Types of Estimate

Methods of preparing an approximate estimate, and the suitability of each

Accuracy rises down the table and so does the effort. Methods 1–3 need only one overall figure; method 4 needs a preliminary layout. All of them are used before detailed drawings exist, which is exactly why none can be as accurate as a detailed estimate.

ENCE 351 §3.1.

Why an approximate estimate is made before the detailed estimate

1. At the proposal stage the detailed drawings and specifications do not yet exist, so a detailed estimate is simply impossible. Only an overall parameter — plinth area, cube content, number of beds — is known.
2. An approximate estimate is quick and cheap; a detailed estimate takes weeks of work. There is no sense in spending that effort on a scheme that may never be approved.
3. It allows the competent authority to decide whether the scheme is worth pursuing and to grant administrative approval, and allows the amount to be provided in the budget.
4. It allows alternative schemes, sites and designs to be compared on cost before one is selected for detailed design.
5. It fixes the order of magnitude, so the detailed estimate prepared later can be checked against it — a large discrepancy signals an error in one of them.
6. It lets the funding, land acquisition and clearances be started early, in parallel with the detailed design.

The relationship is one of successive refinement: rough cost → approximate estimate (administrative approval) → detailed estimate (technical sanction) → tendered cost → actual cost. Each stage narrows the band of uncertainty.

ENCE 351 §3.1.

a) Approximate estimate, and when a revised estimate is needed

Approximate estimate. A rough estimate of the probable cost of a work, prepared at the proposal stage before detailed drawings and specifications exist, from a single overall parameter such as the plinth area, the cube content or the number of service units. It is supported by a report, a site plan and line drawings.

It is prepared in order to:

• judge whether the scheme is financially feasible and worth pursuing at all;
• obtain administrative approval from the competent authority;
• provide the amount in the annual budget;
• compare alternative schemes and sites on cost before one is chosen; and
• fix the order of magnitude, against which the detailed estimate prepared later can be checked.

It is accurate to about ±15–20% only, and cannot be used for technical sanction or for inviting tenders.

Revised estimate. A fresh detailed estimate prepared for a work that has already been sanctioned. It is needed when:

1. the expenditure exceeds, or is likely to exceed, the sanctioned amount by more than 5%;
2. the rates adopted in the original estimate have changed materially;
3. there is a substantial change in the design, specification or scope of the work;
4. site conditions turn out to differ from those assumed — rock instead of soil, a high water table, a longer lead; or
5. the work was abandoned and is being restarted after a long interval.

It shows the original and the revised quantity and cost of every item side by side, with the reason for each variation, and must be sanctioned afresh by the competent authority before the extra expenditure is incurred.

b) Preliminary estimate of a six-storeyed framed office building

The carpet area printed in the question paper is not legible in the available copy. A total carpet area of 3000 m² is assumed below; substitute the figure given in your paper — the method is unchanged.

Convert carpet area to plinth area

Cost of the building by the plinth area method

Add the external services and other provisions

Two things carry the marks here: converting carpet area to plinth area (carpet area is the usable area only, and never equals the plinth area), and adding the external services as percentages. State every assumed percentage explicitly — an approximate estimate is only as good as its stated assumptions.

ENCE 351 §3.1 and §3.3.

a) Methods of quantity estimate

1. Long wall — short wall method
2. Centre line method
3. Crossing method
4. Bay method

b) Bill of quantities (BOQ)

A bill of quantities is a tabulated schedule of every item of work in a project, giving a brief description of the item, the estimated quantity, the unit, the rate and the amount. It is issued with the tender documents so that all contractors price the same quantities and their offers can be compared item by item; it is afterwards used to measure and pay for the work actually done and to value variations.

c) Preparation of a detailed estimate of a project

1. Collect the data — complete drawings, specifications, the district rate and the departmental norms.
2. List the items of work under sub-heads, in the order of construction.
3. Find the wall length by the centre line or long wall–short wall method.
4. Take out the quantities item by item on the measurement sheet (number × length × breadth × height), applying the deduction rules of IS 1200.
5. Analyse the rate of each item from the norms and the district rate.
6. Prepare the abstract of cost — quantity × rate = amount for every item, and total it.
7. Add contingencies (3–5%) and work-charged establishment (1.5–2%), and the provisions for sanitary, water supply and electrical work (8–10% each).
8. Write the report and attach the drawings, specifications, rate analysis and the abstract, and submit for technical sanction.

ENCE 351 Chapter 2, §3.2 and §3.7.

Components of a detailed estimate report for a road project, with their format

1. Title page, index and approval sheet.
2. Report — the need for the road, the traffic it will carry, the alignment chosen and the alternatives rejected, the design standard (road class, formation width, pavement type), the survey carried out and the basis of the rates.
3. Drawings — index map, alignment plan, longitudinal section showing ground and formation levels, typical and actual cross-sections at every chainage, and drawings of the cross-drainage and protection works.
4. Earthwork calculation sheet, chainage by chainage:

5. Detailed measurement sheets for the pavement layers, cross drainage structures, retaining and breast walls, side drains and road furniture.
6. Analysis of rates for every item, based on the district rate and the departmental norms, with a lead statement for each material from its quarry or market.
7. Detailed abstract of cost — item, quantity, unit, rate, amount.
8. Summary / general abstract under sub-heads:

9. Bill of quantities for tendering.
10. Specifications of every item, and the land acquisition and compensation statement.

