete in

trenches

Coarse aggregate from breaking

good quality over-burnt or well

burnt dense brick bats small

enough to pass through 32 mm

dia ring

Fine aggregate to be surkhi or

cinder(preferably surkhi) made

from well burnt first class

bricks bats grounded small

enough to pass through I.Ssieve of 4.75 mm

Lime to be freshly burnt, slaked

and free from ashes and

screened through a sieve of 3

meshes to a cm. The slaking of

lime is done at site unless

otherwise specified

Coarse

aggregate,

surkhi and lime

proportion to

be 100:36:18

The mixing to be done by hand or mechanical mixer.

Hand mixing to be done on clean solid water-tight masonry platform

Brick ballast to be soaked in clear water for at least 2 hours before mixing and

stacked evenly on a platform in maximum height of 30 cm

Lime and surkhi to be measured with wooden boxes measuring generally 35

cm x 25 cm x 40 cm and mixed dry till of uniform colour and spread over

stacked ballast

The whole mixture to be turned over once without adding water and further

three times gradually adding water so that the whole surface of the ballast

becomes coated with mortar and the mix becomes plastic enough to giveuniform concrete

The volume of concrete to be limited to what has to be used in 1 day

Old and stale concrete not to be used

Concrete to be laid (not thrown) in courses not more than 20 cm thick at a

time and consolidated until the layer is 15 cm thick

Weight of the compacting hammer not to be less than 4.5 kg and area not

more than 300 sq cm.

Consolidation to be completed only till a skin of pure mortar covers the

surface

In hot season lime water to be sprinkled regularly during ramming to keep the

concrete wet

No ramming to be done on the next day when the mortar has started settingGreen work to be protected from rain by suitable covering

Where joints in layer are unavoidable, the end of each layer to be sloped off

to an angle of 30 degrees

Concrete to be kept moist with gunny bags, sand for at least 7 days and no

masonry to be laid on the lime concrete bed within this period

Two days

after

ramming, the

concrete to

be tested by

digging a

hole about

7.5 cm deep

and 7.5 cm in

dia. Andfilled with

water

In this test,

the water

level does

not go down

The safe

compressive

strength of

lime concrete

is taken as 43

tonnes / sqm.

Cement Concrete Coarse aggregate is crushed or

broken from hard stone

Cement

1

Mixing:

Hand Mixing: Hand mixing is permitted only for small works but normally


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obtained from hard stone. It is

hard, strong, dense and durable,

clean and free from soft friable,

thin, flat, elongated or

laminated, flaky pieces and isroughly cubical in shape. It is

free from dust and any other

foreign matter. It can be gravel

or river bed shingles or pit

gravel. The size of the coarseaggregate is 20 mm graded

down and retained in 5 mm

square mesh so that the voids

do not exceed 42 %. For road or

mass concrete work, bigger size

of 40 to 60 mm is prescribed.

Fine aggregate is usually

coarse sand able to pass

through IS sieve of 4.75 mm.

Sea sand is not used. Sand is

free from dirt and organic

matter. Crushed dust stone may

also be used as fine aggregate.

Cement is fresh Portland

cement conforming to IS: 269.

Quantity of water:The quantity

of water to be used for each mixof 50 Kg cement to give the

required consistency is not

more than 34 litres for 1:3:6

mix, 30 litres for 1:2:4 mix, 27

litres for 1: 11/2 : 3 mix and 25

litres for 1:1:2 mix.

In the case of vibrated concrete,

the limit specified may be

Fine aggregate

2

Coarse

aggregate 4

i.e. 1:2:4

Measured by

measuring

boxes 30 cm x

30 cm x 38 cm

The above is

equivalent to 1

bag of cement

of 1/30 cum or

.035 cum.

Cement ismeasured by

bag weighing

50 kg when

dry.

While

measuring

aggregate,

shaking,

ramming or

hammering is

not permitted.

all structural concrete is mixed in a mixer machine.

The mixing is done on a clean watertight masonry or concrete slab or steel

plate platform.

Measured quantity of sand is spread evenly after which the cement is dumped

on the sand and distributed evenly.The cement and sand are then mixed thoroughly with spade turning the mixer

again and again until it is of even colour throughout and is free from streaks.

The measured quantity of coarse aggregate is then spread out and the sand

cement mixture is spread on its top or a reverse operation is done.

The complete mixer is then turned at least three times by shoveling and

turning over by twist from center to side and then back to the centre and

again to the sides.

A hollow is made in the centre of the pile of the mixed pile and three quarters

of the water required is added while the mixture is turned towards the centre

with spades.

The remaining water is added by a water can fitted with rose head, slowly

turning the over and over again until a uniform texture and consistency isobtained.

The mixing platform is washed at the end of the day.

Machine mixing: The mixer drum is flushed clean with water. Measured

quantity of dry coarse aggregate is placed first in the hopper.

This are followed with measured quantity of fine aggregate and then cement.

In case, damp sand is used, add half of the quantity of coarse aggregate.

The dry materials are mixed in the mixing drum for at least four turns of the

drum, after which the correct quantity of water is added gradually while the

drum is in motion, to ensure even distribution with the dry materials.

The total quantity of water for mixing is introduced before 25 percent of the

mixing time has elapsed and is regulated to achieve the specific water cement

ratio.

The mixing is thorough to have a plastic mix of uniform colour.

The complete contents of the mixed concrete are emptied before recharging.


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suitably reduced to avoid

segregation.

The quantity of water is

regulated by carrying out

regular slump tests.

When the mixer is closed down for the day or for any time exceeding 20

minutes, the drum is flushed clean.

Mi xing time: The materials are mixed in a drum for a period of not less than2 minutes and until a uniform colour and consistency are obtained. The time

is counted from the moment all the materials have been put into the drum.

Laying: The entire concrete used in the work is laid gently (not thrown) in

layers not exceeding 15 cm and is thoroughly vibrated by means ofmechanical vibrators till a dense concrete is obtained.

The Engineer-in-Charge may however relax this condition at his discretion

for certain items depending upon the thickness of the members and feasibility

of vibrating the same and permit hand compaction.

Hand compaction is done with the help of punning rods and tamping withwooden tampers so that concrete is thoroughly compacted and completely

worked into the corners of the formwork.

The layers of concrete are so placed so that the bottom layer does not finally

set before the top layer is placed.

Compaction is completed before the initial setting starts i.e. within 30 minutes

of addition of water to the dry mixture.

During cold weather casting of concrete is not done when the temperature

falls below 4.50C. During hot weather precautions are taken to see that the

temperature of wet concrete does not exceed 380C. Concrete is not allowed tobe deposited under water.

Where found necessary to deposit any concrete under water, the method and

equipment is first approved by the Engineer-in-Charge.

Concrete is deposited continuously until it is brought to required height;

while depositing, the top surface is kept as nearly level as possible and the

formation of seams are avoided.


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The concrete is deposited under water by one of the approved methods such

as Treamic Method. Drop and bottom bucket, bags etc.

When the placing of concrete is suspended, or resumed on the following day,necessary roughening of the surface for joining future work is done before the

concrete sets. When the work is resumed the previous work must be

thoroughly cleaned, roughened, watered and a grout of neat cement slurry of

the proportion, I kg of cement per 2 litres of water applied uniformly.

Protection and curing: Freshly laid concrete is protected from rain by

suitable covering. The work should also be protected from damage and rain

during construction. After the concrete has begun to harden i.e. about 1 to 2

hours after its laying, it is protected with moist gunny hags, sand or any other

material approved by the Engineer-in-Charge against quick drying.

After 24 hours of laying of concrete the surface is cured by flooding withwater of about 25 mm depth or by covering with wet absorbent materials.

The curing is done for a minimum period of 14 days.

Over the foundation concrete, the masonry work may be started after 48 hours

of its laying, but the curing of cement concrete is continued along with the

masonry work for a minimum period of 14 days. In case of cement concrete

used as sub-grade for flooring, the flooring may be commenced before the

curing period of sub-grade is over but the curing of sub-grade is continued

along with the top layer of flooring for a minimum period of 14 days. The

water used for curing shall not produce any objectionably stains or unsightly

deposit on concrete surface.

Form work: If centering and shuttering are required to be done for this work

this are done in accordance with the specifications for form work under

Reinforced cement concrete.


