Intermediate Vocational Course, 2nd Year : ESTIMATING & CONSTING (FOR THE COURSE OF CONSTRUCTION TECHNOLOGY) Authors : B.N. Suresh, Editor : B. Harnath Reddy, First Edition : 2006 State Institute of Vocational Education Andhra Pradesh, Hyderabad. Printed and Published by the Telugu Akademi, Hyderabad on behalf of the State Institution of Vocational Education Directorate of Intermediate Education Govt. of Andhra Pradesh, Hyderabad. First Edition : 2006 Copies : . All rights whatsoever in this book are strictly reserved and no portion of it may be reproduced by any process for any purpose without the written permission of the copyright owners. Price : Rs. /- Printed in India Laser Typeset Reformatted by Chinmai D.T.P. Works, Chittor TExt Printed at ........................................ Andhra Pradesh. AUTHOR B.N. SURESH B.E. J.L. in Construction Technology (Vocational) Govt. Junior College for Girls Guntur. EDITOR B. HARNATH REDDY B.Tech. J.L. in Construction Technology (Vocational) New Govt. Junior College Malakpet, Hyderabad. INDEX S.No. Topic Page No. 01. Introduction to the subject 1 - 3 02. Measurement of Materials & Works 4 - 12 03. Types of Estimates 13 - 21 04. Detail & Abstract Estimates of Buildings 22 - 55 05. Analysis of Rates 56 - 73 06. Estimation of Quantities of Steel & RCC Elements 74 - 80 07. Earth Work Calculations 81 - 95 08. Detailed Estimates 96 - 108 09. Appendex 109 - 115 1 Estimation and Costing INTRODUCTION TO THE SUBJECT 1.1 DEFINITION OF ESTIMATING AND COSTING Estimating is the technique of calculating or Computing the various quantities and the expected Expenditure to be incurred on a particular work or project. In case the funds avilable are less than the estimated cost the work is done in part or by reducing it or specifications are altered, the following require- ment are necessary for preparing an estimate. a ) Drawings like plan, elevation and sections of important points. b) Detailed specifications about workmenship & properties of materials etc. c) Standard schedule of rates of the current year. 1.2 NEED FOR ESTIMATION AND COSTING 1. Estimate give an idea of the cost of the work and hence its feasibility can be determined i..e whether the project could be taken up with in the funds available or not. 2. Estimate gives an idea of time required for the completion of the work. 3. Estimate is required to invite the tenders and Quotations and to arange contract. 4. Estimate is also required to control the expenditure during the execution of work. 5. Estimate decides whether the proposed plan matches the funds available or not. 1.3 PROCEDURE OF ESTIMATING OR METHOD OF ESTIMATING. Estimating involves the following operations 1. Preparing detailed Estimate. 2. Calculating the rate of each unit of work 3. Preparing abstract of estimate 1.4 DATA REQUIRED TO PREPARE AN ESTIMATE 1. Drawings i.e.plans, elevations, sections etc. 2. Specifications. 3. Rates. Chapter 1 2 1.4.1 DRAWINGS If the drawings are not clear and without complete dimensions the prepa- ration of estimation become very difficult. So, It is very essential before prepar- ing an estimate. 1.4.2. SPECIFICATIONS a) General Specifications: This gives the nature, quality, class and work and materials in general terms to be used in various parts of wok. It helps no form a general idea of building. b) Detailed Specifications: These gives the detailed description of the vari- ous items of work laying down the Quantities and qualities of materials, their proportions, the method of preparation workmanship and execution of work. 1.4.3. RATES: For preparing the estimate the unit rates of each item of work are re- quired. 1. For arriving at the unit rates of each item. 2. The rates of various materials to be used in the construction. 3. The cost of transport materials. 4. The wages of labour, skilled or unskilled of masons, carpenters, Mazdoor, etc., 1.5 COMPLETE ESTIMATE: Most of people think that the estimate of a structure includes cost of land, cost of materials and labour, But many other direct and indirect costs included and is shown below. The Complete Estimate Cost of land P.s.and contingencies at 5% Legal expenses between owner and contractor Cost of Structure Actual cost of land Cost of Surveying Cost of Verification of deeds and execution of deeds Brochorage if any Cost of labour Permit fees for constrution water, electricity from concerned autorities cost of materials Consulting Engineers fees cost for preparation of plan, estimate and design Cost of supervision Introduction to the Subject 3 Estimation and Costing 1.6 LUMPSUM: While preparing an estimate, it is not possible to workout in detail in case of petty items. Items other than civil engineering such items are called lumpsum items or simply L.S.Items. The following are some of L.S. Items in the estimate. 1. Water supply and sanitary arrangements. 2. Electrical installations like meter, motor, etc., 3. Architectural features. 