Willis's Elements of Quantity Surveying (eBook)

Sandra Lee (Autor)

eBook Download: EPUB

2020 | 13. Auflage
John Wiley & Sons (Verlag)
978-1-119-63319-8 (ISBN)

Infos

Willis's Elements of Quantity Surveying has become a standard text in the teaching of building measurement - a core part of the degree curriculum for quantity surveyors. The book will be fully updated to follow the guidance given by RICS NRM 1 & 2. As in previous editions the focus remains a logical approach the detailed measurement of building elements and copious use of examples to guide the student. The text has been fully revised in line with the NRM guidance and includes many new and revised examples illustrating the use of NRM. The hallmarks of previous editions - clarity and practicality - are maintained, while ensuring the book is fully up to date, providing the student of quantity surveying with a first class introduction to the measurement of building elements.

SANDRA LEE is a retired Chartered Quantity Surveyor but continues to be involved with surveying education and the associated professional bodies.

Inhalt

Preface vii

Acknowledgements ix

Abbreviations xi

About the Companion Website xiii

1 Introduction 1

2 Detailed Measurement 5

3 The Use of the RICS New Rules of Measurement (NRM) 11

4 Setting Down Dimensions 21

5 Alternative Systems 41

6 Preliminary Calculations 49

7 General Principles for Taking-Off 57

8 Substructures 73

9 Walls 103

10 Floors 127

11 Roofs 139

12 Internal Finishes 173

13 Windows and Doors 185

14 Reinforced Concrete Structures 207

15 Structural Steelwork 221

16 Plumbing 231

17 Drainage 251

18 External Works 261

19 Preliminaries and Other Priced Bill Sections 273

20 Bill Preparation 279

Appendix: Mathematical Formulae and Applied Mensuration 297

Index 315

Textauszug

Chapter 3
The Use of the RICS New Rules of Measurement (NRM)

Background

The New Rules of Measurement (NRM) Project was arguably one of the most significant developments in quantity surveying practice since the publication of the SMM7 in 1988. The intention of the Royal Institution of Chartered Surveyors (RICS) with this publication is to create a set of common rules that provide a consistent approach to measurement through the various stages of a project, from initial cost estimate to detailed quantification of the construction work. Whilst the NRM is based on UK practice, it is nevertheless intended to have worldwide application.

This chapter therefore looks at the key features of the NRM in order to explain how it relates to the measurement covered in this text.

Historically, surveyors would approach the measurement of approximate quantities in different ways: for example, the area of external walls might be measured over windows and doors (i.e. gross measurement) by one surveyor, whilst another might deduct the area of the windows and doors (i.e. net measurement). The method of measurement would be closely related to the way in which the rates were to be applied. This variation in practice then resulted in an inconsistent approach to early estimates and cost planning, which then led to further problems when cost plans were used instead of bills of quantities as the basis of tender negotiations. Cost plans would then be analysed and used as benchmarks for further cost plans, thus creating an unreliable database and potentially inaccurate estimates. There was also a lack of continuity in cost data between cost plans and bills of quantities, making it almost impossible to reconcile the cost plan with the priced bill of quantities or pre‐tender estimate.

The NRM volumes

The RICS has published a suited set of documents in three volumes, for the measurement of building work from the early feasibility stage through to completion, handover, and building occupation. The full NRM comprises:

Volume 1 (NRM1) – Order of Cost Estimating and Elemental Cost Planning, covering:

• Estimating – Royal Institute of British Architects (RIBA) Work Stage 1; Office of Government Commerce (OGC) Gateways 1 and 2.
• Cost planning – Elements – RIBA Work Stages 2–4; OGC Gateways 3A, 3B, and 3C.

Volume 2 (NRM2) – Construction Quantities and Works Procurement, covering:

• RIBA Work Stages 5 and 6; OGC Gateway 3C (detailed measurement for tender documentation).

Volume 3 (NRM3) – Maintenance and Operation Cost Planning and Procurement, covering:

• RIBA Work Stage 7; OGC Gateways 4 and 5 (life cycle costing).

Volume 1 – order of cost estimating and cost planning for capital building works

This volume provides guidance on the quantification of building works for the purpose of preparing early cost estimates and cost plans. In addition, it gives direction on how to quantify other factors including preliminaries, overheads and profit, project team and design team fees, risk allowances, and inflation.