What makes a road estimate report different from a building one is the longitudinal section and the chainage-wise earthwork sheet — a road has no plan of rooms to measure, so the L-section is the primary document.

ENCE 351 §3.2, §3.6 and §5.4.

a) Data required for a detailed estimate of an irrigation project

1. Topographical survey — contour plan of the command area, longitudinal section and cross-sections of the canal alignment.
2. Hydrological data — the discharge of the source river, its variation through the year, and the dependable flow.
3. Agricultural data — the culturable command area (CCA), the crops and their duty and delta, and hence the design discharge of the canal.
4. Soil investigation — the nature of the soil along the alignment, its permeability (which decides whether lining is needed) and its bearing capacity.
5. Canal design data — bed width, full supply depth, side slope, bed slope, freeboard and the type and thickness of lining.
6. Details of structures — head works, head regulator, cross regulators, falls, outlets, aqueducts, culverts and escapes.
7. Land acquisition details and compensation rates.
8. Rates — the district rate, the departmental norms, and the lead of each material from its quarry.
9. Environmental and social data — IEE/EIA requirement, resettlement.

b) Sub-heads to be included in the estimate report

ENCE 351 §3.2, §3.6 and §5.6.

Detailed estimate report for a small sewerage project

1. Report. The population to be served, the present method of disposal and its defects, the sewerage scheme proposed, the outfall and the treatment adopted, and the basis of the design and of the rates.

2. Design data

• Present and design population (design period usually 20–30 years).
• Water supply rate per head per day; sewage ≈ 80% of the water supplied.
• Peak factor, and the infiltration allowance.
• Design discharge, and hence the size and gradient of each sewer (self-cleansing velocity 0.6–0.8 m/s, maximum 3 m/s).

3. Drawings. Index map, layout of the sewer network with manhole numbers, longitudinal section of each sewer line showing ground level, invert level and depth, standard drawings of manholes, and drawings of the treatment unit and outfall.

4. Sub-heads and items of work

5. Measurement sheet — the trench is measured reach by reach between manholes:

6. Analysis of rates for every item, 7. Abstract of cost, 8. Summary of cost with contingencies (3–5%) and work-charged establishment (1.5–2%), and 9. Bill of quantities for tendering.

The dominant cost in a sewerage project is trench excavation, and it grows sharply with depth — so excavation must be measured in depth stages (0–1.5 m, 1.5–3.0 m, and so on), each with its own rate, and separately below the water table.

ENCE 351 §3.2 and §3.6.

a) Methods of taking out quantities of civil engineering works

Four methods are used to take out the quantities of a load-bearing masonry building. All of them must give the same total length of wall — that identity is the check on the work.

1. Long wall — short wall method (also called the out-to-out and in-to-in method)

• Walls running in one direction are taken as long walls and measured from centre to centre plus one breadth of the wall (out to out).
• Walls at right angles to them are taken as short walls and measured from centre to centre minus one breadth (in to in).
• The length changes for every footing, because the breadth changes.

Suitability: best when the walls of a building are of different thicknesses, or when the rooms are of different sizes, because each wall is dealt with on its own.

2. Centre line method

• The total centre-line length of all the walls is found once.
• It is multiplied by the breadth and the depth of each item in turn.
• For every junction where a wall meets another, half the breadth of the item is deducted, because that corner would otherwise be counted twice.

Suitability: the quickest method, and the one normally used when all the walls are of the same thickness and meet in simple T or L junctions. It becomes error-prone where junctions are many or irregular.

3. Crossing method

• The out-to-out length of the walls is taken in both directions.
• The corners, which have then been counted twice, are deducted — one breadth for each crossing.

Suitability: simple rectangular plans without internal cross walls; it becomes clumsy as soon as partitions are introduced.

4. Bay method

• A long building of repeating panels is divided into identical bays.
• One typical bay is worked out in full and multiplied by the number of bays.
• The two end bays are taken separately, since they carry the gable or end wall.

Suitability: long repetitive structures — barracks, sheds, godowns, factory buildings, and framed buildings with equal spans.

b) Factors considered during detailed estimation

1. Completeness and correctness of the drawings — every dimension needed must be available and consistent; the estimate can be no better than the drawing.
2. The specification of each item — the class of material and the mix decide both the quantity and the rate.
3. The standard method of measurement (IS 1200) — particularly the deduction rules, which decide whether an opening is deducted at all.
4. Prevailing rates of materials, labour and carriage at the site, and the district rate in force.
5. Site conditions — nature of soil, water table, ground slope, access, and the lead and lift involved.
6. Availability of materials, skilled labour, water and power locally, and the distance from which they must be brought.
7. Season and duration of the work, and the likely escalation over that period.
8. Method of construction and the plant proposed — manual or mechanised.
9. Provisions for contingencies (3–5%), work-charged establishment (1.5–2%), and the percentage allowances for sanitary, water supply and electrical work.
10. Overheads, profit and taxes applicable.

ENCE 351 Chapter 2 and §3.2.

Preparing a detailed estimate of a building

Step 1 — collect the data. Complete working drawings (plan, elevation, sections, details), the general and detailed specifications, the current district rate and the departmental rate-analysis norms.

Step 2 — list the items of work under sub-heads, in the order in which they are actually built: earthwork → concrete → masonry → damp proofing → wood work → steel work → roofing → flooring → finishing → services.