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Reinforced cement

concrete (R.C.C.)

Same as cement concrete

except the size of coarse

aggregate is 20 mm unless

specially mentioned in the type

of work.Form work includes all forms

or moulds required for forming

the concrete which is cast-in-

situ, together with all

temporary construction

required for their support.

Form work is of plywood, or

steel approved by the Engineer-

in-Charge. Timber used for

form work should be easily

workable with nails withoutsplitting and of light weight. It

is stiff and strong enough to

avoid undue deflection when

loaded and not liable to warp

when exposed to sun and rain or

wetted during casting of

concrete.

Form work is of rigid

construction true to shape and

dimensions shown on drawings.

It is st rong enough to withstandthe dead and live loads and

forces caused by ramming and

vibrations of concrete and other

incidental loads imposed upon

it during and after casting of

concrete. It is made sufficiently

rigid by using adequate number

of braces and ties. To make up

Same as

cement

concrete.

Propping and Centerin g: Props used for centering are of steel, timber, posts,

ballies or any other material approved by the Engineer-in-Charge. In case

when ballies are used none is less than 100 mm in diameter measured at mid

length and 80 mm at thin end. Ballies rest on wooden sole plates of not less

than 40 mm thickness having a minimum bearing area of 0.1 square metre laidon ground or on 40 X 40 mm thick brick masonry pillars in mud mortar of

height not exceeding 40 cm. All props are further provided with double

wedges between the sole plates and the props so as to facilitate tightening and

easing of shuttering without causing shock to the concrete.

In case a span exceeds 4.50 metres and height exceeds 3.50 metres , suitable

horizontal as well as diagonal bracings are provided after accounting for all

forces including action of the wind which may produce lateral forces. In

case, the height of centering exceeds 3.50 metres, the props may be provided

in multi-stages. The detail of splicing the props at each stage is as per

approved drawing.

Before the casting of concrete is started, the props and wedges are thoroughly

checked to see that these are intact. While the casting of concrete is in

progress, at least one carpenter is to keep a constant watch on the props and

take immediate remedial measures, as soon as any of them gets loosened.

Shuttering: The shuttering is of approved dressed timber of well seasoned

wooden boards to give a smooth and even surface and the joints do not permit

leakage of cement grout. The timber is free from loose knots, projected nails,

splits, adhering grout or other defects that may mar the cement surface of

concrete. It is not be so green or wet as to shrink after erection. Species of

timber which are not affected appreciably by its contact with water are used.

When metal forms are used, all bolts and nuts are countersunk and wellground to provide a smooth plain surface. Opening for fan clamps and other

fittings connected with services are provided in the shuttering as directed by

the Engineer-in-Charge.

Surface treatment f or shuttering: The surfaces of timber shuttering that

would come in contact with concrete are thoroughly cleaned and well wetted

and coated with soap solution, raw linseed oil, or form oil of approved

manufacture, or any other approved material such as polythene sheets, to

Regular

mandatory

tests on the

consistency

andworkability

of the fresh

concrete are

done to

achieve thespecified

compressive

strength of

concrete.

Work tests

and slump

tests arecarried out as

per standing

practice.

Three test

specimens

are made

from each

sample for

testing at 28

days.


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any settlement in the form work

either before of during the

placing of concrete, hard wood

wedges are provided where

required.

All form work is so constructed

as to be removable in sections

in the desired sequence, without

damaging the surface ofconcrete or disturbing other

sections. Forms should be easy

to strip after connecting and no

piece should be keyed into the

concrete. The completed form

work is approved after

inspection by the Engineer-in-Charge before the

reinforcement bars are placed in

position.

prevent adhesion of concrete to form work.

The Engineer-in-Charge inspects and accepts the form work as to its strength,

alignment and general fitness before placing any concrete in the forms. But

such inspection is not to relieve the contractor of his responsibility for safetyof man, machinery, materials and for results obtained.

Camber: Suitable camber is provided in horizontal members of structures

especially in long members to counteract the effects of deflection. The

camber for beams and slabs are 4 mm per metre i.e. 1 in 250 and forcantilevers, at free end is

1/50

thof the projected length or as directed by the

Engineer-in-Charge.

Removal of Form Work: The form work is removed avoiding shock or

vibration that may cause any damage to concrete. In a slab and beam

construction, sides of the beam are stripped first; then the undersides of slab

and lastly the undersides of the beam. The period that elapses after the

concrete has been laid before undertaking the work of easing and removal ofcentering and shuttering is as given below according to IS 456-1978.

Parts of structure

1- Walls, columns and

vertical faces

of all structural

members

2- Slabs (props leftunder)

3- Beams soffits(props left under)

4- Removal of propsunder slabs

Where ordinary Portland cement is

used forms may be removed after

expiry of the following periods:

24 to 48 hours as may be decided by the

Engineer-in-Charge.

3 days

7 days

7 days


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.

(a) Spanning up to4.5m

(b) Spanning over 4.5m

5- Removal of propsunder beams and

arches:

(a) Spanning up to 6 m(b) Spanning over 6 m

7 days

14 days

14 days21 days

Reinforcement: Mild steel barsshall conform to the I.S.

specification, free from loose

rust, dust, loose mill scales,

coats of paints, oil or other

coatings which may destroy or

reduce bond. It is stored in

such a way so as to avoid

distortion and to prevent

corrosion.

In case of cantilever slabs and beams, the centering will remain till structures

for bearing down have been erected and have sufficient strength.

Bending of Overl apping: Bars are bent cold, correctly and accurately to thesize and shape as shown on the detailed drawing or as directed by the

Engineer-in-Charge. Preferably bars of full length are used. Overlapping of

bars, where necessary, is done as directed by the Engineer-in-Charge. The

overlaps are staggered for different bars and located at points, along the span,

where, neither shear nor bending moment is maximum. Overlapping of bars

can be kept apart by 25 mm or 11/4 times the maximum size of coarse

aggregate, whichever is greater, with concrete between them. But where this

cannot be done, the overlapping bars are bound together at intervals not

exceeding twice the diameter of such bars, with two strands of annealed steel

wire of 0.90 mm to 1.6 mm thickness twisted tight. In case of mild steel the

ends of rods are bent in to semi-circular hooks, having clear diameter equal to

four times the diameter of bar, with a length beyond the bend equal to fourtimes the diameter of the bar. In case of mild steel the ends of rods are bent in

to semi-circular hooks, having clear diameter equal to four times the diameter

of bar, with a length beyond the bend equal to four times the diameter of the

bar. In case of deformed bars the hooks are not required. Welding of bars are

permitted in lieu of overlap if approved by the Engineer-in-Charge.

Placing in Positi on: Reinforcement bars are placed in position as shown in

the drawings. Bars at their points of intersection are securely tied together


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with two strands of annealed steel wire 0.90 to 1.6 mm thick twisted tight to

make the skeleton of the steel work rigid so that the reinforcement does not

get displaced during the deposition of concrete. Tack welding is permitted in

lieu of binding with steel wire if approved by the Engineerin-Charge.

The bars are kept in position by the following methods as the case may be:

(1) For beam and slab construction, pre-cast cover blocks in cement mortar

1:2 about 4 X 4 cm section and of thickness equal to the specified cover are

placed between the bars and shuttering, to avoid sagging and to maintainrequisite cover of concrete.

(2) For cantilevered and double reinforced beams or slabs the vertical

distance between the horizontal bars are maintained by introducing chain

spacers or support bars of steel at 1.0 metre or at shorter spacing to avoid

sagging.

(3) For columns and walls the vertical bars are kept in position by means of

timber templates with slots accurately cut in them; or with block of cement

mortar (1:2) suitably tied to the reinforcement.

Mixing: Concrete is mixed by mechanical mixer except for small quantity

when Engineer-in-Charge permits otherwise. Same as Cement Concrete.

Consistency or Workabil ity: The concrete, which will flow sluggishly into the

forms and around the reinforcement without any segregation of coarse

aggregate from the mortar, is used. The consistency will depend on whether

the concrete is vibrated or hand tamped. It is determined by slump tests as

per I.S. recommendation.

Placing of concrete: Pouring into moulds. Placing of concrete is

commenced only after the Engineer-in-Charge has inspected the centering,

shuttering and reinforcements as placed and approved the same. Shuttering is

clean and free from all saw dust, pieces of wood or other foreign materials

and is treated as prescribed in surface treatment for shuttering.