4. Contingencies and unforeseen items. Ingeneral, certain percentage on the cost of estimation is alloted for the above L.S.Items Even if subestimates prepared or at the end of execution of work, the actual cost should not exceed the L.S.amounts provided in the main estimate. 1.7 WORK CHARGED ESTABLISHMENT: During the construction of a project considerable number of skilled su- pervisors, work assistance, watch men etc., are employed on temporary basis. The salaries of these persons are drawn from the L.S. amount alloted towards the work charged establishment. that is, establishment which is charged directly to work. an L.S.amount of 1½ to 2% of the estimated cost is provided towards the work charged establishment. EXERCISE Short Answer Questions 1. State the requirements of an estimate? 2. Briefly Explain need for estimation? 3. What is work charged establishment? 4 2.1 UNITS OF MEASUREMENTS: The units of measurements are mainly categorised for their nature, shape and size and for making payments to the contractor and also. The principle of units of measurements normally consists the following: a) Single units work like doors, windows, trusses etc., are expressed in numbers. b) Works consists linear measurements involve length like cornice, fencing, hand rail, bands of specified width etc., are expressed in running metres (RM) c) Works consists areal surface measurements involve area like plastering, white washing, partitions of specified thickness etc., are expressed in square meters (m2) d) Works consists cubical contents which involve volume like earth work, cement concrete, Masonry etc are expressed in Cubic metres. [BASED ON IS 1200 REVISED] Particulas of item Earth work: 1. Earth work in Excavation 2. Earthwork in fillingin founda- tion trenches 3. Earth work in filling in plinth Concrete: 1. Lime concretre in foundation 2. Cement concrete in Lintels 3. R.C.C.in slab 4. C.C. or R.C.C. Chujja, Sun- shade 5. L.C. in roof terracing (thickness specified) Sl. No. I II Units of Measurement cum cum cum cum cum cum cum sqm Units of payment Per%cum Per%cum Per%cum percum percum percum percum persqm MEASUREMENT OF MA MEASUREMENT OF MA MEASUREMENT OF MA MEASUREMENT OF MA MEASUREMENT OF MATERIALS TERIALS TERIALS TERIALS TERIALS AND WORKS AND WORKS AND WORKS AND WORKS AND WORKS Chapter 2 5 Estimation and Costing 6. Cement concrete bed 7. R.C. Sunshade (Specified Width & Hight Damp ProofCource (D.P.C) (Thickness should be men- tioned) Brick work: 1. Brickwork in foundation 2. Brick work in plinth 3. Brick work in super struc- ture 4. Thin partition walls 5. Brick work in arches 6. Reinforced brick work (R.B.Work) Stone Work: Stone masonry Wood work: 1. Door sand windows frames or chowkhats, rafters beams 2. Shutters of doors and win- dows (thickness specified) 3. Doors and windows fittings (like hinges, tower bolts, sliding bolts, handles) Steel work 1. Steel reinforcement bars etc in R.C.C. and R.B.work. quintal 2. Bending, binding of steel Reinforcement 3. Rivets, bolts, & nuts, An- chor bolts, Lewis bolts, Holding down bolts. 4. Iron hold fasts 5. Iron railing (height and types specified) 6. Iron grills III IV V VI VII cum cum sqm cum cum cum sqm cum cum cum cum sqm Number Quintal Quintal Quintal Quintal Quintal sqm per cum 1rm persqm percum percum percum percum percum percum percum percum persqm per number per quintal per quintal per quintal per quintal per quintal per sqm 6 Roofing 1. R.C.C. and R.B.Slab roof (excluding steel) 2. L.C. roof over and inclusive of tiles or brick or stone slab etc (thickness specified) 3. Centering and shuttering form work 4. A.C.Sheet roofing Plastering, points&finishing 1. Plastering-Cement or Lime Mortar (thickness and pro- portion specified) 2. Pointing 3. White washing, colour washing, cement wash (number of coats specified) 4. Distempering (number of coats specified) 5. Painting, varnishing (number of coats specified) Flooring 1. 25mm cement concrete over 75mm lime concrete floor (including L.C.) 2. 25mm or 40mm C.C. floor 3. Doors and window sills (C.C. or cement mortar plain) Rain water pipe /Plain pipe Steel wooden trusses Glass pannels(supply) Fixing of glass panels or cleaning VIII IX X XI XII XIII XIV cum sqm sqm sqm sqm sqm sqm sqm sqm sqm sqm sqm 1RM 1No sqm No per cum per sqm per sqm per sqm per sqm per sqm per sqm per sqm per sqm per sqm per sqm per sqm per RM per 1No per sqm per no. Measurement of Materials and Works 7 Estimation and Costing 2.2 RULES FOR MEASUREMENT : The rules for measurement of each item are invaribly described in IS- 1200. However some of the general rules are listed below. 1. Measurement shall be made for finished item of work and description of each item shall include materials, transport, labour, fabrication tools and plant and all types of overheads for finishing the work in required shape, size and specification. 2. In booking, the order shall be in sequence of length, breadth and height or thickness. 