Step 3 — find the wall length by the centre line or long wall–short wall method. In a load-bearing building this single length drives almost every item.

Step 4 — take out the quantities on the measurement sheet, applying the deduction rules of IS 1200:

Step 5 — analyse the rate of each item from the norms (material, labour, plant) and the district rate, adding overheads and profit.

Step 6 — prepare the abstract of cost: quantity × rate = amount for every item, and total.

Step 7 — add the provisions: contingencies 3–5%, work-charged establishment 1.5–2%, water supply and sanitary 8–10%, electrification 8–10%.

Step 8 — write the report and submit the estimate with the drawings, specifications, detailed measurement sheets, rate analysis and abstract for technical sanction.

ENCE 351 §3.2.

Preparing a detailed estimate of a building

Step 1 — collect the data. Complete working drawings (plan, elevation, sections, details), the general and detailed specifications, the current district rate and the departmental rate-analysis norms.

Step 2 — list the items of work under sub-heads, in the order in which they are actually built: earthwork → concrete → masonry → damp proofing → wood work → steel work → roofing → flooring → finishing → services.

Step 3 — find the wall length by the centre line or long wall–short wall method. In a load-bearing building this single length drives almost every item.

Step 4 — take out the quantities on the measurement sheet, applying the deduction rules of IS 1200:

Step 5 — analyse the rate of each item from the norms (material, labour, plant) and the district rate, adding overheads and profit.

Step 6 — prepare the abstract of cost: quantity × rate = amount for every item, and total.

Step 7 — add the provisions: contingencies 3–5%, work-charged establishment 1.5–2%, water supply and sanitary 8–10%, electrification 8–10%.

Step 8 — write the report and submit the estimate with the drawings, specifications, detailed measurement sheets, rate analysis and abstract for technical sanction.

ENCE 351 §3.2.

Preparing a detailed estimate of a building

Step 1 — collect the data. Complete working drawings (plan, elevation, sections, details), the general and detailed specifications, the current district rate and the departmental rate-analysis norms.

Step 2 — list the items of work under sub-heads, in the order in which they are actually built: earthwork → concrete → masonry → damp proofing → wood work → steel work → roofing → flooring → finishing → services.

Step 3 — find the wall length by the centre line or long wall–short wall method. In a load-bearing building this single length drives almost every item.

Step 4 — take out the quantities on the measurement sheet, applying the deduction rules of IS 1200:

Step 5 — analyse the rate of each item from the norms (material, labour, plant) and the district rate, adding overheads and profit.

Step 6 — prepare the abstract of cost: quantity × rate = amount for every item, and total.

Step 7 — add the provisions: contingencies 3–5%, work-charged establishment 1.5–2%, water supply and sanitary 8–10%, electrification 8–10%.

Step 8 — write the report and submit the estimate with the drawings, specifications, detailed measurement sheets, rate analysis and abstract for technical sanction.

ENCE 351 §3.2.

a) Points to be considered while measuring earthwork

1. Classification of the soil — soft/ordinary soil, hard soil, soft rock and hard rock requiring blasting are measured and paid separately, because the effort differs greatly.
2. Lead — the horizontal distance the excavated earth is carried. The first 30 m is normally included in the rate; beyond that, extra lead is paid in stages.
3. Lift — the vertical height through which the earth is lifted. The first 1.5 m is included in the rate; each additional 1.5 m is paid extra.
4. Depth of excavation, measured from the existing ground level, and taken in stages where the depth is large.
5. Dewatering — excavation below the water table or in slush is measured separately.
6. Working space and side slopes — measure the authorised dimensions of the trench as per drawing; extra excavation for the convenience of the contractor is not paid.
7. Excavation and filling kept separate, and the volume of filling measured after compaction, not loose.
8. Bulking and shrinkage — earth increases in volume when loosened and reduces when compacted, so the state in which the measurement is taken must be stated.
9. Unit — measured in m³ and generally paid per 100 m³. Surface dressing up to 30 cm deep is measured in m².

b) When a revised estimate is required

A revised estimate is a fresh detailed estimate prepared for a work already sanctioned. It becomes necessary when:

1. the expenditure exceeds, or is likely to exceed, the sanctioned amount by more than 5%;
2. the rates adopted in the original estimate have changed materially;
3. there is a substantial change in the design, specification or scope;
4. site conditions turn out to differ from those assumed; or
5. the work has been abandoned and is restarted after a long interval.

Example. A rural road was sanctioned for Rs. 2.00 crore on the assumption of ordinary soil throughout. On excavation, hard rock was met over 600 m of the alignment, raising the excavation cost and requiring additional breast walls. The anticipated cost rose to Rs. 2.35 crore — an excess of 17.5%, far beyond 5% — so a revised estimate was prepared showing the original and revised quantity and cost of each item side by side, with the reason for every variation, and was submitted for fresh sanction.

ENCE 351 §1.4 and §3.3.

a) Why a revised estimate should be prepared

Revised estimate. A fresh detailed estimate prepared for a work that has already been sanctioned. It is needed when:

1. the expenditure exceeds, or is likely to exceed, the sanctioned amount by more than 5%;
2. the rates adopted in the original estimate have changed materially;
3. there is a substantial change in the design, specification or scope of the work;
4. site conditions turn out to differ from those assumed — rock instead of soil, a high water table, a longer lead; or
5. the work was abandoned and is being restarted after a long interval.

