Module 1 - CMG2002 The basic principles of measurement of building and civil works V2 PDF

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CMG2002 Cost Management: Estimating, Measurement and Cost Control

Module 1 – The basic principles of measurement of building and civil works Contents 1.1. Introduction to estimating ............................................................................................................ 3 1.2. Measurement of quantities ........................................................................................................... 3 1.3. The differences between building and civil estimating measurement ......................................... 4 1.4. Measurement in accordance with the Australian Standard Method of Measurement of Building Works (ASMM) – 6th edition ..................................................................................................... 8 1.5. Builders’ quantities .................................................................................................................... 10 1.6. Preparation of a BoQ including preamble.................................................................................. 11 1.7. Basic set out principles of measurement and nomenclature ...................................................... 13 1.7.1. Increments......................................................................................................................... 14 1.7.2. A precis of ASMM nomenclature..................................................................................... 15 1.8. Measurement of area types ........................................................................................................ 20 1.9. Measurement take-off techniques, including deductions ........................................................... 21 1.9.1. Manual take-off ................................................................................................................ 21 1.9.2. Take off Industry Practice ................................................................................................ 22 1.9.3. Fast methods of taking off quantities................................................................................ 23 1.9.4. Take-off Principles ........................................................................................................... 23 1.9.5. Deductions ........................................................................................................................ 23 1.9.6. Digital take-off.................................................................................................................. 23

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CMG2002 – Cost Management: Estimating, Measurement and Cost Control

Module 1 – The basic principles of measurement of

building and civil works Learning resources AS1181-1982: Method of Measurement of Civil Engineering Works and Associated Building Works, Australian Standards (Recommended) Australian Standard Method of Measurement of Building Works – 6th Edition (2016), Australian Institute of Quantity Surveyors (AIQS) (Recommended) Building Measurement – 2nd Edition (1998), Paul Marsden, University of NSW Press. Construction Quantity Surveying: A Practical Guide for the Contractor's QS (2012), Donald Towey, Wiley-Blackwell (Recommended) Cordell Housing Building Cost Guide (2016), Reed Construction Data Cost Management Manual - Volume 1: Cost Planning and Cost Analysis – 3rd Edition (2009), Australian Institute of Quantity Surveyors (AIQS) (Recommended) Estimating for Building & Civil Engineering Works – 9th Edition (1996), Spence Geddes, Butterworth-Heinemann Guide to Estimating Practice for Building Work – 6th Edition (1995), Australian Institute of Building (AIB) (Recommended) Rawlinsons Construction Cost Guide (2016), Rawlinson Publications

Selected Readings

Reading 1.1: Reading 1.2: Reading 1.4: Reading 1.5: Reading 1.6: Reading 1.7: Reading 1.8: Reading 1.9: Reading 1.10: Reading 1.11:

Appendix 1 – Building bill of quantities Appendix 2 – Civil Engineering price schedule Appendix 27 – Tender Summary Appendix 29 – Window schedule Appendix 50 – Priced bill of builders quantities - control room building Appendix 51 – Direct cost estimate - Control room building, builders’ quantities Appendix 53 – Road Bridge - Estimate Summary Appendix 54 – Road Bridge - Direct Cost Summary Appendix 66 – Cost plan example NATSPECS – NATIONAL CLASSIFICATION SYSTEM - OCTOBER 2016

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CMG2002 Cost Management: Estimating, Measurement and Cost Control

1.1. Introduction to estimating The term Estimate derives from the Latin "aestimat" meaning valuing, or a calculation of the number, quantity, or extent of something for valuation. Estimating is therefore the process of calculating the cost of constructing a project and is often classed under the umbrella term of building economics. Estimating involves the systematic process of identifying and analysing the scope of works of a project from the documentation supplied, managing this information, quantifying the project and then calculating the cost of the materials, labour, plant, overheads and margins required to complete the project. This requires the assessment of material quantities, labour allowances, negotiations with suppliers and sub-contractors and the recording of all the data obtained, in a succinct and standardised format. Speed and accuracy are the essence of estimating. An estimator has to quickly grasp the extent of work in a project and price it… often within very short timeframes. An inaccurate and poor attempt at pricing a tender will result in a high and uncompetitive price. Conversely, an erroneous low estimate could result in winning the project and running the project at a loss. An accurate, keen tender estimate is the essential starting point for undertaking a contract to construct a project.