In case of casting of concrete of slabs and beams, wooden planks or cat-walks


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supported directly on the centering by means of wooden blocks are provided

to convey the concrete to the place of deposition without disturbing the

reinforcement. Labourers are not allowed to walk over the reinforcement.

In deep trenches and footings, concrete is placed through chutes as directed bythe Engineer-in-Charge. In case of columns and walls, the shuttering is so

adjusted that the vertical drop of concrete is not more than 1.5 metes at a time.

During cold weather, with below 4.5oC temperature, laying of concrete is not

done. During hot weather, precaution is taken to see that the temperature of

wet concrete does not exceed 38oC. Unless permitted by the Engineer-in-

Charge no concrete is laid within half an hour of the closing time of the day.

The time between mixing and placing of concrete is not to exceed the initial

setting time of cement of 30 minutes.

Compaction: Concrete is compacted into a dense mass immediately after

placing by means of mechanical vibrators designed for continuous operations

during the whole period occupied for placing of concrete. The vibrators areso adjusted that the centers of vibrations approximates to the centre of the

mass being compacted at the time of placing. For certain items, such as roof

slab, depending on the thickness of the members and feasibility of vibrating

the same, the Engineer-in-Charge may permit hand compaction. Hand

compaction is done with the help of 16 mm diameter steel tamping rod and

tamping with wooden tampers so that the concrete is thoroughly compacted

and completely worked around the reinforcement and into corners of the form

work. The layers of concrete are so placed that the bottom layer does not

finally set before the top layer is placed.

Compaction is continued until the mortar fills the spaces between the coarse

aggregate and begins to cream up to form an even surface. Needle Vibratorsare withdrawn slowly so as to prevent formation of loose pockets in the case

of internal vibrators. The specific instructions of the makers of the particular

type of vibrator used are strictly complied with. Shaking of reinforcement for

the purpose of compaction is avoided. Compaction is completed before the

initial setting starts. Over-vibration or vibration of very wet mixes are

harmful and is avoided; under vibration is also harmful.

Construction Joi nts: The positions where construction joints are to be made


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will be as shown in structural drawing or as directed by the Engineer-in-

Charge. Such joints are kept to the minimum and are located where the shear

force is minimum and these are straight and at right angles to the direction of

main reinforcement.

When stopping the concrete on a vertical plane in slabs and beams, an

approved, stop-board is placed with necessary slots reinforcement bars or any

other obstruction to pass the bars freely without bending. The construction

joints on a vertical plane are keyed. Inclined or feather joints are not

permitted. Any concrete flowing through the joints of stop-board is removedsoon after the initial set. When concrete is stopped on a horizontal plane, the

surface is roughened and cleaned after the initial set. In case of columns, the

joints are horizontal and 10 to 15 cm below the bottom of beam running into

the column head. Concreting is carried out continuously up to construction

joints.

When the work has to be resumed, the joint are thoroughly cleaned with wirebrush and loose particles removed. A coat of neat cement slurry at the rate of

2.75kg of cement per square metre is then applied on the roughened surface

before fresh concrete is laid.

Curing: same as cement concrete.

Finishing:In case of roof slabs the top surface is finished even and smooth

with wooden trowel, before the concrete begins to set.

Immediately on removal of forms, the R.C.C. work is examined by the

Engineer-in-Charge, before any defects are made good. The work that has

sagged or contains honeycombing to an extent detrimental to structural safetyor architectural concept is rejected. Surface defects of a minor nature may be

accepted but should be made good as per direction of the Engineer-in-

Charge. The R.C.C. work is done carefully so that the thickness of plaster

required for finishing the surface is not more than 6 mm.


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Masonry work in

Superstructure

1st Class

Brickwork

Bricks are first class of standard

specification, regular in shape

and size with sharp edges andcorners. They shall emit a clear

ringing sound on being struck.

They is of uniform deep red or

copper colour, free from cracks,

chips, efflorescence, flaws andlumps of any kind. Dry bricks

shall not absorb more than 20%

of their weight when immersed

in water for 24 hours. Brick

shall have an average

compressive strength of not less

than 100kg per sq cm and notmore than 125 kg per sq cm.

For cement mortar, cement is

fresh Portland cement of

standard quality. Sand is

medium coarse sand, clean,

sharp and free from clay, mica

or organic matter. For lime

mortar, lime is slaked and fresh

stone-lime screened at work site

conforming to standard

specification. Surki is madefrom first class brick having

uniform colour and free from

admixture of foreign matter.

Water used is clean and

reasonably free from oils, acids,

alkalies, salts and vegetable

growth. Generally potable

Soaking of Br icks: all bricks are thoroughly soaked in water by submerging

them in clean water for at least four hours just before use. The wetted bricks

are stacked on a clean platform to avoid any contact with mud.

Laying: The bricklaying is of English bond unless specially mentioned. A

layer of mortar is spread on full width over a suitable length of the lower

course. Each brick is properly bedded with frog upward and set home (in

position) by gently tapping with handle of trowel or wooden mallet. Its inside

faces are buttered with mortar before the next brick is laid and pressed

against it. On completion of a course, all vertical joints are fully filled from

the top with mortar. Half, or cut bricks is not used except where necessary to

complete the bond. No damaged or broken bricks are used. Closers in such

cases, is cut to the required size and used near the ends of the walls. In

exposed brickwork, selected bricks of the specified class are used for face

work. The brickwork is true to line, plumb and all vertical joints are trulyvertical. Vertical joints in alternate courses shall come directly one over the

other. Thickness of brick course is kept uniform. All connected brickwork is

carried up simultaneously and no portion of work is left more than one metre

below the rest of the work. Where this are not possible, in the opinion of the

Engineer-in=Charge, the work is raked back according to bond (and not

toothed) at an angle not steeper than 45o. The work done per day should not

be more than one metre height. All iron fixtures, pipes, outlets of water, hold

fasts of doors and windows, which are required to be built into walls are

embedded in mortar or cement concrete as specified in their correct position

as per direction, as the work proceeds.

Joints: Brick is so laid that all joints are full of mortar. The thickness ofjoints shall not exceed 1.0 cm. All face joints are raked to a minimum depth

of 15 mm by raking tool during the progress of work when the mortar is still

green so as to provide proper key for plastering or pointing to be done. The

face of brickwork is cleaned on the same day on which brickwork is laid and

all mortar droppings removed promptly.

Brick Coping: The top courses of all plinth, parapet, steps and top wall below

R.C.C. is laid with brick on edges unless specified otherwise.


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Reinforced

Brickwork

water is used.

Mortar: The brickwork is done

with the specified mortar

(cement or lime) mixing theingredients in the specified

proportion. In the case of

cement mortar the unit of

measurement for cement is a

bag of cement and this are takenas 0.035 cu m. Sand in

specified proportion is

measured in boxes of suitable

size 35 cm X 25 40 cm. Sand is

measured on the basis of its dry

volume. In case of damp sand,

its quantity is increased suitablyto allow for bulkage. Materials

of mortar is first mixed dry till

of uniform colour on a solid

clean watertight platform and

then mixed wet at least three

times by adding water gradually

and evenly to have a workable

consistency of a stiff paste.

Only the quantity of cement

mortar which can be used

within 30 minutes are prepared

at a time. In case of limemortar, it is used on the day it is

made.

All bricks are of first class

quality and free from soluble

salt.

The mortar will consist of 1

part of fresh Portland cement

Curing: Brickwork is protected from rain by suitable covering when the

mortar is green. Masonry work in cement mortar or lime mortar is dept

constantly moist on all faces for a minimum period of seven days. Brickwork

carried out during the day is suitably marked indicating the date on which thework is done so as to deep a watch on the curing period.

Scaffolding: For all exposed brickwork, double scaffolding having two sets of

vertical supports are provided. The supports are sound and strong, tied

together with horizontal pieces over which scaffolding planks are fixed. Forall other brickwork in buildings, single scaffolding is permitted. In such

cases, the inner end of the horizontal scaffolding pole shall rest in a hole

provided only in the header course for the purpose. Only one header for each

pole is left out. Such holes for scaffolding shall, however, not be allowed in

pillars or columns less than one metre in width. The holes left in masonry

works for scaffolding purposes are filled and make good before plastering.

