estimating &quantity surveying.pdf

By :Sushant Sharma

ESTIMATION ANDQUANTITY

SURVEYING

Lecturer - Sushant [email protected]

09910039373

mailto:sushant_sharma1:@yahoo.com

CONTENTS1) DEFINITION2) WHY QUANTITY SURVEYING IS REQUIRED3) SCOPE OF WORK4) QUANTITY SURVEYING SERVICES

a) PRE-TENDER PHASEb) POST-TENDER PHASE

5) TAKING OFF QUANTITIES-PROCESS AND PRINCIPLE6) TAKING OFF QUANTITIES

1) METHOD OF MEASUREMENT FOR BUILDING PROJECT7) ABSTRACTING AND ITS APPLICATION8) BILLING & ROLE OF BOQ

9) METHODS OF MEASUREMENT OF WORKS –IN ACCORDANCE TO IS:1200a) EARTHWORKb) CONCRETEc) FORMWORKd) STEEL REINFORCEMENTe) BRICKWORK

10) DETAILED SPECIFICATIONS1) EXCAVATION/ EARTHWORKS2) CEMENT CONCRETE WORKS3) BRICKWORKS4) PLASTERING5) PAINTING

11) ANALYSIS OF RATES , USE OF COST DATAIN ESTIMATION

1. DEFINEQuantity Surveying

Estimation of quantities &cost of different items of work to be executed in aProject.

At the conceptual stage such estimation is done on the basis of conceptualdrawings or in case of any non-availability of such drawings, it is done onthumb-rule basis utilizing expertise and experience of specialists.

At the execution stage the quantities are calculated based on the constructiondrawings.

In general we can describe quantity survey as follows:In general we can describe quantity survey as follows:1. Description and preparation of the bill of quantities and its items required for

the tender.2. Preparation of the site material, material types, and material distribution

Accuracy ,thoroughness and ability to reconcile quantity and cost at everypoint of time are the important qualities of a Good Quantity Surveyor.

2. WHY QUANTITY SURVEYING IS REQUIRED

CONSTRUCTION PROJECT

To ascertain theCommercialViability of suchprojectif implemented

Certification ofExecutionCost ofProject

Derivation of theFinal ProjectCost

Comparison of Estimatedvis-à-visExecuted Cost

Analysis of reasonsfor Variation

Data bank for futuresimilar Project

Preparation ofInitialEstimated Costof Project

3. SCOPE OF WORK

Architects

Financers

Engineers / Consultants

Insurers

Contractors / Subcontractors

Solicitors

Nodal Agencies

Statutory Authorities

Owner / Employer

Quantity Surveyors

Project Viability Study / Evaluation Stage

InfrastructuresCoverage.

This could be acall out area.

Role of quantity surveyors during various stages of ProjectRole of quantity surveyors during various stages of Project

Stage 1 Consultant office

• :During the preparation ofbidding documents :

• Preparation of the BOQ from thedesign drawing -Part of biddingdocuments.

• Preparation of cost estimate foritems listed in BOQ

• Review and check the bidssubmitted from bidders.

• Preparation of the lists of thecontents of bids received.

• Sharing in evaluation andpreparation of t recommendationto award the contract to besubmitted to owner.

Stage 2 :Stage 2 :During the supervision of the constructionDuring the supervision of the construction

Review and checking the payments submitted from thecontractor.Preparation of the reports about the conformity of thequantities items with contract documents.During the implementation :During the implementation :Review and checking the BOQ at the starting of the work.Prepare the eng. Measurement for the quantities of the finishedworks.Prepare lists of the site needs (material, workers, technicians)Calculate the remuneration of the subcontractors, workers,equipments,…etc.Prepare the payment statementsPrepare the detailed reports describing the situation of the itemsquantities, (plus or minus the contract BOQ)

Stage 3 :Review andcheck thefinancialpayments.