1.2. Measurement of quantities An essential component of the estimating process, is the accurate measurement of quantities. Historically, building quantity measurement has been performed by quantity surveyors, with civil engineering quantities by consulting engineers. For an audio visual presentation on the work of a quantity surveyor, check the following link:

https://www.youtube.com/watch?v=nF3Wth8h9xU Typical methods of measuring major projects are: 

In Australia, building project quantities are measured in a format known as a Bill of Quantities (BoQ). BoQs follow the procedure as set out in “The Australian Standard Method of Measurement” (ASMM) – currently in its 6th edition (2016) – which is produced by the Australian Institute of Quantity Surveyors and published by the Australian Institute of Quantity Surveyors and Master Contractors Australia Incorporated… see links below: http://www.mastercontractors.com.au/Products/standard-method-of-measurement or https://www.aiqs.com.au/imis/AIQS_Website/News/ASMM6.aspx This is the commonly used method of measuring building works for government, institutional and traditional clients. The current format also relates to the NATSPEC trades.

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CMG2002 – Cost Management: Estimating, Measurement and Cost Control

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In Australia, civil engineering project quantities are measured in a format known as a pricing or tender schedule, which follow the procedures set out in Australian Standard, AS1181-1982: Method of Measurement of Civil Engineering Works and Associated Building Works. Refer: https://www.saiglobal.com/pdftemp/previews/osh/as/as1000/1100/1181.pdf The schedule is generally used on civil and infrastructure projects, particularly where the project team leader has an engineering background. For an audio visual presentation on measuring Civil re-engineering works:

https://www.youtube.com/watch?v=k4bFIPzBqss

1.3. The differences between building and civil estimating measurement A BoQ is a list of the materials, labour and services required to complete a building construction project. It is generally set out in the order of the trades, and provides a basis for building companies to tender for jobs on a common basis. Typically, in a BoQ prepared by a Chartered Quantity Surveyor, the accuracy of the quantities is guaranteed between certain accuracy limits. A major point of difference is in the division of trades. As per ASMM 6, in structural trades for say a concrete column, the concrete, reinforcing steel and formwork for a particular item are measured and priced separately refer to Appendix 1 for a complete BoQ (Courtesy of WT Partnership Quantity Surveyors). As you will see, the Concrete – pages 4/1 through 4/9 – the Concrete Formwork – pages 5/1 through to 5/5 – and the Concrete Reinforcing – page 6/1 through 6/5 – are all measured and priced separately. Most building estimates generally conform to the ASMM6 trade format. Conversely, in civil engineering, estimating is as per AS 1181 – 1982, where the pricing format is typically called a pricing schedule. These pricing schedules are not done to a set generic format. For example, refer the following differing price schedule formats:

Reading 1.2: Reading 1.8:

Appendix 2 – Civil Engineering price schedule Appendix 53 – Road Bridge - Estimate Summary

Both these projects differ in format and set out. This is possibly due to the wide range of civil engineering projects which have little in common as follows:      

Bridges Roads Dams Subdivisions Stormwater drainage Sewer drainage

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CMG2002 Cost Management: Estimating, Measurement and Cost Control

      

Sewage/water treatment plants Mine and mine infrastructure Rail lines Dredging Port infrastructure Dams Retaining structures