It shows the original and the revised quantity and cost of every item side by side, with the reason for each variation, and must be sanctioned afresh by the competent authority before the extra expenditure is incurred.

It must be prepared because public money can be spent only up to the amount sanctioned. Once that limit is likely to be crossed, further expenditure is irregular until fresh sanction is obtained; the revised estimate is the document that seeks it, and it also serves to explain and record why the cost rose.

b) Rate analysis

Analysis of rates is the process of working out the cost of one unit of an item of work — per m³, per m², per m — by adding up the cost of the materials, the labour, the plant and the overheads that go into that unit, together with the contractor's profit.

c) Importance of rate analysis

1. It gives the correct rate of each item, and hence a realistic estimate; without it the estimate is only a guess.
2. It shows the quantity of each material and each class of labour required, so they can be procured and programmed.
3. It lets the department examine a contractor's quoted rate and judge whether it is reasonable, abnormally high or unworkably low.
4. It is the basis for fixing the rate of extra, substituted and non-scheduled items that arise during execution.
5. It shows the effect of a change in specification — how much the rate rises if the mix is made richer — and so helps in choosing between alternatives.
6. It allows the estimate to be updated when material or labour rates change, without re-doing the quantities.
7. It is required for settling claims, escalation and disputes.

ENCE 351 §3.3 and §6.1.

a) Components of a complete estimate

A complete estimate is one that covers every cost needed to bring the work into use — not merely the cost of the structure itself. Its components are:

1. Cost of land — purchase or acquisition, compensation, and the legal and registration charges.
2. Cost of the main work — the detailed estimate of the building or structure itself.
3. Water supply and sanitary installation — 8–10% of the building cost.
4. Internal electrical installation — 8–10%.
5. External services — approach road, paving, compound wall and gate, external water, sewer and electric connections, street lighting.
6. Architectural treatment and landscaping — 1–2% each.
7. Furniture and fixtures — 2–5%.
8. Special installations — lift, fire fighting, air conditioning, generator, where required.
9. Contingencies — 3–5%.
10. Work-charged establishment — 1.5–2%.
11. Supervision / engineering and consultancy fees.
12. Taxes as applicable (VAT 13%).

The point of a complete estimate is that a building is useless without water, drainage, power and access. An estimate that stops at the structure understates the true cost by roughly a quarter.

b) Sample abstract of cost

ENCE 351 §3.5 and §3.7.

a) Sub-heads of the various items of work

The items of an estimate are grouped under sub-heads, taken in the order in which the work is actually built. For a building project:

1. Earthwork — site clearance, excavation in foundation, refilling, plinth filling, disposal of surplus earth.
2. Concrete work — PCC in foundation and floors; RCC in footings, columns, beams, slabs, lintels and stairs, with formwork and reinforcement.
3. Masonry — brick or stone masonry in foundation, plinth and superstructure; partition walls.
4. Damp proofing — DPC at plinth level; waterproofing of roof and wet areas.
5. Wood work and joinery — door and window frames and shutters, with fittings and fastenings.
6. Steel work — grills, gates, rolling shutters, structural steel.
7. Roofing — roof slab or truss and covering, gutters and rain-water pipes.
8. Flooring — base concrete, floor finish, skirting and dado.
9. Finishing — plastering, pointing, white washing, distempering, painting.
10. Water supply and sanitary installation — 8–10% of building cost.
11. Electrical installation — 8–10%.
12. Miscellaneous and external works — compound wall, gate, approach road, paving, landscaping.

b) When an approximate estimate is prepared

An approximate estimate is prepared at the proposal stage, before detailed drawings and specifications exist — that is:

• when a scheme is first conceived and its financial feasibility must be judged;
• to obtain administrative approval of the competent authority;
• to provide the amount in the annual budget;
• to compare alternative schemes, sites or designs on cost; and
• to fix the order of magnitude against which the later detailed estimate can be checked.

ENCE 351 §3.1 and §3.6.

a) Various methods of taking out quantities

Four methods are used to take out the quantities of a load-bearing masonry building. All of them must give the same total length of wall — that identity is the check on the work.

1. Long wall — short wall method (also called the out-to-out and in-to-in method)

• Walls running in one direction are taken as long walls and measured from centre to centre plus one breadth of the wall (out to out).
• Walls at right angles to them are taken as short walls and measured from centre to centre minus one breadth (in to in).
• The length changes for every footing, because the breadth changes.

Suitability: best when the walls of a building are of different thicknesses, or when the rooms are of different sizes, because each wall is dealt with on its own.

2. Centre line method

• The total centre-line length of all the walls is found once.
• It is multiplied by the breadth and the depth of each item in turn.
• For every junction where a wall meets another, half the breadth of the item is deducted, because that corner would otherwise be counted twice.

Suitability: the quickest method, and the one normally used when all the walls are of the same thickness and meet in simple T or L junctions. It becomes error-prone where junctions are many or irregular.

3. Crossing method

• The out-to-out length of the walls is taken in both directions.
• The corners, which have then been counted twice, are deducted — one breadth for each crossing.

Suitability: simple rectangular plans without internal cross walls; it becomes clumsy as soon as partitions are introduced.

4. Bay method

• A long building of repeating panels is divided into identical bays.
• One typical bay is worked out in full and multiplied by the number of bays.
• The two end bays are taken separately, since they carry the gable or end wall.