7

Required Skills of a Quantity SurveyorRequired Skills of a Quantity Surveyor

Ability to understand the drawings details, design drawings,shop drawings, as built ).

Excellent knowledge of the calculation of the areas andvolumes, knowledge of fees of workers e /technicians/ , rulesand law of the contracts,

In addition to the knowledge of related financial issues/ taxes,banks transactions, insurances and its implication.

Knowledge of the productivity of the workers and technicians.

4. QUANTITY SURVEYING SERVICESQuantity Surveying services are availed intotwo phases namely :

Pre-Tender PhasePost-Tender Phase

Feasibility and market studies.

Preliminary cost planning.

Procurement advice at concept design stage.

Cost management during design development.

Value Engineering.

Life cycle costing.

Preparation of tender documents.

Schedule of materials.

Contract administration.

Pre-Tender Phase

Soliciting of competitive bids and offers with technical proposal.

Optimization of superior technical proposal, capability of bidders and price

evaluation.

Preparation of selected panel of preferred bidders.

Negotiation with preferred bidders.

Clients’ benefit from accurate interim valuations of the work in progress.

Settlement of rational interim payments to contracts for progress of work.

Projection of Timely financial statements.

Estimation of final revised cost to completion.

Settlement of the final account of contractors.

Post-Tender Phase

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The process

5. Taking Off Quantities

· Taking off is the process of measuring dimensions fromworking drawings and recording them in a systematic andconcise manner along with the description of each item.

Booking of Dimensions· The golden rule of booking dimensions is to record length first,

the breadth or width second and height / depth or thicknessthird and last.

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CENTRE LINE

TRENCH TRENCH

230

BRICKWORKIN CEMENT MORTAR (1:6)

PCC (1:5:10)

200SECTION800

3230

4030

2430

6000

3000

6230

7030

5430

1000

Y Z

X

14

Item Description of Item Unit No. Length Breadth / Height / QuantityNumber Width Depth

BY CENTRE LINE METHODTotal Length RM 2 6.23 12.46

RM 2 3.23 6.46RM 18.92

1 Excavation in Trench Cum 1 18.92 0.80 1.00 15.142 PCC (1:5:10) Cum 1 18.92 0.80 0.20 3.033 Brickwork in CM 1:6 Cum 1 18.92 0.23 0.80 3.48

IN and OUT METHOD1 Excavation in Trench Cum 2 7.03 0.80 1.00 11.25

Cum 2 2.43 0.80 1.00 3.8915.14

2 PCC (1:5:10) Cum 2 7.03 0.80 0.20 2.25Cum 2 2.43 0.80 0.20 0.78

3.033 Brickwork in CM 1:6 Cum 2 6.46 0.23 0.80 2.38

Cum 2 3.00 0.23 0.80 1.103.48

Taking Off Quantities

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There are as may as six distinct forms of measurements :

Cubic items0.32 Cum RCC 1:2:4 with 20mm graded stone aggregate in column below ground level.

Square items30.00 Sqm half brick wall in cement mortar 1:4 in super-structure in ground floor.

Lineal or run items90.00 Running Meter 900 mm dia NP3 RCC hume pipe.

Numbers or enumerated items10 Nos. Telephone connections with STD facility.“Or” 3840 Vehicle Days of hard top cars ambassador.“Or” providing 1 wireless system.“Or” 32 Months for maintenance of wireless system.

Provisional sumAllow provisional sum of Rs 2,000/= for site clearance.

Prime cost sumProvide prime cost sum of Rs 2,000/= for electrical tube light fittings to be provided by

specialist firm. Add for overhead and profit.

The Process (contd.)

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Principles and Procedure of Taking Off

The “taker off “ should look on the drawing when received fromEmployer / Consultant / Architect and visualize the work entailed forclear understanding of the job and drawings.

After looking over the drawings and checking plans, elevations,sections and details if any are in agreement with one another. Itshould be checked that each overall dimensions agrees with the totalroom dimensions.

