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- Herausgeber: John Wiley & Sons
- Kategorie: Wissenschaft und neue Technologien
- Sprache: Englisch
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.
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Table of Contents
Cover
Preface
Acknowledgements
Abbreviations
About the Companion Website
Chapter 1: Introduction
The modern quantity surveyor
The need for measurement
The need for rules
Establishing the approach
Method of study
Examples
Chapter 2: Detailed Measurement
Method of analysing cost
Origin of the bill of quantities
The measurement process
Attributes of a quantity surveyor
Divisions of bill preparation
Quantities as part of the contract
Contractor‐produced quantities and estimates
Differences of custom
Chapter 3: The Use of the RICS
New Rules of Measurement
(NRM)
Background
The NRM volumes
Volume 1 – order of cost estimating and cost planning for capital building works
The potential benefits of using NRM1
Introduction to NRM2
Chapter 4: Setting Down Dimensions
Traditional dimension paper
Form of dimensions
Timesing
Dotting on
Waste calculations
Alterations in dimensions
The descriptions
Anding‐on
Deductions
Spacing of dimensions
Accuracy
Numbering the dimension sheets
Cross‐references
Clearness of the dimensions
Headings
Insertion of items
Squaring the dimensions
Scheduling dimensions
Chapter 5: Alternative Systems
Standardisation
Standard libraries
Computerised bill production
E‐tendering
Site dimension books
Estimating paper
Chapter 6: Preliminary Calculations
Mathematical knowledge
Perimeter of buildings
Centre line of the wall
Chapter 7: General Principles for Taking‐Off
Receipt of the drawings
Preliminary study of drawings
Queries with the designers
Initial site visit
Where to start
Organising the work
Sections of taking‐off
Taking‐off by work sections
Drawings
The specification
Materials
Sequence of measurement
Measurement of waste
Overall measurements
Use of schedules
Use of scales
Use of NRM2
Decision on doubtful points
Descriptions
Abbreviations
Extra over
Dimensioned diagrams
Prime cost items and provisional sums
Approximate quantities
Summary
Chapter 8: Substructures
Particulars of the site
Bulking
Removing topsoil
Bulk excavation
Excavation for paths
Levels
Foundation excavation
Earthwork support
Disposal of excavated material
Working space
Concrete foundations
Concrete ground slab
Brickwork and blockwork in foundations
Damp‐proof courses
Approach taken to measurement in Example 1
Chapter 9: Walls
Measurement of brickwork
Subdivision
Measurement of projections
Descriptions
Brickwork thickness
Common and facing brickwork
Cutting, grooves, and the like
Returns and reveals
Hollow (cavity) walls
Ornamental bands
Special purpose blocks or stones
Reinforcement
Measurement of arches
Blockwork
Rendering
Stonework
Internal partitions
Chapter 10: Floors
Timber sizes
Subdivision
Timber floor construction
Staircases
Concrete floors
Precast concrete beam and pot floors
Chapter 11: Roofs
Subdivision
Pitched roof construction
Roof slopes
Hips and valleys
Broken‐up roofs
Trussed rafters
Tile or slate roof coverings
Eaves and verge finish
Rainwater installation
Flat roofs
Chapter 12: Internal Finishes
Schedules
Subdivision
Generally
Floor finishes
Ceiling finishes
Wall finishes
Angle beads and so on
Decoration
Cornices and coves
Skirtings
Wall tiling
Internal partitions
Dry wall linings
Chapter 13: Windows and Doors
Subdivision
Schedules
Timesing
Special features
Dormer windows
Adjustments
Windows and doors
Glass
Ironmongery
Decoration
Openings
Chapter 14: Reinforced Concrete Structures
Generally
Columns