Suitability: long repetitive structures — barracks, sheds, godowns, factory buildings, and framed buildings with equal spans.

b) Sub-heads of items of work for a building project

Sub-heads of items of work for a building project

The items of a building estimate are grouped under sub-heads, taken in the order in which the work is actually built:

1. Earthwork — site clearance, excavation in foundation, refilling, plinth filling, disposal of surplus earth.
2. Concrete work — PCC in foundation and floors, RCC in footings, columns, beams, slabs, lintels and stairs, with formwork and reinforcement.
3. Masonry / brickwork — brick or stone masonry in foundation, plinth and superstructure, partition walls.
4. Damp proofing — DPC at plinth level, waterproofing of roof and wet areas.
5. Wood work / joinery — door and window frames and shutters, cupboards, railings, with fittings and fastenings.
6. Steel work — grills, gates, rolling shutters, structural steel.
7. Roofing — roof slab or truss and covering, gutters, rain-water pipes.
8. Flooring — base concrete, floor finish, skirting and dado.
9. Finishing — internal and external plastering, pointing, white washing, distempering and painting.
10. Sanitary and water supply installation — fittings, pipes, septic tank and soak pit — usually 8–10% of the building cost.
11. Electrical installation — internal wiring, fittings and fixtures — usually 8–10%.
12. Miscellaneous and external works — compound wall, gate, approach road, paving, landscaping.

Grouping under sub-heads is not decoration. It makes the estimate easy to check, lets the work be split into separate contracts, and allows the departmental percentages for sanitary and electrical work to be applied to the right base.

ENCE 351 Chapter 2 and §3.6.

Project estimate for a water supply project

1. Design basis

2. Sub-heads and items of work

3. Summary of cost

4. Report and drawings — the report giving the source, the design population and demand, the scheme adopted and the per-capita cost; drawings comprising the index map, the layout of the system with the hydraulic gradient line, and standard drawings of the intake, reservoir and tap stand.

The report itself is written under these sub-heads:

1. Introduction, with the location of the project
2. Condition of the existing water supply
3. Need for the present project
4. Design data
5. Population projection
6. Water demand
7. Source of supply and the intake work
8. The scheme proposed, with alternatives considered
9. General abstract of cost, and the abstract cost of each sub-head
10. Schedule of rates, drawings and the land acquisition statement

The figure the evaluating authority actually looks at is the cost per capita — total project cost divided by the design population. Always state it.

ENCE 351 §3.6; report structure after Pandey & Katwal, Complete Manual ch.5 §5.8.

Project. A project is a temporary, non-repetitive undertaking taken up to create a unique product or facility, having a definite beginning and a definite end, its own objective, its own budget and its own team.

Characteristics of a project

1. Unique — no two projects are identical, even of the same design, because the site, time and people differ.
2. Temporary — it has a definite start and finish; the organisation is disbanded at the end.
3. Definite objective — a stated scope, quality, time and cost.
4. Progressive elaboration — the detail is developed in steps as the work proceeds.
5. Multi-disciplinary — it needs several trades and specialists working together.
6. Resource constrained — limited money, time, labour and plant.
7. Involves risk and uncertainty, which is why contingencies are provided.
8. Life cycle — conception, planning, execution, commissioning, closure.

Stages of a project estimate

1. Identification / conception. The need is established and the broad scope fixed. A rough cost estimate is made from a per-unit figure.
2. Pre-feasibility and feasibility. Alternatives, sites and technologies are compared. An approximate / preliminary estimate is prepared by the plinth area, cube content or service-unit method, and administrative approval is obtained on it.
3. Preliminary design. Line drawings and outline specifications are made; the estimate is refined by the approximate quantity method.
4. Detailed design. Complete working drawings and detailed specifications are prepared, and a full detailed estimate with rate analysis and abstract of cost is made. Technical sanction is obtained on this.
5. Tender stage. The bill of quantities is issued; the estimate is compared with the rates actually quoted, and the tender premium is assessed.
6. Execution. Running bills are checked against measured work; variations are valued; a revised or supplementary estimate is prepared if the cost exceeds the sanction by more than 5% or the scope changes.
7. Completion. The final bill and the completion report are prepared, comparing the actual cost with the sanctioned estimate and explaining the difference.

ENCE 351 §3.6.

a) Stages of a project estimate

Stages of a project estimate

1. Identification / conception. The need is established and the broad scope fixed. A rough cost estimate is made from a per-unit figure.
2. Pre-feasibility and feasibility. Alternatives, sites and technologies are compared. An approximate / preliminary estimate is prepared by the plinth area, cube content or service-unit method, and administrative approval is obtained on it.
3. Preliminary design. Line drawings and outline specifications are made; the estimate is refined by the approximate quantity method.
4. Detailed design. Complete working drawings and detailed specifications are prepared, and a full detailed estimate with rate analysis and abstract of cost is made. Technical sanction is obtained on this.
5. Tender stage. The bill of quantities is issued; the estimate is compared with the rates actually quoted, and the tender premium is assessed.
6. Execution. Running bills are checked against measured work; variations are valued; a revised or supplementary estimate is prepared if the cost exceeds the sanction by more than 5% or the scope changes.
7. Completion. The final bill and the completion report are prepared, comparing the actual cost with the sanctioned estimate and explaining the difference.