If the discrepancy is clearly the result of some slight clerical error, thedrawing should be corrected and in case serious error is discovered,the architect should be informed and correct drawings obtained.

After having done the above preliminary work the “taker off” will be ina position to start the actual operation of taking off quantities indefinite order.

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1. English Method:1. Taking off (dimension from the drawings)2. Grouping them3. Billing or Bill of quantities

2. PWD Method1. Taking out (dimensions from the relevant drawings )2. Squaring the dimensions3. Abstracting

Methods of Taking off quantities

Timesing Dimensions Squaring Descriptions onof items

Comparison between English Method& PWD Method

English Method• The quantities of items of work

are worked out in the order oftheir execution

• Grouping of items are notcarried out

• Chances of omitting anymeasurement of items of workare very less

• Method is tedious &timeconsuming

• Followed by MES of GOI• Computation carried out in duo

decimals

PWD Method• The quantities of items of works

are determined in the sequenceof measurement.

• Grouping of items are carriedout

• Possibilities of missing some ofthe items of work

• Method is simple , easy &takesless time

• Followed by PWD &CPWD• Computations are in decimals

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Drg. register – Architect &structuralChecking of architectural drg w.r.t building dimensions & correlated tostructural drg.Site visit- GL’s , Measurement of compound wall.- Marking of cmpd wall/Location of Permanent benchmark, Main drain location, Important bldg,road position , Cutting /filling reqd, Trial pit details , Cutting of treesshifting of services.Major elements in the buildingDrgs list requiredMaterial specificationsMeasurement as per sequence of work.Measurement as per fixed directionWastageDimension in measurement to be checked as per drawing.

6. Method of Taking off for Residential Building

BUILDING WORKS

StructuralWorks

Civil Works ExternalWorks

MEP HVAC Interiors

•Substructure•Superstructure

•Envelope/Enclosures•Internal/External Finishes•Water Proofing•Joinery•ArchitecturalElements

•Landdevelopment/SiteGrading•Landscaping/Horticulture•Storm WaterDrainage/ Harvesting•Roads/Pavements•Water Supply•Sewer Network•Area Lighting•Boundary Protection

•MechanicalSystem•ElectricalSystem•PlumbingSystem•Fire System

•SecuritySystem•(LV) Systems

•Heating•Ventilation•AirConditioning•Air Cooling

•InternalFurnishing•SuspendedCeiling•Acoustics•Illumination

6. Method of Taking off for Residential Building

Taking off for Residential Building

Perform Quantity take off for(i) Excavation Works(ii) PCC (150mm thck , 1:3:6 in foundation )

All dimensions specified are outer to outer dimensions of the wall

Taking off for Residential Building

Perform Quantity take off for(i) Half brick thick wall

OWNER / CONSULTANT / ARCHITECTS

Issued Drawings from Owner / Consultant / Architect

Study of Issued Drawings

Evaluation of nature of job

Tallying of dimensions from various drawings

Note discrepancies, if any, in various drawings

Discrepancies ofminor nature

Discrepancies ofserious nature

Discuss inClientslocaloffice

Incorporatein drawings

Refer to

Owner /

Consultant /

Architect

PRINCIPLES & PROCEDURE OF TAKING OFF

Decision

No Discrepancy

Ready for Quantitytake off

Take off of Quantity fromcorrected drawings

Review

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The Process (contd.)7. Abstracting

· The process by means of which the quantities ofitems of identical character and description arecollected from “take off sheets”, totaled anddeduction made in order to arrive at the net totalquantities of respective items and in trade-wiseorder is called abstracting.