Laying of bricks: All bricks are thoroughly saturated by submerging them in

clear water for at least four hours before use. A line of bricks are first laid

with frogs downward in each direction to act as guide and to ensure that

cutting of brick is avoided. In case, a part brick has to be introduced this are

done at about the middle of the length. The gap between two lines of bricks


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Random

Rubble Stone

Masonry:

and 3 parts of coarse sand

passing through I.S sieve No.

480 and retain on No. 15 sieve

(i.e. between 4.75 mm to 5.5

mm).

Mild steel bars are straight and

free from rust, paint, grease etc.

All material as stated above

including water is of standard

specifications.

Shuttering will be of approved

dressed timber like seasoned

soft wooden boards of not less

than 3 cm thick. Faces incontact with concrete is free

from adhering grout, projection

nails, splits or such other

defects. Any timber that shows

any tendency to warp, shrink or

twist is adjusted. All shuttering

and framing is rigid, well

braced and sufficiently strong to

stand the pressure of wet bricks.

All props of approved size is

supported on double wedges.

Stone for random rubble stone

masonry is hard; sound free

from decay and weathering.

Stones with porous matter or

with boulder skin are rejected.

The size of stones are not less

than 15 cm in any direction.

for the reinforced joint is not less than 4 cm or three times the diameter of the

reinforced rods whichever is greater. For roof slabs, bricks are arranged in

such a way so that the inner edge of the wall and the reinforced joint do not lie

on the same line.

Laying of r einforcement: Reinforcement rods are then laid exactly at the

centre of the joint. The rods do not touch the bricks at any place.

Overlapping of bars are avoided as far as possible by using bars of the

required length, but where this cannot be done a lap of 45 times diameter of

the bar is given with the necessary hooks at the ends and two rods are wired

along the lap.

Laying of mortar: Mortar of cement and sand in the proportion 1:3 is first

mixed dry on a solid, clean platform and then is mixed wet at least three times

by adding clean water gradually and evenly. The mortar is placed into the

gaps in between the bricks within 30 minutes, surrounding the reinforced

rods. Care is taken that bottom of rods in the slabs have the correct cover ofmortar under them. The filling of joints by mortar is carried out continuously

and no portion of mortar is allowed to start its initial set before the

neighboring mortar is in its place.

Curing: The work is not to be disturbed and should be kept wet for at lest 7

days.

Removal of centering: The centering is removed after 10 days without any

jerking of any kind.


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15

Coursed

Rubble Stone

Masonry

Cement and sand for cement

mortar or lime and surkhi

(sand) for lime mortar are of

standard specification.

Same as specified in Random

Rubble Masonry.

Mortar: The ingredients of mortar, cement and sand or lime and surki are

first mixed dry in the specified proportion till of uniform colour on a solid

clean platform and then mixed wet at least three times by adding watergradually and evenly.

Laying: All stones are first thoroughly wetted before laying. The stones are

hammer dressed with wooden mallet on the bed and from all other faces to

enable them to come into close proximity with each other securing close joint.

The walls are carried up truly plumb. Face stone is not narrower than its

height and is tailed back and bond well into the backing. The stones are

arranged to break joint on the face for at least half the height with those of

courses above or below. Stones are so laid that all joints are quite full of

mortar and the thickness of joints does not exceed 20 mm. Interstices between

stones are wedged with stone chips and spalls to avoid thick beds of joints and

mortar. In the interior thickness of the wall, bond stones at least 45 cm longare given one for every half sq m of face so as to approximately provide

through bond of long stones. The masonry is carried out together so as to

maintain uniform height as far as possible. If any part of a wall is required to

be raised in advance, toothing is formed by giving projections to bond with

the wall to be built later.

Curing: The work is to be protected from rain or sun while it is green. At

the end of the days work the topsof walls are left flooded. The masonry is

kept moist on all the faces for at least 7 days.

Laying: All stones are to be thoroughly wetted before laying. Every courseof stone is hammer dressed and laid truly horizontal and every vertical joint is

kept truly vertical. Faces are accurately squared and each face joint is dressed

at right angles. The face stones are laid alternate headers and stretchers. No

pinning is allowed on the face. Each course consists of stones of even

thickness not less than 3 cm and not more than 23 cm. No stones in face are to

have less breadth than height and no stone is tailed into the wall less than its

height. At least1/3

rd of the face stones are tailed into the wall twice their

height. The masonry is carried up regularly and true to plumb. The thickness


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16

of joints are kept so as no to exceed 12 mm. In case plastering or pointing is

not to be carried out, the joints are struck flush and finished at the time of

laying.

Bond or through stones: The stones going through the wall are welldistributed provided in the whole wall by arranging them in a staggered

fashion in successive courses. The intervals of through stones are not be less

than 1.5 m in each course. For walls up to 60 cm thickness, a through stone

is extended from one face of the wall to other. But in case for wall of greater

thickness at least 15 cm side over-lapping headers forming a stone joint is

laid from face to back.

Quoins: Corner stones or quoins are dressed to correct angle. The short bed

of the stone is at least equal to height. The quoins are laid with header and

stretcher in alternative layers.

Curing: Same as described in Random Rubble stone masonry.

Damp Proof Course Coarse aggregate is of clean,

hard and dense stone chips 12

mm down and is washed before

use.

Sand is clean, sharp and coarse

of average 5 mm size and is free

from dust, and dirt and

screened before use.


cement.

All the materials in use

including water proofing

D.P.C. of

cement

concrete should

have a mix of

1:2:4 or

1:11/2:3.

Usual thickness

2.5 cm to 4 cm.

Mixing: Coarse aggregate and sand are measured by volume with gauge

boxes and cement by bag having a weight of 50 kg or volume of 0.0347 cu m.

Some sample tests of cement bags are made at work site to ensure the

specified weight and volume.

The mixing is done on a clean solid platform. Dry coarse aggregate is stacked

evenly on the platform. Sand and cement in the specified quantities at first is

mixed dry till of uniform colour and spread over the stacked coarse aggregate.

The materials are mixed dry till of uniform colour and spread over the

stacked coarse aggregate. The materials are then turned over once without

adding water and then at least further 3 times, adding the required quantity of

water gradually and slowly to give a uniform concrete. Water-proofing

compound Pudlo or Cico @ 5 or 3 per cent by the weight of cement as

specified is mixed with concrete to make it water proof.


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compound are to be of their

respective standard

specifications.

Preparati on of base: The top of the walls on which damp-proof course is to

be laid is constructed with bricks on edge or with frogs of the bricks down.

The top of the plinth bed over which damp-proof course is to be placed is

thoroughly cleaned with a steel brush, washed and wetted before laying thecourse of concrete. Wooden straight edges are fixed on plinth wall having the

same inner width as that of the required with of the D.P.C.

Laying: Damp-proof course may be laid to the full width of the plinth or of

the superstructure as specified in the drawing or specially mentioned.

It is laid to the specified thickness (2.5 cm or 4 cm) over the plinth wall flush

with the floor surface and is not carried across the doorways or such other

openings.

D.P.C. is then consolidated by tamping and leveled both longitudinally and

transversely.

Laying is completed on same day; the joints or breaks are given at the door

opening. The surface of the concrete is roughened and chequered when air

dry so as to form a key for the joint with the brick wall above.

Curing: Damp-proof course is to be kept wet for at least 7 days after laying,

if the brickwork is not ready to proceed further.

But in any case no brickwork is commenced on the freshly laid damp-proof

course unless the D.P.C. has been flooded with water for at least 48 hours.

[Alternatively; the damp proof course may also be of 2 cm thick layer ofcement mortar (1:2) mixed with water-proofing compound or with 5% of

Pudlo by weight of cement. In this case only write the specifications of sand

and cement. The mixing is same as that of cement mortar for brickwork. All

other clauses are same as stated above]

Flooring

Brick on Edge

Flooring

Bricks of the specified strength

are used, conforming to its

Sub-grade: The sub-grade is provided with the slope required for the

flooring.


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standard specification. Broken

bricks are not used in the

flooring except for closing the

line. The bricks are laid on

edge.

Mortar: The mortar used is as

specified.