Note: Appendix 2 – Civil Engineering Price Schedule – includes the Queensland Transport and Main Roads (TMR) item description nomenclature identifier, which is widely used in Queensland Civil Engineering pricing schedules. Further, most quantities given in pricing schedules are not guaranteed. Typically the contract will state that the price schedule does not form part of the contract and that the price schedule is for variation pricing only. Naturally the price schedule total does form the contract sum! Formats also differ. Typically when pricing concrete works, in most pricing schedules, the rate for concrete will roll up or include the concrete in m3 including the formwork (which is not measured separately). Reinforcing is measured in tonnes. An example of this is shown in Appendix 2, with TMR Code 8304.01 “Concrete Class [compressive strength] MPa/20 in parapet and parapet terminal m3” (note: formwork not measured) and TMR Code 8311.01 “Reinforcing steel in decks, cross girders, kerbs and parapets, excluding parapet terminals”. Similarly, in Appendix 54 – USQ Road Bridge Direct Cost Summary – on page 1, section 3, the Concrete Works shows the concrete in piers, pile caps, columns and headstocks, all measured separately, followed by the total weight of the reinforcing steel (both bar and fabric included in the same quantity) in tonnes, despite AS 1181-1982 indicating that they should be measured separately. Note that the formwork has not been measured and is deemed to be included in concrete rate build-up, along with the labour to install it. Civil engineering formwork can be quite complex and expensive but is commonly not measured separately even though it is described in AS1181. Hence extreme care should be taken when pricing civil works to ensure that such items are considered, priced and incorporated into the estimate. The differences in the “trade” scope is highlighted further, in the following ASMM/AS 1181 – similar trade comparison table, below: Table 1. 1 ASMM/AS 1181 – similar trade comparison table

ASMM 1 Introduction, general rules and recommendations

AS 1181 Section 1. Scope and General

2 Preliminaries

Section 2. Preliminaries

3 Demolition

Section 4. Site Clearance and Demolition

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CMG2002 – Cost Management: Estimating, Measurement and Cost Control Section 3. Site Investigation 3.1 General 3.2 Test Pits 3.3 Boreholes and Pumping Test Wells 3.4 Samples 3.5 Tests Including Reports 3.6 Site Instrumental Observations

4 Groundworks:

Section 5. Excavation and Filling

4.1 Excavation 4.2 Filling and hard core 4.3 Paper and plastic membranes 4.4 Underpinning 4.5 Rock stabilisation

5.1 Excavation 5.2 Filling

Section 6. Tunnels and Shafts

Section 7. Dredging 5 Piling:

Section 8. Piling and Caissons

5.1 Driven piling

8.2 Precast Concrete, Timber and Steel Piles

5.2 Cast in-situ piling

8.3 Driven Cast-in-place Piles 8.4 Bored Cast-in-place Piles and Caissons 8.5 Sheet Piling Section Section 10. Railway Track work 10.1 General and Definitions 10.2 Tracks On or In Concrete Slabs

6 Concrete: 6.1 In-situ Concrete 6.2 Formwork

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Section 11. Concrete 11.2 In-situ Concrete 11.2.3 Formwork

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CMG2002 Cost Management: Estimating, Measurement and Cost Control 6.3 Permanent metal formwork system 6.4 Reinforcement 6.5 Prestressing 6.6 Slip formed construction 6.7 Precast concrete 6.8 Tanking

11.2.4 Reinforcement 11.4 Prestressed Concrete

7 Masonry

Section 12. Brickwork and Blockwork

11.3 Precast Concrete.

8 Stonework: 8.1 Natural stonework 8.2 Artificial stone, terracotta and similar work 9 Structural steel

Section 13. Structural Steel and Metalwork

10 Metalwork

Section 13. Structural Steel and Metalwork

11 Woodwork

Section 14. Carpentry, Joinery and Ironmongery

12 Glazing

Section 22. Glazing

13 Hardware

Section 14. Carpentry, Joinery and Ironmongery

14 Access floors 15 Partitions 16 Roofing

Section 15. Roofing, Roof Plumbing and Wall Cladding 16.1 Sheet metal Work

17 Suspended ceilings 18 Windows 19 Doors

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CMG2002 – Cost Management: Estimating, Measurement and Cost Control 20 Finishes: 20.1 In-situ applied finishes 20.2 Metal lathing 20.3 Plasterboard, fibrous plaster, plaster acoustic tiles 20.4 Tile, slab, block or sheet finishes, paving and carpets

Section 20. Plastering Section 20. Plastering Section 21. Paving, Tiling and Terrazzo Works

20.5 Division strips and inserts 21 Painting

Section 23. Painting

22 Furniture 23 Hydraulics

Section 16. Sheet metal Work and Sanitary Plumbing and Piped Services

16.2 Sanitary Plumbing and Piped Services 24 Drainage

Section 17. Water Mains, Sewerage and Drainage

25 Electrical Installations

Section 18. Electrical Conduits

26 Mechanical installations

Section 19. Engineering Services

27 Exterior elements: 27.1 Landscaping 27.2 Roadworks

Section 9. Roads and Paving

By the gaps in each trade category publication, it can be clearly seen the differing emphasis between building scope of works and civil engineering scope of works.