b) Characteristics of technical report writing for a project

1. Accuracy — every figure, quantity and rate must be correct and traceable to its source; a technical report is a record, not an opinion.
2. Clarity and simplicity — short sentences, plain language, no ambiguity. It will be read by administrators as well as engineers.
3. Objectivity — conclusions must follow from the data presented, not from the writer's preference; alternatives rejected must be stated with reasons.
4. Completeness — all the data needed to check the conclusion must be included, with nothing material omitted.
5. Logical order — introduction → need for the work → investigation and data → alternatives → the scheme adopted → design → estimate → conclusion and recommendation.
6. Supported by drawings, tables and charts, each numbered, titled and referred to in the text.
7. Standard units and notation throughout (SI), with sources of all rates quoted.
8. Brevity — supporting calculations go into appendices, not the main body.
9. Proper structure — title page, summary, index, main body, conclusions and recommendations, references, appendices.
10. Signed and dated, with the responsibility of the writer clearly recorded.

ENCE 351 §3.6.

a) Requisites for a project estimate

1. Complete drawings — site plan, layout, plans, elevations, sections and detail drawings, all fully dimensioned and to scale.
2. Detailed specifications of every item of work.
3. Survey and investigation data — topographic survey, soil investigation, water table, and for a road or canal the longitudinal section.
4. Schedule of rates — the current district rate of materials, labour and carriage.
5. Rate-analysis norms of the department.
6. Standard method of measurement (IS 1200 or departmental rules).
7. Lead statement for every material from its source.
8. Land acquisition details and compensation rates.
9. Provisions for contingencies, work-charged establishment, services and taxes.
10. Report justifying the work, and the approval of the competent authority.

b) Factors considered while preparing a building project estimate

1. Type and use of the building — residential, office, hospital, school — which fixes the standard of finish and the services required.
2. Number of storeys and the structural system — load bearing or framed; a framed building shifts the cost from masonry to RCC and steel.
3. Site conditions — soil and bearing capacity, water table, slope, and access for materials and plant.
4. Specification and quality of materials and finishes adopted.
5. Local rates of materials and labour, and the lead from which each material must be brought.
6. Availability of skilled labour, water and power at the site.
7. Season and duration of construction, and the likely escalation.
8. Services — water supply and sanitary 8–10%, electrification 8–10%, and any lift or fire fighting installation.
9. External development — compound wall, gate, approach road, landscaping.
10. Statutory requirements — building by-laws, setback, height limit, seismic code, municipal approval fees.
11. Contingencies, establishment, overheads, profit and taxes.

ENCE 351 §3.6.

a) Tasks in preparing the estimate of a building project

1. Study the drawings and specifications thoroughly, and clear every ambiguity with the designer before starting.
2. Visit the site and record the soil, water table, ground slope, access and the lead of each material.
3. List the items of work under sub-heads in the order of construction.
4. Find the wall length by the centre line or long wall–short wall method.
5. Take out the quantities item by item on the measurement sheet, applying the IS 1200 deduction rules.
6. Prepare the bar bending schedule and convert the reinforcement to weight at w = d²/162 kg/m.
7. Collect the rates — district rate, market rates, carriage — and analyse the rate of every item from the departmental norms.
8. Prepare the abstract of cost and total it.
9. Add the provisions — services, contingencies, establishment, taxes.
10. Check the estimate against an approximate plinth-area figure, to catch gross errors.
11. Write the report, prepare the bill of quantities, and submit for technical sanction.

b) Estimate of an irrigation project

An irrigation project is estimated in the same way, but the quantities are driven by the design discharge rather than by a plan of rooms.

Design basis: from the culturable command area and the duty of the crops, the design discharge Q is found; the canal section (bed width B, full supply depth D, side slope s, bed slope) follows from it.

Sub-heads: preliminary works · land acquisition and compensation · head works (diversion weir, intake, head regulator, river training) · main canal earthwork in cutting and filling · dressing and trimming · lining · branch canals and distributaries · canal structures (cross regulators, falls, outlets, aqueducts, culverts, escapes) · drainage works · inspection road · buildings · environmental mitigation · contingencies and establishment.

Presentation: the earthwork is set out chainage by chainage with cutting and filling in separate columns, so that the balance of earthwork — and hence the borrow or spoil — is visible; each structure is estimated separately and brought into the abstract as a lump item.

ENCE 351 §3.6 and §5.6.

Project. A project is a temporary, non-repetitive undertaking taken up to create a unique product or facility, having a definite beginning and a definite end, its own objective, its own budget and its own team.

Characteristics of a project

1. Unique — no two projects are identical, even of the same design, because the site, time and people differ.
2. Temporary — it has a definite start and finish; the organisation is disbanded at the end.
3. Definite objective — a stated scope, quality, time and cost.
4. Progressive elaboration — the detail is developed in steps as the work proceeds.
5. Multi-disciplinary — it needs several trades and specialists working together.
6. Resource constrained — limited money, time, labour and plant.
7. Involves risk and uncertainty, which is why contingencies are provided.
8. Life cycle — conception, planning, execution, commissioning, closure.

How a building project is estimated

Preparing a detailed estimate of a building

Step 1 — collect the data. Complete working drawings (plan, elevation, sections, details), the general and detailed specifications, the current district rate and the departmental rate-analysis norms.

Step 2 — list the items of work under sub-heads, in the order in which they are actually built: earthwork → concrete → masonry → damp proofing → wood work → steel work → roofing → flooring → finishing → services.