In case of dry brick flooring,fine sand is filled in the joints.

The sub-grade for flooring may be on concrete. In this case the plinth

masonry off-set are depressed so as to allow the sub-grade concrete to rest on

it.

In case of lime concrete sub-grade, it is allowed to set for seven days.

If the sub-grade is of lean cement concrete, the flooring is commenced within

48 hours of the laying of sub-grade failing which, the surface of sub-grade is

roughened with steel wire brushes without disturbing the concrete. Before

laying the flooring, the concrete sub-grade is made wet and a coat of cement

slurry at the rate of 2 kg per sq m is spread over the prepared sub-base in

order to get a good bond between sub-grade and flooring.

Where concrete sub-grade is not provided, the earth below is properly sloped,

watered, rammed and consolidated.

Before laying the flooring, it is moistened.

Soaking of bri cks: Bricks required for flooring are thoroughly soaked in

stacks before use by spraying clean water sufficiently at regular intervals for

a period of not less than six hours so as to keep wet to the satisfaction of the

Engineer-in Charge. In case the joints are to be filled with sand, the bricks

need not be soaked.

Laying: The bricks are laid on edge in plain, diagonal herring bond or other

pattern as specified or directed.

Bricks are laid on edge on 12 mm thick mortar bed, and each brick isproperly bedded and set home by gently tapping with handled trowel or

wooden mallet. The inside faces are buttered with mortar, before the next

brick is laid and pressed on it. The vertical joints are fully filled from the top

with mortar. The surface of the flooring, during laying, is frequently checked

with a straight edge at least 2 m. long, so as to obtain a true plain surface

with the required slope. Dry brick flooring is laid on a bed of 12 mm thick

mud mortar with the required slope.


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Terrace

Flooring over

brick flat

Artificial

stone flooring

Bricks ballast that will pass

through 3 cm dia. Ring, surki

and lime are of their standardspecifications.

Usual thickness are 2.5 cm.

The ingredients are cement,

The ingredients

are mixed at

first dry andthen wet to the

required

proportion (100

brick ballast:

36 surkhi: 18

lime as are

usual).

1:2:4 or as

specified.

Joints: All bricks are so laid that every joint becomes full of mortar. All face

joints are raked to a minimum depth of 15 mm by raking tool during the

progress of work when the mortar is still green in order to provide proper key

for the pointing or plastering to be done. If plastering or pointing is not

required to be done, the joints are struck flush and finished at the time oflaying. The face of brickwork is cleaned on the same day on which the

brickwork is laid and all mortar droppings removed promptly. For dry brick

flooring joints are as fine as possible and not exceeding 5 mm and are filled

up with fine sand.

Curing: Except dry brick flooring the work is protected form rain by suitable

covering when the mortar is green and is kept constantly moist for a minimum

period of 7 days.

Preparation of base: Excess earth or sand that has been thoroughly

compacted in the plinth is removed to a depth equal to the thickness of the

floor to provide room for this. The bed is then dressed with required slope ofthe floor towards its water outlet. A layer of second class or picked jhama

brick as specially mentioned are then laid with break joints and the small gaps

between them are filled up with local fine sand.

Placing of concrete: The concrete is then laid to the specified thickness and

thoroughly rammed and consolidated into position till the surface is smooth

and no further impression can be made.

During ramming lime water is sprinkled on the surface to keep the concrete

wet. Corners and edges where ramming is difficult are specially to be

consolidated by wooden battens according to the direction of the Engineer-in-

Charge. The surface is checked frequently with spirit level and woodenstraight edge to have a true surface.

Curing: The floor is kept wet for at least a week.

Sub-grade: The sub-grade is provided with the slopes required for the

flooring. Flooring in verandah, kitchen, baths, water-closets and courtyards


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or Cement

concrete

flooring

sand and stone chips.

This are also known as patent

stone flooring when crushed

blast surface slag is used ascoarse aggregate.

Coarse aggregate is stone chips

well graded from 12 mm down,

free from dust, dirt etc. hard andrough.

Sand is coarse 5 mm maximum

size, clean, free from dirt etc.


cement.

All the materials as stated

above and water comply with

their respective standard

specifications.

are invariably to be provided with suitable slope to drain off waste and rain

water. Plinth masonry off-sets are depressed so as to allow the sub-grade

concrete to rest on it.

If the sub-grade consists of lime concrete, it is allowed to set for seven daysand the flooring is laid in the next three days.

If the sub-grade is of lean concrete, the flooring is commenced preferably

within 48 hours of the laying of sub-grade.

The surface of the sub-grade is roughened with steel wire brushes without

disturbing the concrete. The sub-grade may also be R.C.C. slab.

In all cases the surface is cleaned and before laying the flooring, the sub-grade

is wetted with a coat of cement slurry at 2 kg of cement spread over an area of

one sq m so as to get a good bond between the sub-grade and concrete floor.

Mixing: Mixing of concrete is done by hand or by mechanical mixer. In case

of hand mixing the cement and sand are at first mixed dry and this dry

mixture is further mixed with dry coarse aggregate till the coarse aggregate is

well coated with dry mix of cement and sand. Required amount of water - 32

litres per bag of cement as per water cement ratio is added slowly and

gradually to mix the concrete wet to have a uniform plastic mix. The mixture

will have a slump of not more than 4 cm. Concrete for one panel only is

mixed at one lot.

Laying: Flooring of specified thickness are laid in the pattern as given in the

drawings or as directed by the Engineer-in-Charge. The panel is of uniform

size and no dimension of a panel will exceed 2m and the area of panels willnot be more than 2 sq m. The whole operation of laying in one panel is

completed within 30 minutes.

Laying with strips: Normally cement flooring is laid in one operation using

glass or plain asbestos sheet strips at the junction of two panels. This method

ensures uniformity in colour of all the panels and straightness at the junction

of the panels.


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Strips fi xing: 4 mm thick glass strips or 5 mm thick plain asbestos strips are

fixed with their top at proper level, giving required slopes.

Laying without strips: Laying of cement concrete flooring in alternate panels

may be allowed by Engineer-in-Charge in case strips are not to be provided.

Shuttering: The panels are bounded by wooded battens. The battens should

have the same depth as the concrete flooring. These are fixed in position,

with their top at proper level, giving required slopes. The surface of the

battens that come in contact with concrete is oiled with raw linseed oil or a

coat of soap solution may be applied before casting the concrete.

Castin g of concrete: The concrete is placed gently and evenly spread within

the panel and thoroughly compacted with wooden thapies to the required

thickness. The surface is then smoothed with wooden floats. The battens

used for shuttering, are removed on the next day of the laying of cement

concrete. The ends thus exposed are repaired, if damaged, with cementmortar 1 cement: 2 coarse sand, and allowed to set for a minimum period of

24 hours. The alternate panels are then cleaned of dust, mortar-droppings etc.

While laying concrete, care is taken to see that the edges of the previously laid

panels are not damaged and fresh mortar is not splashed over them.

Finishing: The surface is left for some time, till moisture disappears from it.

Excessive trowelling is avoided. Use of dry cement or cement and sand

mixture sprinkled on the surface to stiffen the concrete or absorb excessive

moisture, is not permitted. Fresh quantity of cement at 2.0 kg of cement is

mixed with water to form thick slurry and spread over an area of one sq m of

flooring while the concrete is still green. The cement slurry is then properly

pressed and finished smooth. The men engaged in finishing operation areprovided with raised wooden platform to sit on, so as to prevent damage to

new work.

Curing: the curing is done for a minimum period of ten days. Curing will not

commence until the top layer has hardened. Covering with empty cement

gunnies are avoided as the colour is likely to be bleached with the remnants of

cement matter from the bags.


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Patent stone

floor

Cement

concrete

flooring with

topping of red

oxide of iron

The proportion

of mix is 1:2:4

(4 graded stone

chips 12.5 mm

nominal gauge)by volume

unless

otherwise

described.

The preparation and method of construction is the same as that of the

artificial stone or cement concrete floor. The only difference is that the

coarse aggregate is of crushed blast furnace slag.

Sub-grade: it is as specified for artificial stone flooring.