Structural floors and roofs
Beams
Walls
Reinforcement
Approach to measurement
Chapter 15: Structural Steelwork
Fittings
Chapter 16: Plumbing
Subdivision
Sanitary appliances
Foul drainage above ground
Cold water
Hot water
Chapter 17: Drainage
Subdivision
Manholes
Drain runs
Chapter 18: External Works
Particulars of the site
Coverage
Site preparation
Excavation
Roads and paving
Walling
Fencing
Sundry furniture
External services
Chapter 19: Preliminaries and Other Priced Bill Sections
Generally
Preliminaries and general conditions section
Part A
Part B
Chapter 20: Bill Preparation
Abstracting
Procedure
Division into sections
Structure of bills
General principles
Order of items in the bill
Format of the bill
Referencing items
Units of measurement
Order of sizes
Use of headings
Writing short
Unit of billing
Framing of descriptions
Totalling pages
Summary
The process of checking
Numbering pages and items
General final check
Cover and contents
Other bill types
Bill of approximate quantities
Schedule of prices or rates
Appendix: Mathematical Formulae and Applied Mensuration
Formulae for areas (A) of plane figures
Regular polygons
Irregular figures
Formulae for surface areas (SA) and volume (V) of solids
Irregular areas
Measurement of arches
Excavation to banks
Excavation to sloping sites
Grids of levels
Example of weighted average excavation
Interpolation of levels
Index
End User License Agreement
List of Tables
Chapter 3
Table 1 RIBA work stages (excluding Stage 0)
Table 2 Structure of the order of cost estimate
Table 3 Structure of Formal Cost Plan 1
Table 4 Extract from Section 3 of NRM2
List of Illustrations
Chapter 4
Fig. 1
Fig. 2
Chapter 5
Fig. 3
Chapter 6
Fig. 4
Fig. 5
Fig. 6
Fig. 7
Fig. 8
Chapter 7
Fig. 9
Chapter 8
Fig. 10
Fig. 11
Fig. 12
Fig. 13
Fig. 14
Fig. 15
Chapter 9
Fig. 16
Fig. 17
Fig. 18
Fig. 19
Chapter 10
Fig. 20
Fig. 21
Fig. 22
Chapter 11
Fig. 23
Fig. 24
Fig. 25
Fig. 26
Fig. 27
Fig. 28
Fig. 29
Fig. 30
Fig. 31
Chapter 12
Fig. 32
Fig. 33
Chapter 13
Fig. 34
Fig. 35
Chapter 14
Fig. 36
Chapter 15
Fig. 37
Chapter 16
Fig. 38
Chapter 17
Fig. 39
Fig. 40
Fig. 41
Chapter 18
Fig. 42
Chapter 20
Fig. 43 Taking‐off.
Fig. 44 Abstract.
Fig. 45
Appendix
Fig. A.1
Fig. A.2
Fig. A.3
Fig. A.4
Fig. A.5
Fig. A.6
Fig. A.7
Fig. A.8
Guide
Cover
Table of Contents
Begin Reading
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Willis's Elements of Quantity Surveying
Thirteenth Edition
Sandra Lee
MSc, FRICS, MCIOB
This edition first published 2020© 2020 John Wiley & Sons Ltd
Edition History(1998 9e Blackwell Science), (2005 10e Blackwell Publishing Ltd), (2011 11e John Wiley & Sons Ltd), (2014 12e John Wiley & Sons Ltd)
All rights reserved. No part of this publication may be reproduced, stored in a retrieval system, or transmitted, in any form or by any means, electronic, mechanical, photocopying, recording or otherwise, except as permitted by law. Advice on how to obtain permission to reuse material from this title is available at http://www.wiley.com/go/permissions.
The right of Sandra Lee to be identified as the author of this work has been asserted in accordance with law.
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Library of Congress Cataloging‐in‐Publication Data
Names: Lee, Sandra, 1953‐ author.
Title: Willis's elements of quantity surveying / Sandra Lee.
Description: Thirteenth edition. | Hoboken, NJ : John Wiley & Sons, Inc., 2020. | Includes index.
Identifiers: LCCN 2020008847 (print) | LCCN 2020008848 (ebook) | ISBN 9781119633181 (paperback) | ISBN 9781119633204 (adobe pdf) | ISBN 9781119633198 (epub)
Subjects: LCSH: Building--Estimates. | Quantity surveying.