Step 3 — find the wall length by the centre line or long wall–short wall method. In a load-bearing building this single length drives almost every item.

Step 4 — take out the quantities on the measurement sheet, applying the deduction rules of IS 1200:

Step 5 — analyse the rate of each item from the norms (material, labour, plant) and the district rate, adding overheads and profit.

Step 6 — prepare the abstract of cost: quantity × rate = amount for every item, and total.

Step 7 — add the provisions: contingencies 3–5%, work-charged establishment 1.5–2%, water supply and sanitary 8–10%, electrification 8–10%.

Step 8 — write the report and submit the estimate with the drawings, specifications, detailed measurement sheets, rate analysis and abstract for technical sanction.

To the total so obtained are added the project-level provisions that turn a building estimate into a project estimate: land, water supply and sanitary installation (8–10%), electrification (8–10%), external development, furniture, contingencies (3–5%), work-charged establishment (1.5–2%), consultancy fees and taxes.

ENCE 351 §3.2 and §3.6.

Project. A project is a temporary, non-repetitive undertaking taken up to create a unique product or facility, having a definite beginning and a definite end, its own objective, its own budget and its own team.

Characteristics of a project

1. Unique — no two projects are identical, even of the same design, because the site, time and people differ.
2. Temporary — it has a definite start and finish; the organisation is disbanded at the end.
3. Definite objective — a stated scope, quality, time and cost.
4. Progressive elaboration — the detail is developed in steps as the work proceeds.
5. Multi-disciplinary — it needs several trades and specialists working together.
6. Resource constrained — limited money, time, labour and plant.
7. Involves risk and uncertainty, which is why contingencies are provided.
8. Life cycle — conception, planning, execution, commissioning, closure.

Estimate of an irrigation project

Data required: topographic survey and contour plan of the command area; longitudinal section and cross-sections of the alignment; hydrological data of the source; the culturable command area, crops, duty and delta — from which the design discharge follows; soil investigation along the alignment; and the district rate and norms.

Design of the section:

Sub-heads of the estimate:

1. Preliminary works — survey, investigation, design and drawing.
2. Land acquisition and compensation.
3. Head works — diversion weir or intake, head regulator, silt excluder, river training.
4. Main canal — clearing, earthwork in cutting and in embankment (kept in separate columns), dressing and trimming, lining.
5. Branch canals, distributaries and water courses.
6. Canal structures — cross regulators, falls, outlets, aqueducts, syphons, culverts, escapes, bridges.
7. Drainage works.
8. Inspection road along the bank.
9. Buildings — office, store, quarters, gauge stations.
10. Miscellaneous — turfing, plantation, boundary pillars, measuring devices.
11. Environmental mitigation as per the IEE / EIA.
12. Contingencies 3–5% and work-charged establishment 1.5–2%.

Presentation: the earthwork sheet runs chainage by chainage with cutting and filling totalled separately, so the balance of earthwork is visible; each structure is estimated on its own and carried into the abstract as one item. The report should state the cost per hectare of command area, which is the figure used to judge the project.

ENCE 351 §3.6 and §5.6.

a) Project estimate

A project estimate is the estimate of the whole project — not merely of the main structure — covering every component and every ancillary cost needed to bring the facility into use: land, the main work, all its sub-works, external services, contingencies, establishment, fees and taxes. It is the document on which the project is sanctioned and budgeted.

b) How a project estimate is prepared

1. Define the scope and break the project into its components (work breakdown structure).
2. Collect the data — drawings, specifications, survey and soil data, district rate, norms, lead statement.
3. Estimate each component separately — take out the quantities, analyse the rates, and abstract the cost of each.
4. Group the components under sub-heads and prepare the general abstract.
5. Add the project-level provisions — land, services (8–10% each), external development, contingencies (3–5%), work-charged establishment (1.5–2%), consultancy fees and taxes (13% VAT).
6. Prepare the summary of cost and the bill of quantities.
7. Write the report and submit for administrative approval and technical sanction.

c) Reports on an estimate

ENCE 351 §3.6.

Project. A project is a temporary, non-repetitive undertaking taken up to create a unique product or facility, having a definite beginning and a definite end, its own objective, its own budget and its own team.

Characteristics of a project

1. Unique — no two projects are identical, even of the same design, because the site, time and people differ.
2. Temporary — it has a definite start and finish; the organisation is disbanded at the end.
3. Definite objective — a stated scope, quality, time and cost.
4. Progressive elaboration — the detail is developed in steps as the work proceeds.
5. Multi-disciplinary — it needs several trades and specialists working together.
6. Resource constrained — limited money, time, labour and plant.
7. Involves risk and uncertainty, which is why contingencies are provided.
8. Life cycle — conception, planning, execution, commissioning, closure.

Estimation of a road project

Data required: traffic survey and the design traffic; topographic survey of the alignment with the longitudinal section and cross-sections at every chainage; soil investigation and CBR of the subgrade; the design standard (road class, formation width, camber, gradient); quarry locations and the lead of each material; and the district rate and norms.