Under layer: The under layer of flooring is of cement concrete of specified

thickness. As regards cement concrete the work is carried out in the manner

conforming to the specification of artificial stone flooring. As regards laying

the work, it is carried out in the manner specified in artificial stone flooring

except that:

a. the wooden battens used for shuttering are to be the heightof both, under and top layers of the floor;

b. the under layer is roughened with 2 mm deep diagonal linesat 7.5 cm centres both ways with a scratching tool to form akey for the finishing coat of red oxide of iron, no cement

slurry being added to the concrete surface, and

c. The battens are removed only 24 hours after the top layerhas been laid. The surface of the under layer is left even

and true to slope.

Top layer: This consists of uniform and smooth layer of plaster of specified

thickness (generally 10 mm) and of mix 1:3 (1 cement: 3 coarse sand), unless

otherwise specified, finished with a floating coat of neat cement. Unless

mentioned 3.5 kg. of red oxide of approved quality to 50 kg of cement is to be

mixed thoroughly by hand till of uniform colour and then sand added and

mixed. The full quantity of dry mortar required for a room is prepared in onelot in order to ensure uniform colour, water is then added to form a stiff paste

in the usual manner as and when required.

Laying: The top layer is laid, the following day after the under layer has

been laid. The plaster is done to a uniform thickness, of 10 mm and finished

smooth with cement slurry (2.0 kg of cement red oxide mix per square meter

of flooring mixed in the ratio used) for the plaster. The surface is then

brought to a fine polish by use of polishing stones.


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Terrazzo or

Mosaic

Flooring

The terrazzo floor consists of

two layers, the under layer

usually of 20 mm thick cement

concrete 1:2:4 or as specifiedand the top layer usually 6 mm

thick terrazzo consisting of

cement, marble powder, marble

chips in the specified proportion

and water.

The battens used for shuttering of panels are removed the next day after

laying of the top layer and broken edges repaired with the same coloured

mortar as in plaster.

Curing: The curing is done for a minimum period of ten days. Curing is not

to commence until top layer has hardened. Covering with empty cement

gunnies are avoided as the colour is likely to be bleached with the remnant of

cement matter from the bags.

Under layer: Coarse aggregate for cement concrete is of granite stone chips

of 12 mm gauge, sand is coarse, cement is fresh Portland cement each of them

with their standard specification. Cement concrete of specified mix usually

1:2:4 is prepared following the standard specification as for cement concretework. The bed for the under layer is cleaned and cement slurry @ 2.0 kg per

sq. m is applied before laying of under layer over the cement concrete or

R.C.C. surface. The whole area is divided into panels of uniform size by 4 to

6 mm glass strips or 2 mm aluminum strips with their tops at proper level,

giving slopes. Each panel will not exceed 2 sq. m in area and 2 m in length

for inside situations. In exposed situations the length of any side of the panel

will not be more than 1.25 metres. Cement slurry @ 2.0 kg per sq m is

applied before laying of under bed over concrete or R.C.C. surface. The

concrete is laid within the panel and thoroughly compacted with wooden

thapies with the required thickness generally 20 mm and smoothed with

wooden floats.

Top layer: The mix for terrazzo topping will consist of cement with or without

pigment, marble powder, marble chips and water. The marble chips can be

white or pink, black, yellow or any other colour as specified. These are hard,

sound dense and homogeneous in texture. These are uniform in colour and

free from stains, cracks, decay and weathering. For 6 mm to top layer, size of


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marble chips are 1 to 2 mm. The minimum thickness of topping is not less

than 11/3times the maximum size of chips. The cement to be used is ordinary

grey cement or white cement of required shade as specified. Colouring

matter where specified is mixed dry thoroughly with the cement and marble

powder and then marble chips added and mixed as specified. The fullquantity of dry mixture of mortar required for a room is prepared in a lot in

order to ensure a uniform colour.

The mixture is stored in a dry place and well covered and protected from

moisture. The dry mortar is homogeneous and stiff and contains justsufficient water to make it workable.

The terrazzo topping is laid while the under layer is still plastic, but has

hardened, this are normally achieved between 18 to 24 hours after the under

layer has been laid. A cement slurry preferably of the same colour as the

topping is be brushed on the surface immediately before laying is commenced.

It is laid to a uniform thickness slightly more than that specif ied in order toget the specified finished thickness after rubbing. The surface of the top layer

is trowelled over, pressed and brought true to required level by a straight

edge and steel floats in such a manner that the maximum amount of marble

chips come up and spread uniformly over the surface.

Polishing, Curing and Finishing: Polishing is done by machine. About 36

hours after laying the top layer the surface is watered and ground evenly with

machine fitted with rapid cutting grit blocks (carborundum stone) of coarse

grade (No. 60) till the marble chips are evenly exposed and the floor is

smooth. After first grinding, the surface is thoroughly washed to remove all

grinding mud and covered with a grout of cement and colouring matter in

same mix and proportion as the topping in order to fill any pin holes thatappear. The surface is allowed to cure for 5 to 7 days and then ground with

machine fitted with fine grit blocks (No. 120). The surface is cleaned and

repaired as before and allowed to cure again for 3 to 5 days. Finally the third

grinding is done with machine fitted with finest grade grit blocks (No. 320) to

get even and smooth surface without pin holes. The finished surface should

show the marble chips evenly exposed.

Where use of machinefor polishing is not feasible rubbing, and polishing is


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Pre-cast

terrazzo tile

Flooring

Terrazzo tiles generally

conform to IS-1237 (modified

up to date). The specific sizes

of tiles are used. When the

nominal size of a tile is 20 cm x

20 cm the actual size is 19.85

cm X 29. 85 cm and thicknessare not less than 25 mm.

Tolerances on length and

breadth are plus or minus one

millimeter; tolerance on

thickness are plus or minus 5

mm.

The tiles are manufactured

under hydraulic pressure of not

less than 140 kg per square

centimeter and are given the

first grinding with machinebefore delivery to site. The

proportion of cement to

aggregate in the backing of the

tiles are not leaner than 1:3 by

weight. The finished thickness

of the upper layer is not less

then 5 mm for size of marble

chips from the smallest up to 6

done by hand in the same manner as specified for machine polishing except

that carborundum stone is grade No. 60 for 1st

rubbing, grade No. 80 for 2nd

rubbing and grade No. 120 for final rubbing and polishing.

After the final polish, oxalic acid is dusted over the surface @ 33 gm persquare metre sprinkled with water and rubbed hard with a pad of woolen rags.

The following day, the floor is wiped with a moist ran and dried with a soft

cloth and finished clean.

Preparation of Surface: Sub-grade concrete or the R.C.C. slab on which the

tiles are to be laid is cleaned, wetted and mopped. The bedding for the tiles

are of lime mortar of either 1 lime putty: 1surkhi:2 coarse sand or 1 lime

putty: 3 surki or 1 lime putty: 3 coarse sand. The ingredients are thoroughly

mixed by volume in dry form. Care is taken to ensure that there are no hard

lumps present. Water is then added and the ingredients thoroughly mixed.

The average thickness of the bedding mortar is 30 mm and the thickness atany place is not less than 10 mm.

Laying: Lime mortar bedding is spread, tamped and corrected to proper

levels and allowed to harden for a day before the tiles are set. Over this

bedding, neat grey cement slurry of honey like consistency is spread at the

rate of 4.4 dg of cement per square meter over such an area as would

accommodate about twenty tiles. Tiles are washed clean and are fixed in this

grout one after another, each tile being gently tapped with a wooden mallet till

it is evenly bedded, and in level with the adjoining tiles. The joints are kept as

thin as possible not exceeding 1.5 mm and in straight lines or to suit the

required pattern. The surface of the flooring is checked with a straight edge

during laying of each tile, so as to obtain a true surface with the requiredslope. When full size tiles cannot be fixed, these are cut to the required size

with straight edge, rubbed smooth to ensure a straight and true joint. Tiles

which are fixed in the floor adjoining the wall enter not less than 12 mm

under the skirting or dado. After the tiles have been laid, surplus cement

grout that may have come out of the joint is cleaned off.

Curing, Polishing and F inishing: The day after tiles are laid all joints are

cleaned to a depth of 5 mm and all dust and loose mortar removed. Joints are


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26

mm. For other size of marble

chips, the finished thickness are

as specially mentioned.

then grounded with grey or white cement mixed with pigment to match the

shade of the topping of the wearing layer of the tiles. The same cement slurry

is applied to the entire surface of the tiles in a thin coat with a view to protect

the surface form abrasive damage and fill the pin holes that may exist on the

surface.