Classification: LCC TH435 .W685 2020 (print) | LCC TH435 (ebook) | DDC 692/.5--dc23
LC record available at https://lccn.loc.gov/2020008847
LC ebook record available at https://lccn.loc.gov/2020008848
Cover Design: Wiley
Cover Image: © teekid/Getty Images
Preface
This book was first published in 1935, and in the preface to that first edition it stated that it was intended ‘to be a book giving everything in its simplest form and to assist a student to a good grounding in first principles’. Each successive edition has been brought up to date; however, we have always striven to maintain the original guiding principles, which are as relevant today as they were over 80 years ago.
The text is intended to be studied as part of a measurement module or course with the support of a tutor and other appropriate study materials. A basic skill of being able to read drawings and knowledge of the construction of the works being measured is also required prior to starting to work through the examples in this text.
Whilst the use of the traditional bill of quantities continues to decline and today is only one of a variety of options open to the industry for the procurement of construction contracts, nevertheless, the skills of measurement are still very much required in some form or another under most procurement routes.
This edition utilizes the measurement rules to be found in the publication by the Royal Institution of Chartered Surveyors (RICS) of the second volume of the New Rules of Measurement – Detailed Measurement for Building Works (NRM2).
The basic structure of the book generally follows that of previous editions, setting down the measurement process from first principles and assuming the reader is coming fresh to the subject.
Whilst it is recognised that modern computerised measurement techniques utilising standard descriptions might appear far removed from traditional taking‐off, it is only by fully grasping such basic principles of measurement that they can be adapted and applied to alternative systems. It is for this reason that the examples continue to be written in traditional form.
The book opens with an overview of the need for measurement and the differing rules governing measurement at different stages of the design or project cycle. The main focus of the book remains on the detailed measurement of elements of a building using the rules from NRM2 and concludes with guidance on how to use the data collected during the measurement process to create the tender documents.
Whilst the role of the quantity surveyor is subject to continual change, we hope that students will find this book as useful as their predecessors have.
Sandra Lee
Acknowledgements
The continued publication of this text would not be possible without the considerable input of the previous authors William Trench and Andrew Willis over the last 30 years.
The efforts of Ruth Pearson, are gratefully acknowledged for the preparation of the drawings.
Abbreviations
a.b.
as before
a.b.d.
as before described
agg.
aggregate
BCIS
Building Cost Information Service
BS
British Standard
CAWS
Common Arrangement of Work Sections
c/c
centres
ddt
deduct
dia.
diameter
d.p.c.
damp‐proof course
d.p.m.
damp‐proof membrane
EDI
electronic data interchange
e.w.s.
earth work support
ex
out of
hw.
hardwood
JCT
Joint Contracts Tribunal
n.t.s.
not to scale
PC
prime cost
MC
Measurement Code
n.e.
not exceeding
NRM
New Rules of Measurement
r.c.
reinforced concrete
RIBA
Royal Institute of British Architects
RICS
Royal Institution of Chartered Surveyors
r.w.p.
rainwater pipe
SMM
Standard Method of Measurement
sw.
softwood
swg
standard wire gauge
About the Companion Website
The companion website for this book is at
www.wiley.com/go/lee/elements-of-quantity-surveying
The website includes:
PDFs
Videos
Scan this QR code to visit the companion website
Chapter 1Introduction
The modern quantity surveyor
The training and knowledge of the quantity surveyor have enabled the role of the profession to evolve over time into new areas, and the services provided by the modern quantity surveyor now cover all aspects of procurement, contractual, and project cost management. This holds true whether the quantity surveyor works as a consultant or is employed by a contractor or subcontractor. Whilst the importance of this expanded role cannot be emphasised enough, success in carrying it out stems from the traditional ability of the quantity surveyor to measure and value. It is on the aspect of measurement that this book concentrates.
The need for measurement
There is a need for measurement of a proposed construction project at various stages from the feasibility stage through to the final account. This could be in order to establish a budget price, give a pre‐tender estimate, produce contract documents for pricing, provide a contract tender sum, or evaluate the amount to be paid to a contractor. There are many construction or project management activities that require some form of measurement so that appropriate rates can be applied to the quantities and a price or cost established.
The measurement explained in this book is primarily for the production of a bill of quantities as part of the traditional procurement approach to construction. Other procurement approaches move the need for detailed measurement to later stages of the project cycle and away from activity undertaken by the client's team to that of the contractor's team.