3. All works shall be measured subject to the following tolerances. i) Linear measurement shall be measured to the nearest 0.01m. ii) Areas shall be measured to the nearest 0.01 sq.m iii) Cubic contents shall be worked-out to the nearest 0.01 cum 4. Same type of work under different conditions and nature shall be measured separately under separate items. 5. The bill of quantities shall fully describe the materials, proportions, workmanships and accurately represent the work to be executed. 6. In case of masonary (stone or brick) or structural concrete, the categories shall be measured separately and the heights shall be described: a) from foundation to plinth level b) from plinth level to First floor level c) from Fist floor to Second floor level and so on. 2.3 METHODS OF TAKING OUT QUANTITIES: The quantities like earth work, foundation concrete, brickwork in plinth and super structure etc., canbe workout by any of following two methods: a) Long wall - short wall method b) Centre line method. c) Partly centre line and short wall method. a) Long wall-short wall method: In this method, the wall along the length of room is considered to be long wall while the wall perpendicular to long wall is said to be short wall. To get the 8 length of long wall or short wall, calculate first the centre line lengths of individual walls. Then the length of long wall, (out to out) may be calculated after adding half breadth at each end to its centre line length. Thus the length of short wall measured into in and may be found by deducting half breadth from its centre line length at each end. The length of long wall usually decreases from earth work to brick work in super structure while the short wall increases. These lengths are multiplied by breadth and depth to get quantities. b) Centre line method: This method is suitable for walls of similar cross sections. Here the total centre line length is multiplied by breadth and depth of respective item to get the total quantity at a time. When cross walls or partitions or verandah walls join with mainall, the centre line length gets reduced by half of breadth for each junction. such junction or joints are studied caefully while calculating total centre line length.The estimates prepared by this method are most accurate and quick. c) Partly centre line and partly cross wall method: This method is adopted when external (i.e., alround the building) wall is of one thickness and the internal walls having different thicknesses. In such cases, centre line method is applied to external walls and long wall-short wall method is used to internal walls. This method suits for different thicknesses walls and diffeent level of foundations. Because of this reason, all Engineering departments are practicing this method. Measurement of Materials and Works 9 Estimation and Costing P.B.-1: From the Drawing given below determine (a) Earth work exca- vation (b) CC (1:5:10) Bed (c) R.R.Masonry in C.M. (1:6) (d) Brick Work in C.M.(1:6). Single Roomed Building (Load Bearing type structure) Note: All Dimensions are in 'M' 10 1. 2. 3. 4. Earth Work excavation for foundation a) Long walls b) Short walls C.C.(1:4:8) bed for foundation a) Long walls b) Short walls R.R.Masonry in CM (1:6) for a) Footings i) Long walls ii) Short walls b) Basement i) Long walls ii) Short walls Brick masonary with CM (1:6) for super structure a) Long Wall b) Short walls 2 2 2 2 2 2 2 2 2 2 6.2 3.4 6.2 3.4 0.9 0.9 0.9 0.9 0.6 0.6 0.45 0.45 0.30 0.30 1.4 1.4 Total 15.264 8.568 24.192 3.348 1.836 5.184 3.54 2.22 5.76 3.105 2.079 5.184 10.08 7.20 17.28 L=5.3+.45+.45 =6.2 D= 0.3+0.5+0.6 = 1.4 L= 4.3-0.45-0.45= 3.4 L= 5.3+0.3+0.3=5.9 L=4.3-0.3-0.3 = 3.7 L= 5.3+0.225+0.225= 5.75 L= 4.3-0.225-0.225 =3.85 L=5.3+0.15+0.15=5.6 L=4.3-0.15-0.15=4.0 S.No. Particulars of Items No. L B H Q Explanation Total R.R. Masonry for footings and Basement = 5.76+5.184 = 10.94 m3 0.3 0.3 Total 0.5 0.5 Total 0.6 0.6 Total 3.00 3.00 Total 5.9 3.7 5.75 3.85 5.6 4.0 m3 m3 m3 m3 m3 Long wall - Short wall Method Measurement of Materials and Works 11 Estimation and Costing 1. 2. 3. 4. Earth Work excavation for foundation C.C.(1:4:8) bed for foundation R.R.Masonry in CM (1:6) for a) Footings b) Basement Brick masany with CM (1:6) for super structure 1 1 1 1 1 19.2 19.2 19.2 19.2 19.2 0.9 0.9 0.6 0.45 0.3 1.4 0.3 0.5 0.6 Total 0.3 24.192 5.184 5.76 5.184 10.944 17.28 L=2(5.3+4.3)=19.2 S.No. Particulars of Items No. L B H Q Explanation Centre Line Method 5.3 4.3 m3 m3 m3 m3 12 EXERCISE I. Short Answer Questions 1. List the difference between centre line method and long wall-short wall method of taking out measurements. 2. What are the rules to be followed while taking the mesurements? 3. Mension the units for the following items. a) flooring b) R.R.Masonry c) Plastering for pointing d) Damp proof course e) R.C. sunshade (Sepcified width and thickness) II. Essay type questions 1. From the Drawing given below determine (a) Earth work excavation (b) CC (1:5:10) Bed (c) R.R.Masonry in C.M. (1:6) (d) Brick Work in C.M.(1:6). by (a) longwall - short wall method (b) Centre line Method Measurement of Materials and Works