The floor is then kept wet for a minimum period of 7 days. The surface is

thereafter grounded evenly with machine fitted with coarse grade grit blocks

(No. 60). Water is used profusely during grinding. After grinding, the

surface is thoroughly washed to remove all grinded mud, cleaned andmopped. It is then covered with a thin coat of cement slurry mixed with

pigment as applied after laying the tiles. The surface is again cured. The

second grinding is then carried out with machine fitted with fine grade grit

blocks (No. 120). The final grinding with machine fitted with the finest grade

grit blocks (No. 320) is carried out the day after the second grinding as

described above. For small areas or where circumstances so require, hand

polishing may be permitted in lieu of machine polishing after laying. Forhand polishing, the following carborundrum stones are used: 1

stgrinding No.

60; second grinding, medium grade No. 80; and for final grinding, fine grade

No. 120. In all respects the process are similar to machine polishing.

After the final polish, oxalic acid is dusted over the surface at the rate for 33

gm per square metre sprinkled with water and rubbed hard with a pad of

woolen rags. The following day the floor is wiped with a moist rag and dried

with a soft cloth and finished clean.

Dado & Skirting

Terrazzo

Tiles

Terrazzo Tiles in Rises of Steps, Skirting and Dado:

Terrazzo Tiles: Same as specified in 15-39. The minimum finishedthickness are 12 mm. When the bigger sized chips are used, the tiles are not

less than 20 mm thick.

Preparation of surface: The joints are raked out to a depth of at least 15 mm

in masonry walls, while the masonry is being laid. In case of concrete walls,

the surfaces are roughened by hacking. The surface is cleaned thoroughly

and washed with water.


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Glazed Tiles

Laying: 12 mm thick cement mortar 1 cement: 3 coarse sand or mix as

specified is then applied and allowed to harden. The plaster is roughened with

wire brushes or by scratching diagonal lines at close intervals. The back of

tiles are buttered with a coat of grey cement slurry and edges with grey or

white cement slurry with or without pigment to match the shade of tiles, andset in the bedding mortar. The lines are then tamped and corrected to proper

planes and lines. The tiles are set in the required pattern and butt jointed. The

joints are as fine as possible. Top of skirting or dado is truly horizontal and

joints truly vertical except where otherwise mentioned.

The rises of steps, skirting or dado shall rest on the top of the tread or

flooring. Where full size tiles cannot be fixed, the tiles are cut to the required

size and their edges rubbed smooth.

Curing, Polishing and Finishing: Same as in article 15-39 shall hold good

as far as applicable. Polishing is done by hand.

Glazed Til es in Skir ting and Dado: Glazed Tiles: The tiles are of approved

made confirming to IS 777-1970. They are flat, and true to shape and free

from cracks, crazing spots, chipped edges and corners. The glazing is of

uniform shade.

The tiles are of nominal sizes as 150 x 150 mm and 100 x 100 mm or as

specified. The thickness of the tiles are 5 mm or 6 mm as specified. The top

of the tiles are completely free from glaze in order that the tile may adhere

properly to the base. The edges of the tiles are free from glaze, however, any

glaze it unavoidable, is permissible on any one edge of the tile.

Preparation of Surface: While the masonry is being laid, the joints are rakedout to a depth of at least 15 mm in masonry wall. In case of concrete wall, the

surfaces are roughened with wire brushes or by scratching diagonal at close

intervals.

Laying: 12 mm thick plaster of cement mortar 1 cement: 3 coarse sand or

mix as specified is applied and allowed to harden. The plaster is roughened

with were brushes or by scratching diagonal at close intervals.


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Cement

plaster

skirting

finished with

red oxide of

iron

(a band of plaster at thebottom of wall not

exceeding 30 cm in

height above the floor is

classified as skirting):

iron


cement and sand is medium

quality, clean, free from

organic matter and salts. Red

oxide is of approved quality.

All the materials including

water is of I.S. specification.

The tiles should be soaked in water, washed clean, and a coat of cement

slurry applied liberally at the back of tiles and set in the bedding mortar. The

tiles are tamped and corrected to proper plane and lines. The tiles are set in

the required pattern and butt jointed. The joints are as fine as possible. Top

of skirting of dado is truly horizontal and joints truly vertical unless speciallymentioned. Skirting and dado shall rest on the top of the flooring. Where full

size tiles cannot be fixed these is cut to the required size and their edges

rubbed smooth.

Curing and Finishing: The joints are cleaned off the grey cement grout withwire brush or trowel to a depth of 2 mm to 3 mm and all dust and loose mortar

removed. Joints are then flush pointed with white cement added with

pigments if required to match the colour of tiles. The surface is kept wet for 7

days. After curing, the surface shall not sound hollow when tapped with a

wooden mallet.

Thickness: The thickness of the skirting is measured exclusive the thicknessof key i.e. grooves or open joints in brickwork. The average thickness should

be regulated at the time of plastering by keeping suitable thickness of the

gauges. Extra thickness required in dubbing behind rounding of corners at

junctions of wall is ignored.

Preparation of wall surface: The joints are raked out to a depth of at least

15 mm in masonry wall, while the masonry is being laid. In case of concrete

walls, the surfaces are roughened by hacking. The surface is cleaned

thoroughly, washed with water and kept wet before skirting is commenced.

Application of under coat: The under coat of skirting is of cement plaster of

the thickness and mix described in the item. The cement plaster for undercoat is laid immediately after this are prepared. The under coat is finished

rough with a scratching tool to form a key for the top coat.

Mortar for top coat: This shall consist of uniform and smooth layer of

plaster of specified thickness and of mix 1: 3 (1 cement: 3 coarse sand) or as

specified. Unless specified 3.5 kg of red oxide to 50 kg of cement (i.e. per

bag) is mixed thoroughly with the cement and then sand added and mixed.

The full quantity of dry mortar required for a room is prepared in one lot in


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order to ensure uniform colour. Wet mortar is prepared in the usual manner

as and when required.

Application of top coat: The top coat is done the next day after the under

coat has been applied. The plaster is done to the thickness specified andfinished smooth, by application of cement red oxide mix at the rate of 1.0 kg

sq m of surface. The ratio is 3.5 kg of red oxide to 50 kg of cement if not

otherwise mentioned. When the surface has hardened sufficiently it is brought

to a fine polish by use of polishing stones.

Woodwork

Doors and

window

frames

Doors and

Timber is of teak, sal, deodar

etc. as mentioned, well

seasoned, dry, free from sap,

knots, crack or any other

defects or diseases. It is sawn

in the direction of the grains.

Sawing is truly straight andsquare. The scantling is

planned smooth and accurate to

the full dimensions, rebates,

roundings and mouldings as

shown in the drawing made,

before assembling. Patching or

plugging of any kind is not

permitted except as provided.

Specified timber is used, and it

Joints: These are mortise and tenon type, simple, neat and strong. Mortise

and tenon joints shall fit in fully and accurately without wedging or filling.

The joints are glued framed, put together and pinned with hardwood or

bamboo pins not less than 10 mm dia. After frames are put together pressed in

position by means of a press.

Surface Tr eatment: Wood work is not painted, oiled or otherwise treated

before it has been approved by the Engineer-in-Charge. All portions of

timber abutting against masonry or concrete or embedded in ground is

painted with approved wood primer or with boiling coal tar.

Gluing of Joints: The contract surface of tenon and mortise joints are treated

before putting together with bulk type synthetic resin adhesive of a make

approved by the Engineer-in-Charge.

Fixi ng in position: The frame is placed in position truly vertical before the

masonry reaches half the highest of the opening with iron clamps or as

directed by the Engineer-in-Charge. In case of door frames without sills, thevertical members are embedded in the flooring to a depth of 40 mm or as

directed by the Engineer-in-Charge. The door frames without sills while

being placed in position, is suitably strutted and wedged in order to prevent

warping during construction. The frames shall also be protected from

damage, during construction.

Joinery work: All pieces are accurately cut and planned smooth to the full


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window

shutters

is well seasoned, dry, and free

from sap, knots crack or any

other defects or disease.