Forms the basis for preparation of BOQTrade wise – Trade divided in subsection –

Concrete/ Brickwork /Plastering

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Item Description of Item Unit No. Length Breadth / Height / Quantity RemarksNumber Width Depth

1 Excavation ….For Office Building

In Foundation Cum 15.25 From Sheet # 1For Septic Tank Cum 12.23 From Sheet # 7For Soak Pit Cum 4.65 From Sheet # 8Total Cum 32.13

2 PCC (1:5:10) …For Office Building


3 Brickwork in CM 1:6 … upto Ground LevelFor Office Building


4 Backfilling …For Office Building

Excavation quantity Cum 32.13 From Item # 1Less for PCC 1:5:10 Cum 6.43- From Item # 2Less for Brickwork Cum 7.14- From Item # 3Total Cum 18.56

7. Abstracting

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The Process (contd.)8. Billing

Purpose – Prepare BOQ for Contractors to quote

It is a claim for the amount of work done or materials supplied. Itconsists of –a) Work Order or Agreement No.b) Item No.c) Complete Description of Item.d) Unit of Item.e) Quantities of Item executed.f) Rate of Item (as per BOQ).g) Total Amount of Individual Item.h) Total Billed Amount.i) Standard Deduction, as applicable.

Simplex Concrete Piles (India) Limited 27

Bill No. and Date / Period :Name of the Contractor :Contractor Address :Name of the Work :Work Order / Agreement No. and Date :Original Contract Value :Executed Value of Contract :

ParticularsTotal Upto This Bill

Upto-Date Previous BillTotal Value of Work DoneSecured AdvanceRecoveries / Deductions

Secured AdvanceWork Tax @ …. %Income Tax @ …. %Education Cess Tax @ …. % of TDS AmountWater Charges @ …. %Recovery of Crane ChargesRecovery of Electricity ChargesRecovery against Penalty for Safety ViolationTotal Recoveries / Deductions

Net Amount Payable

Amount (In Rs)

PAYMENT CALCULATION SHEET

Item Decsription of Item Unit BOQ RateNo. Quantity In Rs Total Upto This Bill Total Upto This Bill

Upto-Date Previous Upto-Date PreviousBill Bill

Quantity Amount (In Rs)

ABSTRACT SHEET OF BILL

Purpose of BOQ

1. Tender Pricing– Common information with min. effort

2. Risk reduction by contractor – for rates entered in bill

3. Prompts customer to freeze project particulars

4. Basis for valuation of variations

5. Basis for ordering material &assessing labour requirement .

6. Useful for cost planning works in future contracts .

The Process (contd.)8. Billing

29

Principles and Procedure of Billing

While transferring the quantities from abstract to billthe total of quantities of the respective items shallbe ticked, so as to ensure that quantities of all itemsare transferred to bills.

30

9. METHOD OF MEASUREMENT OF WORKS – IN ACCORDANCE TO IS:1200

Each dimension shall be measured to nearest 0.01 mtr, where anydimension is more than 25 mtr it should be measured to the nearest 0.1mtr.

The measurement of earthwork shall be done in cubic metres, unlessotherwise mentioned.

‘Dead men’ or ‘tell-tales’ may be left at suitable intervals to determine theaverage depth of excavation, where the excavation is in trenches or fromborrow pits is being done in fairly uniform ground.

Where the ground is not uniform, levels shall be taken before the start,after site clearance and after the completion of the work and the quantityof excavation in cutting computed from these levels.

1. EARTHWORK1. EARTHWORK

31

EARTHWORK (contd.)

The materials to be excavated shall be classified as follows, unlessotherwise specified :

a) Soft / Loose Soil.b) Hard / Dense Soil.c) Mud.d) Soft / Disintegrated Rock.e) Hard Rock (Requiring Blasting).f) Hard Rock (Blasting Prohibited).

Where soft soil and hard rock are mixed, the measurement for the totalquantity shall be made. The hard rock excavated shall be stacked andmeasured in stack. The quantity of the hard rock excavated shall bearrived at by applying pre-accepted deductions for voids. From the totalquantity of the mixture, the quantity of hard rock excavated shall bededucted to work out the quantity of soft soil.

32

EARTHWORK (contd.)

