Detailed Estimates of Buildings: Step-by-Step Guide

Introduction

A detailed estimate breaks the project into items (earthwork, concrete, brickwork, plastering, etc.), computes quantities for each, and multiplies by workable rates to get total cost.

It is prepared in two stages:

1. Details of measurements – Quantities
2. Abstract of estimated cost – Amounts

This guide walks through the process with a single-room building example.

Stage 1: Details of Measurements

Division of Work

Divide the work into items such as:

• Earthwork excavation
• CC bed for foundation
• RR masonry / brick masonry
• RCC (lintels, beams, slab)
• Sand filling, flooring
• Plastering, white washing, painting
• Doors, windows, fittings

Measurement Form

For each item, use columns:

S.No.	Description	No.	Length (m)	Breadth (m)	Depth/Height (m)	Quantity	Notes
1	Earthwork excavation	2	6.2	0.9	1.4	15.264	Long walls
		2	3.4	0.9	1.4	8.568	Short walls
	Total					24.192 cum

Quantity = No. × L × B × H

Use long wall–short wall or centre line methods as appropriate.

Deductions

For brickwork, deduct door and window openings:

• Opening volume = L × Wall thickness × H
• Also deduct lintel volume if included in wall
• Net brickwork = Gross − Deductions

Stage 2: Abstract of Estimated Cost

Abstract Format

Item No.	Description	Quantity	Unit	Rate (₹)	Amount (₹)
1	Earthwork excavation	24.192	cum	465/10 cum	1,125.00
2	CC (1:4:8) for foundation	5.184	cum	4,545/cum	23,561.28
...				Total

Rates come from rate analysis or standard schedule of rates.

Typical Items for Single-Room Building

1. Earthwork excavation
2. CC (1:4:8) bed for foundation
3. RR masonry in CM (1:6) for footings and basement
4. Sand filling in basement
5. Brick masonry in CM (1:6) for superstructure (net of openings)
6. RCC (1:2:4) for lintels, beams
7. RCC (1:2:4) for roof slab
8. CC (1:5:10) for flooring
9. Flooring (mosaic/tiles)
10. Doors, windows (supply and fixing)
11. Plastering with CM (1:6)
12. White washing / colour washing
13. Painting
14. Provision for water supply & sanitary @ 12.5%
15. Provision for electrification @ 7.5%
16. Provision for architectural appearance @ 2%
17. Provision for unforeseen items @ 2%
18. P.S. & contingencies @ 4%

Example Abstract (Single Room, Load Bearing)

Approximate costs (rates illustrative):

Item	Qty	Unit	Rate	Amount (₹)
Earthwork excavation	24.192	cum	465/10 cum	1,125
CC (1:4:8)	5.184	cum	4,545/cum	23,561
RR masonry CM (1:6)	10.94	cum	1,391/cum	15,218
Sand filling	8.96	cum	195/10 cum	175
Brick masonry CM (1:6)	18.03	cum	2,291/cum	41,307
RCC lintels/beams	1.984	cum	6,030/cum	11,964
RCC slab	3.09	cum	6,030/cum	18,633
CC flooring	1.86	cum	1,452/cum	2,701
Doors, windows, plastering, flooring, painting, etc.				~30,000
Subtotal				~1,64,000
Water supply @ 12.5%				20,500
Electrification @ 7.5%				12,300
Architectural @ 2%				3,280
Unforeseen @ 2%				3,280
P.S. & contingencies @ 4%				6,560
Grand Total				~2,10,000

Factors Affecting Detailed Estimate

1. Quantity and transport of materials – Bulk purchase and transport reduce cost.
2. Site location – Affects transport, damage, and storage.
3. Local labour – Skill, availability, and wages vary by region. Use current labour rates for your area.

What the Estimate Should Include

• Report – Brief description and assumptions
• Specifications – General and detailed
• Drawings – Plans, elevations, sections
• Design calculations – Where applicable
• Standard schedule of rates – Reference for rates

Petty Supervision and Contingencies

Usually 4% of the estimate is added for:

• Minor supervision
• Unforeseen items
• Rounding

This is separate from contractor profit, which may be added in tender or negotiated separately.

Data: Fixing Unit Rates

Data = Process of working out cost or rate per unit of each item.

• Material and labour quantities from Standard Data Book (SDB)
• Rates from current standard schedule of rates
• Lead statement for transport and conveyance

Rate per unit includes:

• Materials (first cost, freight, transport)
• Labour (number × wage per day)
• Equipment/T&P (1–2% of estimate)
• Overheads (4% of estimate)

Next Steps

• Rate Analysis – How to derive unit rates from materials and labour
• RCC & Steel Estimation – Reinforcement quantities and bar bending schedule