Patching or plugging of any

kind is not permitted except asprovided.

dimension. All members of the shutters are straight without any warp or bow

and shall have smooth, well planned faces at right angles to each other. In

case of paneled shutters the corners and edges of panels are finished into

grooves to the full depth of the groove leaving an air space of 1.5 mm and the

faces are closely fitted to the sides of the grove. In case of glazed shutter,sash bars shall have mitered joints with styles. Styles and rails are properly

and accurately mortised and tenoned. Rails which are more than 180 mm in

width shall have two tenons. Styles and end rails of shutters are made out of

one piece only. The tenons shall pass through styles for at least3/4th of the

width of the style. When assembling a leaf, styles are left projection as ahorn. The styles and rails shall have 12 mm groove in paneled portion for the

panel to fit in.

The depth of rebate in frames for housing the shutters shall in all cases be

1.25 cm and the rebate in shutters for closing in double shutter doors or

windows are not less then 2 mm. The rebate is splayed. The joints are

pressed, and secured by bamboo pins of about 6 mm diameter. The horns ofstyles are sawn off.

For battened shutters: Plank for battens are 20 mm thick unless otherwise

specified and of uniform width of 125 to 175 mm. These is planned and made

smooth, and provided with minimum 12 mm rebated joints,. The joint lines

are chamfered. Unless otherwise specified the battens for ledges and Braces

are 30 mm thick and fixed with the battens on the inside face of shutter with

minimum two number 50 mm long wood screws per batten. The ledges are

225 mm wide and braces 175 mm wide, unless otherwise specified. The

braces shall incline downwards towards the side on which the door is being

hung.

Glui ng of joints for panell ed or Gl azed shutters: The contact surfaces of

tenon and mortise joints are treated before putting together with bulk type

synthetic resin adhesive of a make approved by the Engineer-in-Charge.

Shutters are not painted, oiled or otherwise treated, before these are fixed in

position and passed by the Engineer-in-Charge.

For glazed shutters, mounting and glazing bars are tub-tenoned to the


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maximum depth which the size of the member world permit or to a depth of 25

mm, whichever is less.

Fittings: Details of fittings to be provided is as per the schedule of fittings

supplied by the Engineer-in-Charge in each case. The cost of providing andfixing shutters shall include the cost of hinges and necessary screws for fixing

the same. All other fittings are enumerated and paid for separately. The

fittings shall conform to their respective IS specifications. Where fittings are

stipulated to be supplied by the department free of cost, screws for fixing the

fittings are provided by the contractor and nothing extra will be paid for thesame.

Steel doors and

windows

Steel doors and window are

manufactured using rolled steel

sections of the weights

specified in IS: 1038 latest

issue. They is fixed, centrehung, top hung, bottom hung or

composite as specified. The

steel is of S.T. 32-0 grade

conforming to IS: 1977 or latest

issue.

Size: The steel doors and

windows are according to the

specified sizes and design. The

sizes of doors and windows are

calculated so as to allow 1.25

cm clearance on all four sidesof openings to allow for easy

fitting of door, windows and

ventilators into opening. The

actual sizes of doors, windows

and ventilators shall not vary

by more than 1.5 mm form

those given in drawing.

Fabrication: Both the fixed and opening frames are constructed of sections

which have been cut to length and mitered. The corners of fixed and opening

frames are welded to form a solid-fused welded joint conforming to the

requirements given below. All frames are square and flat. The process of

welding adopted may be flash or butt welding or any other suitable methodwhich gives the desired results.

Requirements of welded joints: Visual inspection test: when two opposite

corners of the frame are cut, paint removed and inspected, the joint shall

conform to the following:

(i) Welds should have been made all along the place of meetingmembers.

(ii) Welds should have been properly ground, and(iii) Complete cross section of the corner is checked up to see that

the joint is completely solid and there is no cavity visible.

Mi cro and macro examinations: From the two opposite corners obtained for

visual test, the flanges of the sections are cut with the help of a saw. The cut

surfaces of the remaining portions are polished, etched and examined. The

polished and etched faces of the weld and the base metal is free from cracks

and fairly free from under cutting, overlaps, gross porosity and entrapped

slag.

Fillet weld test: The fillet weld in the remaining portion of the joint obtained


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is fractured by hammering. The fractured surfaces are free from slag porosity,

crack, penetration defects and fusion defects.

Door: The hinge pin is of electro-galvanized steel of suitable thickness and

size. In case of double doors, the first closing leaf is the left hand leaf lockingat the door from the push side. The first closing shutter shall have a

concealed steel bolt at top and bottom. The bolts are so constructed as not to

work loose or drop by their own weight. Single and double shutter door is

provided with a three way bolting device.

Windows: For fixed windows the frames are fabricated as described in

fabrication. But side hung windows for fixing steel hinges slots are cut in the

fixed frame and hinges inserted inside and welded to the frame. The hinges

are of projecting types the hinge pin is of galvanized steel.

Friction hinges are provided for side hung windows shutters if specified. The

handle plate is welded, screwed or riveted to the opening frame in such amanner that it should be fixed before it is glazed and should not be easily

removable after glazing. The handles shall have a two point nose which shall

engage with a brass striking plate on the fixed frame in a slightly opened

position as well as in the closed position.

The boss of the handle shall incorporate a friction device to prevent handle

from dropping under its own weight and the assembly is so designed that the

rotation of the handle may not cause it to unscrew from the pin. The strike

plate is so designed and fixed in such a position in relation to the handle that

with the latter bearing against it stops; there is adequate light fit between

casement and outer frame. In case where nonfriction type hinges are

provided, the windows are fitted with peg stags which are either of blackoxidized steel or as specified, 300 mm long with steel peg and locking

brackets. The pegs stays have three holes to open the side hung casement in

three different angles. Side hung casement fitted with friction hinges is not

provided with a peg stay.

Galvanizing: All steel surfaces are thoroughly cleaned of rust, scale and dirt.

Where so specified, the steel surfaces are treated for rust-proofing by the hot

dip, zinc spray or electro-galvanizing process. The rate is exclusive of final


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finishing coats but shall include the priming coat.

Fixing: Where openings are flush and with a rendered finish a clearance of

1.25 cm is provided between the steel frame and opening. In the case of

external masonry finish Fair-Faced and with rebated jambs a minimum1.25 cm clearance between frame and opening is provided.

Plastering and

finishing

Cement

Plastering

Cement

plastering

with a

floating coat

of neat

cement



quality, cleaned, free from

organic matter or salts. All the

materials including water are of

standard specification.

Preparation of mortar: Thematerials are at first mixed dry

thoroughly till uniform in

colour in the required

proportion and then is mixed

wet adding water slowly and

gradually for at least four times

to give a uniform paste. Only

as much material is prepared at

a time as can be used within the

initial setting time (30 minutes)

of cement.



quality, cleaned, free from

organic matter or salts. All the

materials including water are of

standard specification

Preparation of surface: The surface of the wall is brushed, cleaned, washed,

watered and wetted with water before plastering. In case of cement plaster on

cement concrete the face is lightly roughened, cleaned, washed and wetted.

To ensure uniform thickness of plaster as specified, narrow strips of about 10

cm wide plaster is applied first a distance of about 1 m centres and the gaps

between such strips shall immediately be filled up with mortar.

Laying: The plastering is started from the top and worked towards theground. The whole surface is made flush with wooden straight edges and

rubbed thoroughly with wooden floats to ensure an even surface. Rounding

of corners if desired by the Engineer-in-Charge is carried out in one operation.

Curing: Plastering surface is kept wet by sprinkling water after 12 hours for

at least 7 days and is protected from rain or sun.

State the specification of cement plaster except for the additional floating

coat which is carried out as below:

When the plaster has been brought to a true surface with wooden straight

edge it is uniformly treated over its entire area with a paste of neat cement

and rubbed smooth, so that the whole surface is covered with neat cement

coating. The quantity of cement applied for floating coat is 1.0 kg per sq m.

Smooth finishing is completed with trowel immediately and in no case later


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6 mm thick

cement

plaster in

ceiling

than half an hour of adding water to the plaster mix.

(Note: The floating coat may be of red-oxide. In that case 3.5 kg of red oxide

to 50 kg of cement if not otherwise mentioned is mixed dry and is applied at

the rate of 1.0 kg

Documents

Specification and Estimation Lecture-5