The need for rules
The need for rules to be followed when undertaking any measurement becomes clear when costs for past projects are analysed and elemental rates or unit rates are calculated and then applied to the quantities for a proposed project. For greater accuracy in pricing, it is important to be able to rely consistently on what is included in an element or unit, and this helps build a more reliable cost database.
Following the Royal Institute of British Architects (RIBA) 2013 Work Stages, the measurement undertaken at Stage 1 – ‘Preparation’ – needs to be of basic areas or functional units, and the guidelines of the Royal Institute of Chartered Surveyors (RICS) Code of Measuring Practice are commonly followed. This enables comparisons to be made between different schemes and options when assessing the feasibility of a project. When preparing a cost plan, the need to include the same items in each element is important so that costs for that element can be accurately applied. In May 2009, the RICS published the first of its new set of rules for measurement dealing with the order of cost estimates and elemental cost planning. The RIBA work stages and the New Rules of Measurement (NRM) are explained a little further in Chapter 2.
The same need for rules applies when measuring for bills of quantities. If a document is to be used for tender purposes and included in a contract, then the contractor needs to know the basis of the measurement and what is included or excluded from an item to be priced. Historically, standard methods of measurement have been used to provide these rules and are available in various forms worldwide. The RICS NRM – detailed measurement for building works (NRM2) are part of the RICS ‘black book’ guidance for accepted practice in the UK. At post‐contract stages, when measuring for variations or additional works, it is important that the rules used in the contract document (if applicable) are followed to minimise disputes.
Establishing the approach
The approach to take for any measurement is to decide its purpose and the level of design detail available, enabling the adoption of the most appropriate rules and procedures.
Having an ability to read and understand the rules for measurement for bills of quantities should enable the measurer to appreciate the requirements of different rules and approaches.
Method of study
Before you start to work through the chapters on each element it is advised to study Chapters 1–7 in order to grasp the basic principles thoroughly. You should understand the form in which dimensions are usually written, irrespective of whether a computer system will eventually be used to record dimensions in practice.
Knowledge of elementary building construction and simple mensuration and trigonometry is assumed; where knowledge is weak in these subjects, further study is recommended before proceeding further with measurement.
Chapter 5 explains some of the alternative systems that are used in practice, and Chapter 6 explains how girths and centre lines are calculated.
Chapter 7 contains notes on general procedure rules for taking‐off which should be read before attempting to study actual examples of measurement, and to which subsequent referral may also be useful.
Chapters 8–18 represent the sections into which the taking‐off of a small building might be divided, and these should be worked through one at a time. The principal applicable clauses of NRM2 are referred to in each chapter and should be studied concurrently. After the chapter has been read, the examples should be worked through. It should be possible to follow every measurement by reference to the drawing. It may therefore be appropriate for you to copy or print off the drawings so that they can be read alongside the dimensions.
The examples of taking‐off in this book are small isolated parts of what could be the dimensions of a complete building and are not a connected series. When they have been mastered in their isolation, it will be much easier to see how they might be expanded and fitted together to compile a bill of quantities for a complete building.
Chapters 19 and 20 deal with preliminaries and bill preparation, which are more logically dealt with after taking‐off, as this is often a separate process.
Examples
The measurement examples are included to illustrate the measurement of individual elements of a small building. They assume that full specification clauses would be set out in preambles to the bill and are not included here (see Chapter 20).
The dimensions that are set down in the dimension column when taking‐off are given to the nearest two decimal places of a metre. Side casts (or waste calculations, as they are sometimes called) are used to calculate these dimensions, and are given in millimetres to ensure accuracy.
The examples in the chapters are presented in a traditional dimension format, this being considered the best system for a textbook and what the candidate will usually be faced with in the examination room. Abbreviations have been used for deductions where a description sufficient to recognise an item clearly is all that is required. The abbreviations used in the descriptions are listed in the ‘Abbreviations’ section at the beginning of this book.
There is a companion website for this book where some of the examples are included as audio presentations to provide further explanation if required.