1.4. Measurement in accordance with the Australian Standard Method of Measurement of Building Works (ASMM) – 6th edition The purpose of the ASMM is to provide a uniform basis for the measurement of building works. In larger commercial projects, Bills of Quantities (BoQs) are typically used to assist the builder to arrive at a fairly accurate tender figure.

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CMG2002 Cost Management: Estimating, Measurement and Cost Control A BoQ is a list of the materials, labour and services required to complete a construction project. It is generally set out in the order of building trades. The advantages of using a professionally prepared BoQ on a building project, are as follows:       

Allows for a consistent and transparent comparison of builder’s tenders Ensures that a builder’s tender is complete Is a concise basis for the valuation of progress claims The use of BoQ rates provides a clear basis for valuing variations Assists in the calculation of the project’s cost to complete Speeds up the tender process by saving builder’s time and expense in individually taking off, describing and quantifying the scope of works Assists in the post-tender analysis of the estimate, in a cost plan format, for future projects.

It is important that students carefully peruse ASMM6 Chapter 1, Introduction, general rules and recommendations. ASMM6 has evolved from the UK ASMM and supersedes ASMM5. As per the introduction:    

1.1 “The purpose of this document is to provide a uniform basis for the measurement of building works”. 1.2 “The methods of measurement described in ASMM6 shall be applicable to the preparation of BoQ”. The method does allow some flexibility as per 1.3. 1.3 “More detail than is required by this document should be given”.

An example of this, is the ability to include non-standard trades. Refer to Appendix 1, page 21/1, where Section 32 indicates a “Cell Systems and Fitout” trade. This is due to the project being a specialised security detention building, containing unique fittings for which ASMM has no provision. However, this has not stopped the quantity surveyor from measuring these fittings in great detail. As indicated previously, the BoQ is typically produced in a trade format, with the various trades being grouped to align with the nationally adopted NATSPEC specification system; as published by NATSPEC. (See http://www.natspec.com.au/) To see the similarities, compare the ASMM Categories shown in Table 1. 1 with NATSPEC’s NATIONAL CLASSIFICATION SYSTEM - OCTOBER 2016 (Selected Reading 1.1). Where the project specification does not follow this system or where further sub-division to facilitate sub-contract pricing is deemed necessary, cross reference should be made in the BoQ to the appropriate section of measurement used. In special cases, BoQs can be prepared in elemental or activity formats to suit particular client requirements. All BoQs should state clearly the method of measurement used. Where departures are made from the written method, these should be clearly identified. Normal practices to be followed in preparing BoQs include:  

Each item in the BoQ shall be individually numbered. Descriptions shall adequately describe materials and workmanship when read in conjunction with the specification, drawings and other contract documents to enable pricing of the works. Locational information may be included in the description.

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CMG2002 – Cost Management: Estimating, Measurement and Cost Control

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A separate trades section should be included to cover Provisional Sums. Sums shall be designated in the same manner that they are designated in the Specification. Cross references shall be given in the appropriate trades to work covered by Provisional Sums. Where work cannot be measured to accurately represent the quantities of work to be executed, “Provisional Quantities” shall be measured and given as a separate item or items. Such quantities may be spread across the trades with a separate schedule summarising the extent. Particular care shall be taken that reference to all provisional works is included in the Specification. BoQs should be prepared to the same degree of accuracy whether they are guaranteed by the contract or to be used for information only.

For an example of a complete BoQ, refer to Appendix 1 – Building BoQ (Courtesy W...