Contents:

• Part 1: General. This places cost estimating and elemental cost planning in context and includes the RIBA Plan of Work and the OGC Gateway methodology definitions used in the rules.
• Part 2: Measurement rules for order of cost estimating. This describes the purpose and content of an order of cost estimate; defines its key constituents and explains how to prepare an order of cost estimate; and sets out the rules of measurement for the preparation of order of cost estimates using the floor area method, functional unit method and elemental method.
• Part 3: Measurement rules for cost planning. This describes the purpose of formal elemental cost plans, explains their key constituents and explains how to prepare an elemental cost plan.
• Part 4: Tabulated rules of measurement for elemental cost planning. This comprises the detailed tabulated rules of measurement for the preparation of approximate quantities for formal elemental cost plans.
• Appendices include definitions of gross internal floor area (GIFA), net internal area (NIA), measurement rules for the element unit quantity (EUQ), information requirements for formal cost plans and templates for elemental cost plans.

For those not familiar with the RIBA works stages, these are included in Table 1.

Table 1 RIBA work stages (excluding Stage 0)

RIBA stages

NRM cost stages

Quantity surveyor action

1

Preparation and brief

Order of cost estimate

Estimate developed from cost per functional unit through to cost per square metre and high‐level elemental cost per GIFA

2

Concept design

Formal Cost Plan 1

Develops order of cost estimate through to an elemental cost plan based on element unit quantities

3

Developed design

Formal Cost Plan 2

As more design information is released, greater detail can be included in the cost plan

4

Technical design

Formal Cost Plan 3 pre‐tender estimate

Cost checks undertaken Bills of quantities may be measured where required by the procurement approach being used

5

Construction

Agreement of variations and payments for work completed Analysis of tender costs

6

Hand‐over and close‐out

Settlement of any claims and final account

7

In use

Evaluation of project undertaken Checks made against original cost targets

Table 2 Structure of the order of cost estimate

Ref.

Items

Currency

1

Building works

2

Main contractor preliminaries

3

Main contractor overheads and profit

4

Works cost estimate Project/design team fees

5

Other development/projects costs

6

Base estimate Risk allowances: Design development risks Construction risks Employer change risks Employer other risks

7

Cost limit (excluding inflation) Inflation: Tender inflation Construction inflation

Cost limit (including inflation)

The structure of an order of cost estimate is the same as that of Formal Cost Plan 1, thus enabling a consistent approach to be taken as further design details become available (see Tables 2 and 3). The rules of measurement, however, differ by taking into account the level of design detail available at each stage.

The different rules for the order of cost estimate as opposed to the elemental cost plan can be found by comparing Volume 1 Part 2 with Part 3.

Part 2, Section 2.6 contains the measurement rules for building works which give two alternatives depending on the level of information available.

• The floor area method (GIFA × appropriate cost per square metre).
• The functional unit (functional unit, including all circulation space × appropriate rate per unit, i.e. the number of hospital beds or area of retail shops).

Part 2, Section 2.7 gives direction on the use of the elemental method at this early stage for elements where the information exists. The elements are those listed in Table 3. It is important to note that there can still be optional approaches as the design detail for some elements may not be available. For example, if the external wall details are not available, the cost of this element can be found by taking the GIFA × a rate per square metre of the GIFA. If, however, the construction of the walls and windows is known, the cost would be the area of the walls (EUQ) multiplied by a suitable rate per square metre (element unit rate or EUR) of the walling. The method of measuring and the units are, then, those contained in Appendix E of Volume 1.

Table 3 Structure of Formal Cost Plan 1

Cost centre

Group element/element

Cost per square metre of the GIFA

Total cost of element (target cost)

Currency

Currency

Building works

0

Facilitating works

...

1

Substructure

Produkt-Details

• Erscheint lt. Verlag: 23.6.2020
• Sprache: englisch
• Themenwelt: Technik ► Bauwesen
• Schlagworte: Bauingenieur- u. Bauwesen • Bauwesen • bill preparation appendix • Civil Engineering & Construction • General Principles • Massenermittlung u. Bauökonomie • Measurement • NRM • Quantity Surveying & Construction Economics • rics new rules • WINDOWS
• ISBN-10: 1-119-63319-2 / 1119633192
• ISBN-13: 978-1-119-63319-8 / 9781119633198