Chapter 2Detailed Measurement
Method of analysing cost
It is evident that if a building is divided up into its constituent parts, and the cost of each part can be estimated, an estimate can be compiled for the whole work. It was found in practice that by making a ‘schedule’ setting out the quantity of each item of work for a project, the labour and material requirements for these could be more readily assessed. This schedule at Royal Institute of British Architects (RIBA) stage 5 can be in the form of a bill of quantities which, when priced by a contractor, provides a tender sum for a project. It must not be forgotten that a traditional bill of quantities only produces an estimate. It is prepared and priced before the erection of the building and gives the contractor's estimated cost. Such an estimated cost, however, under the most commonly used construction contracts, becomes a tender and a definite price for which the contractor agrees to carry out the work as set out in the bill. The bill must, therefore, completely represent the proposed work so that a serious discrepancy between actual and estimated cost does not arise.
Origin of the bill of quantities
Competitive tendering is one of the basic principles of most classes of business, and if competitors are given comprehensive details of the requirements it should be fair to all concerned. However, historically when tendering based on drawings and specification, builders found that considerable work was involved in making detailed calculations and measurements to form the basis for a tender. They realised that by getting together and employing one person to make these calculations and measurements for them all, a considerable saving would be made in their overhead charges. They began to arrange for this to be done, each including the surveyor's fee for preparing the bill of quantities in their tender, and the successful competitor paying. Each competing builder was provided with the same bill of quantities which could then be priced in a comparatively short space of time. It was not long before this situation was realised by the architect and employer. Here the employer was paying indirectly for the quantity surveyor through the builder, whereas the surveyor could be used as a consultant if a direct appointment was made. This would give the employer greater control over the amount paid to the surveyor and the opportunity to increase the service that was provided. In this way, the quantity surveyor began to get the authority of the employer and was employed to prepare a bill of quantities for tendering purposes.
The measurement process
The main purpose of a bill of quantities is therefore for tendering. Each contractor tendering for a project is able to price the work on exactly the same information with a minimum of effort. This gives rise to the fairest type of competition.
Despite the decline in the use of bills of quantities, over 50% of the value of all building work in the UK is still let using lump‐sum contracts with firm or approximate quantities, therefore requiring measurement. Most other procurement routes, such as design and build and management contracting in its various forms, also involve quantification of the work in some form or other by the main contractor, subcontractor or package contractor, and therefore the measurement process continues to be of importance.
Computerised and other alternative measurement systems have become more widely used. However, it is only by having a detailed understanding of the traditional method of setting down dimensions and framing descriptions that such systems can be fully understood and properly utilised. There continues to be development of 3D computer‐aided design software that integrates with building information modelling, and the ability to generate quantities directly from the computer model. These software programs, however, have difficulty in producing quantities in accordance with any standard method and as yet have not removed the need for the quantity surveyor to check and validate the model, the quantities it generates, and to prepare the tender and contract documents.
Attributes of a quantity surveyor
What, then, are the desired measurement skills of a good quantity surveyor? An ability to describe clearly, fully and precisely the requirements of the designers and present the bill of quantities so that the contractor's estimator can quickly, easily and accurately arrive at the estimated cost of the work is essential. This being so, it is obviously important that the surveyor should be able to write clearly in language that will not be misunderstood, and have a sound knowledge of building materials and construction and of customs prevailing in the industry. Moreover, the surveyor must be careful and accurate in making calculations, have a systematic and orderly mind and be able to visualise the drawings and details.
Divisions of bill preparation
The traditional preparation of a bill of quantities divides itself into two distinct stages:
The measurement of the dimensions and the compilation of the descriptions from the drawings and specification. This process is commonly known as
taking‐off
.
The preparation of the bill. This involves the calculation of volumes, areas, etc. (
extending or squaring the dimensions
). Traditionally, this was followed by entering the descriptions and the squared dimensions on an abstract (
abstracting
) to collect similar items together and present them in a recognised bill order. From this abstract, the draft bill was written (
billing
).
Through the utilisation of computerised systems, the various stages have become more integrated. The facility now exists for direct input of quantities and formulation of descriptions through the use of standard libraries of descriptions, and the lengthy collating and bill preparation processes are carried out automatically. It should be noted that there is often still the need to produce preliminaries and preambles separately and to input uncommon items (rogue