In case of the following works, authorized quantities (calculated on thebasis of authorized working space) or those actually excavated,whichever are less, shall be measured :

a) in work which requires form work;b) in work which will be covered externally with a damp proof covering or

protective masonry work of brick, stone etc.;c) trenches which are to receive post tensioned concrete ground beams;d) special works like guniting etc.; Ande) In work which required workmen to operate from the outside.

33

EARTHWORK (contd.)

Authorized working space shall be specified in each case. Whereauthorized space is not so specified the following shall apply :o 60 cm measured from the face of structure (including protective

measures, if any) at lowest level. In addition for item “c” above the

extra length at each end shall be 1.50 mtr.

ACTUALEXCAVATIONLINE IN EXCAVATIONSLOPE PAY LINE

FOUNDATION

34

CONCRETE WORKS

Dimensions shall be measured to nearest 0.01 mtr except for thethickness of slab which shall be measured to nearest 0.005 mtr.

Unless otherwise stated all concrete work shall be measured in cubicmetres.

Unless otherwise stated formwork shall be measured separately.

Unless otherwise stated reinforcement shall be measured separately.

Columns shall be measured from top of column base to underside of firstfloor slab and subsequently from top of floor slab to underside of floorslab above.

35

CONCRETE WORKS (contd.)

Beam shall be measured from face to face of columns and shall includehaunches, if any, between columns and beams. The depth of beams shallbe measured from bottom of slab to bottom of the beam except in case ofinverted beam where it shall be measured from top of slab to top ofbeam.No deductions shall be made for the following :

a) Opening up to 0.1 m2 or as specified;

b) Volume occupied by reinforcement;

c) Volume occupied by pipes, conduits, sheathing etc. Not exceeding100 cm2 each in cross-sectional area or as specified;

36

FORMWORK

Formwork shall be measured in square metersas the actual surfaces in contact with theconcrete or any other material requiringformwork.

No deductions shall be made for opening upto 0.4 m2. No deduction shall be made for anyopening / cut-outs when slip form technique isused.

Formwork to secondary beams shall bemeasured up to the sides of main beams, butno deduction shall be made from the formworkof the main beam, where the secondary beamintersects it.

Formwork to beam shall be measured up tosides of column, but no deductions shall bemade from the formwork to stanchion orcolumn casings at intersections of beam.

37

STEEL REINFORCEMENT

Bar reinforcement shall be measured by weight in kilogram and shallinclude cutting to lengths, hooked ends, cranking or bending (straight orspiral). Authorized overlaps, chairs / separators shall be measured.When welding of joints is authorized it shall be described; Joints buttwelded shall be measured in numbers and lap welded shall be measuredin running metres of the length welded.Binding wire for fixing reinforcement shall not be measured, but shall beincluded in description of item.No deduction shall be made for opening not exceeding 1m2

38

BRICKWORK

Shall be measured in sqmBrickwork 1 brick thick (20 cm) or less shall be measured separately insqm

No deduction shall be made ifa) opening upto 0.1 sqm in areab) CC blocks for holdfast and holding down bolt

Deduction shall be made fora) Doors, Windows Openingb) Lintels or arches above doors/ openingc) Deduction for diff. shapes

-Cornice shall be measured in RM- Partition wall measured in sqm-Reinforced brickwork shall be measured in cum under separate item the

steel reinforcement shall be taken in tonnes.

AbstractingThe process by means of which the quantities of items of identical character and description arecollected from “take off sheets”, totaled and deduction made in order to arrive at the net totalquantities of respective items and in trade-wise order is called abstracting.

BillingIt is a claim for the amount of work done or supply. It consists of :-

a) Work Order or Agreement Number. b) Item Number.

c) Complete Description of Item. d) Unit of Item.

e) Quantities of Item executed. f) Rate of Item (as per BOQ).

g) Total Amount of Individual Item. h) Total Billed Amount.

i) Standard Deduction, as applicable.

10. DETAILED SPECIFICATION

• Specification -document attached with a tender form / contract agreement,• Controls the quality of materials and works.