Earthwork — the governing item:

Sub-heads of the estimate:

1. Preliminary works — survey, investigation, design and drawing.
2. Land acquisition and compensation.
3. Site clearance — clearing and grubbing, removal of structures.
4. Earthwork — excavation in cutting by soil class, embankment in compacted layers, disposal of surplus.
5. Pavement — subgrade preparation (m²), granular sub-base, base course, prime and tack coat, bituminous surfacing, seal coat, shoulders.
6. Cross drainage — pipe, slab and box culverts, causeways, bridges.
7. Protection works — retaining, breast and toe walls, gabions, slope protection.
8. Drainage — side drains, catch drains, cross drains.
9. Road furniture — signs, markings, guard posts, kilometre stones, parapets.
10. Bio-engineering and plantation.
11. Miscellaneous — diversion road, traffic management during construction.
12. Contingencies 3–5% and work-charged establishment 1.5–2%.

Presentation: the estimate is built on the chainage-wise earthwork sheet and the pavement quantities per km. The report should state the cost per kilometre, which is the figure used to compare road projects.

ENCE 351 §3.6, §5.4 and §5.5.

Project. A project is a temporary, non-repetitive undertaking taken up to create a unique product or facility, having a definite beginning and a definite end, its own objective, its own budget and its own team.

Characteristics of a project

1. Unique — no two projects are identical, even of the same design, because the site, time and people differ.
2. Temporary — it has a definite start and finish; the organisation is disbanded at the end.
3. Definite objective — a stated scope, quality, time and cost.
4. Progressive elaboration — the detail is developed in steps as the work proceeds.
5. Multi-disciplinary — it needs several trades and specialists working together.
6. Resource constrained — limited money, time, labour and plant.
7. Involves risk and uncertainty, which is why contingencies are provided.
8. Life cycle — conception, planning, execution, commissioning, closure.

Estimate of an irrigation project

Data required: topographic survey and contour plan of the command area; longitudinal section and cross-sections of the alignment; hydrological data of the source; the culturable command area, crops, duty and delta — from which the design discharge follows; soil investigation along the alignment; and the district rate and norms.

Design of the section:

Sub-heads of the estimate:

1. Preliminary works — survey, investigation, design and drawing.
2. Land acquisition and compensation.
3. Head works — diversion weir or intake, head regulator, silt excluder, river training.
4. Main canal — clearing, earthwork in cutting and in embankment (kept in separate columns), dressing and trimming, lining.
5. Branch canals, distributaries and water courses.
6. Canal structures — cross regulators, falls, outlets, aqueducts, syphons, culverts, escapes, bridges.
7. Drainage works.
8. Inspection road along the bank.
9. Buildings — office, store, quarters, gauge stations.
10. Miscellaneous — turfing, plantation, boundary pillars, measuring devices.
11. Environmental mitigation as per the IEE / EIA.
12. Contingencies 3–5% and work-charged establishment 1.5–2%.

Presentation: the earthwork sheet runs chainage by chainage with cutting and filling totalled separately, so the balance of earthwork is visible; each structure is estimated on its own and carried into the abstract as one item. The report should state the cost per hectare of command area, which is the figure used to judge the project.

ENCE 351 §3.6 and §5.6.

Works an estimator must take into account in a project estimate

An estimator who prices only the visible structure will always under-estimate. The following heads must all be accounted for.

1. Preliminary works — survey, soil investigation, testing, design and drawing, and the preparation of the estimate itself.
2. Land — purchase or acquisition, compensation for crops and structures, legal and registration charges.
3. Site works — clearing and grubbing, demolition of existing structures, site levelling, temporary access, site office, store, water and power connection, fencing and security.
4. The main work — the structure itself, item by item under its sub-heads.
5. Sub-works and ancillary structures — boundary wall, gate, guard room, septic tank and soak pit, overhead and underground tanks, generator room, pump house.
6. Internal services — water supply and sanitary installation (8–10%), electrification (8–10%), and any lift, fire fighting or air conditioning installation.
7. External services — approach road, paving, drainage, street lighting, and the external water, sewer and electric connections.
8. Landscaping — lawns, plantation, and any architectural treatment.
9. Furniture, fixtures and equipment needed to make the facility usable.
10. Environmental and social mitigation as required by the IEE or EIA, and resettlement where applicable.
11. Establishment and supervision — work-charged establishment (1.5–2%), consultancy and supervision fees.
12. Contingencies (3–5%) for unforeseen petty expenses.
13. Escalation over the construction period, and taxes (VAT 13%) and duties.
14. Maintenance during the defect liability period, where it is at the employer's cost.

Together the internal and external services alone add roughly 20–25% to the bare cost of a building. Omitting them is the single commonest cause of a project estimate falling short.

ENCE 351 §3.5 and §3.6.

The quantity and rate columns are not fully legible in the available copy of this question paper — only the PCC rate of Rs 9,000 per m³ survives. Representative quantities and rates are assumed below and are marked as such; substitute the figures printed in your paper. The method, the order of the three statements and the treatment of the 5% contingency and 13% tax are what carry the marks.

Bill of Quantities (BOQ)

The BOQ lists the items with their quantities and units, for the contractor to price. The rate and amount columns are left blank in the tender copy.

Abstract of Cost (AOC)

The same items, now priced: amount = quantity × rate.

Summary of cost, with contingency and tax

The order matters and is the point of the question: tax is charged on the cost including contingency, not on the bare cost of works. Taking 13% of 14,15,000 instead would give Rs 1,83,950 and a wrong total. Note also the difference between the three statements — the BOQ is the unpriced schedule issued to tenderers, the AOC is the priced statement of the items, and the summary adds the overheads to give the project cost.

ENCE 351 §3.7.