– What it contains– Details on nature of work– Materials involved– Material specifications– Work procedure &Workmanship – Method of mixing / proportion

/method of laying /preparation of base or surface/ compaction/finishing &curing etc.

– Tolerance permitted for materials & work– Tools &plants– Method of measurement– Units for payment

– Purpose– Cost of unit quantity– Basis for Material Procurement schedule &Labour deployment , P&M

deployment &rate analysis– Contractual –Change in Specs lead to change in cost w.r.t Tendered

cost .– Acts as guide for supervising staff to execute work as per satisfaction– Basis for verifying &checking the strength of material for work involved in

project.– Useful for Arbitration &court cases

• Nature of work• Gives description of work in a detailed manner

signifying type /category of work.• At different levels places structures buildings

etc• Eg. Masonry in ..., plaster…., Flooring...,

Cladding... Etc for the material used.

DETAILED SPECIFICATIONS

• Materials involved• Lists out various materials which are used in work

specifying– Name,– Class or grade,– Type,– Category.

• Tolerances– Gives limit measured from true level /dimension up to which

material / workmanship could be accepted.– This is in reference to the provisions under standard I.S. Codes of

practice or other references as per contract.


• Material specificationGives physical and chemical composition of the material, it’sproperties according to relevant standards and also extent ofperformance required of material viz. Acceptable limits.

• Work procedureGives a detailed description of various steps involved inexecution of work including necessary pre-cautions asrequired.

• Method of measurement• Specifies mode of measurements for various kinds of

work.• This is based on the procedures given in contract

/standard I.S. Codes and others as the case may be.• METHOD OF PAYMENTS• Specifies procedures /rules governing terms of payments, stages

of payments, and modus - operandi for payments of various kindsof works.


11. RATE ANALYSIS

It is to determine the current rate per unit of an item at the locality.

PURPOSE OF RATE ANALYSIS

• To examine the Viability of Rates offered by / to Client /Contractor.

• To fix up the Agency / labor Contractor to do the job.

• To fix the Cost Targets towards labour, material, equipment &others heads and to measure the performance of Project inFinancial Terms.

What are the components in rate analysis ?

It can be classified under 3 major heads, they are :

• Direct Expenses,

• Indirect Expenses,

• Profit (on the above).

ANALYSIS OF RATES, USE OF COST DATA IN ESTIMATION

Estimation

Quantity Rate Amount

Material Labour Others Overhead,Profit &

Contingency

Equipment,Plant &Tools

Piece ratebasis

Supplybasis

AgencyCommission

Misc. Expenses

As perdrawing

Actual asper Site

Least of thetwo

or as perContractcondition

X =

Material

Ingradient A Ingradient B Ingradient C

Coefficient / Unit

Wastage as visualized / Unit

Requirement of Quantity / Unit

Rate / Unit

Basic rate + PackingForwarding Charges +

Taxes, Duties etc

Cost ofHire

Charges /Depreciation

Equipment

Duration of Deployment

Cost ofFoundation andMobilization &Demobilization

Cost ofMaintenance

& Spares

Cost ofOperator& Helper

Cost ofP.O.L.

Quantity / Unit

X

=

+

X

=

+

X

+

++

+

PURPOSE OF RATE ANALYSIS

Main purpose of rate analysis are the followings :-

a) To determine the current rate per unit of an item at the locality.

b) To examine the viability or rates offered by the contractors .

c) To calculate the quantity of materials and labour strength requiredfor project planning .

d) To fix up labour contract rates.

HOW TO FIX UP RATE PER UNIT OF AN ITEMS

The following sub-heads are estimated and a summation of these isthe rate per unit of an item

a) Quantity of materials and costs,

b) Labour costs,

c) Cost of equipments or tools and plant (T & P),

d) Contingencies,

e) Different heads of indirect Expenses to be considered inestimation,

f) Profit.

estimating &quantity surveying.pdf

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