Choosing Wisely: Bills of Quantities or a Schedule of Work – What’s Right for Your Project?

Author: Bart Kolosowski
Published: July 4, 2023

Choosing Wisely: Bills of Quantities or a Schedule of Work – What’s Right for Your Project?

The subject of this article has been suggested by Susan Price, Director of BB Partnership Chartered Architects. Thank you, Susan, sometimes the most difficult part of creating this content is to come up with subjects.

Introduction

Proper documentation is the lifeblood of construction projects. It provides a concrete roadmap that guides every stage of the construction process, from initial planning to final handover. Among the array of documents used, two types stand out for their critical roles in ensuring smooth project execution: the Bill of Quantities (BoQ) and the Schedule of Works (SoW).

While they may seem similar, BoQ and SoW each serve unique purposes and are best suited to specific types of projects. This article aims to help you discern these differences and choose wisely between a BoQ and a SoW for your particular project needs.

We will delve into the distinct characteristics of both BoQ and SoW, highlighting the components, functionality, and suitable project types for each. We will also impart best practices for creating an effective SoW and underscore the invaluable role of a Quantity Surveyor in the preparation and use of these documents.

Expect a comprehensive exploration of these two vital tools in construction project management. By understanding their unique features, strengths, and limitations, you can make an informed decision that best serves your project.

So, are you ready to uncover the distinguishing features of BoQ and SoW and decide which fits your project like a glove? Let’s begin.

Understanding Bills of Quantities (BoQ)

What is a Bill of Quantities (BoQ)?

A Bill of Quantities (BoQ) is a document used in the construction industry to provide an estimated, itemised list of activities, items of work and other costs required to complete a project. By using a BoQ contractor can further establish all materials, parts, and labour required for a construction project. It forms an integral part of a formal contract and acts as a basis for cost-control and monitoring mechanisms during project implementation. A BoQ contains several crucial components, among them: preliminaries, measured works, and provisional sums.

The Structure and Components of BoQ

The structure of a BoQ reflects the complexities of the project at hand. One of the primary bills is ‘measured works’, which contains detailed descriptions and quantities of the work to be performed. This bill is typically divided further into sections reflecting different trades or stages of work, such as groundwork, structural works, finishes, external works, etc. The structure is governed by the standard method of measurement used for the project.

The ‘preliminaries’ bill or section, on the other hand, covers general project expenses. It includes elements like site setup costs, management fees, temporary works, and professional fees.

The ‘provisional sums’ component provides an allowance for works that cannot be entirely defined, quantified, or priced at the time of tendering. This could be due to factors such as design development or unpredictable elements of the project.

A BoQ may also include other bills and sections as necessary, this may be a list of daywork rates or client direct packages of work, or other items specific to the project.

The Role of Standard Methods of Measurement (SMM) in BoQ

Standard Methods of Measurement (SMM) play a significant role in creating a BoQ. SMM provides a uniform format for measuring construction works, ensuring the BoQ is universally understood by all parties involved in the project. The current SMM standard used in the UK is the New Rules of Measurement 2 (NRM2), introduced in 2013, offering a more comprehensive approach to capturing and structuring project costs compared to its predecessor, the SMM7. However, some UK-based price books, such as BCIS, still employ the even earlier SMM6 standard. Internationally, there are other SMMs used for cost control, such as CSI in the USA, ASMM in Australia, POMI (developed by RICS) widely used in the Gulf.

The Applicability of BoQs

BoQs are particularly effective for large and complex projects where detailed specification of activities and costs is necessary to control pricing and cost change control. They also prove beneficial for contractors with in-house Quantity Surveyors and professional teams who can effectively interpret and utilise the BoQ to prepare subcontractors’ and suppliers’ packages and enquiries, control costs and manage the project efficiently.

However, a BoQ might not always be the best fit. For instance, in projects not fully designed yet or for smaller schemes where contractors might struggle to engage with the detailed nature of BoQs, an alternative like a Schedule of Works might be more suitable.

This understanding of BoQs will allow us to appreciate its comparison with Schedules of Work in the following sections.

Understanding Schedule of Works (SoW)

What is a Schedule of Works (SoW)?

A Schedule of Works (SoW), as it pertains to construction projects, is a document that outlines the work that needs to be completed in a given project. Unlike a Bill of Quantities (BoQ), a SoW typically provides an overview of the works without delving into the nitty-gritty of every task. It gives a broader picture, providing just enough detail to make sense of the project’s overall needs.

The structure of a SoW can vary significantly. Depending on the writer or the project’s unique requirements, it might be a concise one-page document with broad descriptions or a more extensive multi-section document approaching the detail level of a BoQ. There is no universally accepted structure for a SoW, as it is not guided by a standard method of measurement like a BoQ.

The Structure and Components of SoW

A Schedule of Works comprises different components, including descriptions of work, quantities, and sometimes units of measurement. These components are often bundled together as an ‘item’, which stands for a particular work activity or a group of closely related tasks. For instance, an item in a SoW might cover all the works related to roofing, including the structure, insulation, and covering.

Contrasting this with a BoQ, which breaks down the works into minute details, a SoW tends to clump together multiple tasks into one priced item. This makes it less comprehensive but arguably more accessible for certain types of projects and contractors.

The Function of SoW in a Construction Project

A Schedule of Works serves multiple purposes within a construction project. It outlines the sequence of works, helping the project team understand the order in which tasks should be completed. It also spells out the contractor’s responsibilities in broad terms, without going into the detailed specifications found in a BoQ.

In terms of project management, a SoW is used to coordinate tasks, schedule resources, and assess interim payments. It offers a high-level understanding of cost allocation, making it a useful tool for cost management. With its less detailed nature, a SoW is a more limited basis for assessing variations, as the cost detail is often insufficient to discern the cost implications of each change in the works.

The Applicability of SoWs

Schedules of Works are typically used for smaller or less complex projects. Their less detailed nature makes them more manageable for smaller contractors who may lack the skills or resources to deal with the complexity of a BoQ.

On the other hand, for larger and more complex projects requiring a detailed breakdown of works and costs, a BoQ might be more suitable. It’s crucial to choose the right document for the project’s specific needs, as this decision can significantly impact project management and financial control.

Using a SoW comes with its challenges. Due to its broad descriptions, it might not cover all eventualities, leading to ambiguities or disputes during the project execution. To mitigate these issues, it’s important to ensure that the SoW is as clear and comprehensive as possible, considering the project’s scale and complexity.

Best Practices for SoW Writing

As we have explored, a Schedule of Works (SoW) is a highly versatile tool, particularly suited to less complex projects. However, the effectiveness of a SoW largely depends on how well it is written. The key to a successful SoW is clarity and detail, providing enough information to eliminate ambiguity without overwhelming with unnecessary complexities. In this section, we’ll provide practical guidance on crafting an effective SoW, building on the insights shared in the previous section.

The Structure of a Clear SoW

A SoW should have a clear, well-organised structure that mirrors the actual workflow of the project or the involvement of different trades. This approach simplifies the understanding of the work sequence, reduces the potential for misunderstandings, and facilitates smoother project execution. For instance, a SoW for a residential building project might be organised into sections like groundworks, brickwork, roofing, and interior finishing, reflecting the sequence of tasks.

Aligning SoW with Drawings and Specifications

Consistency across project documentation is crucial for preventing conflicts during project delivery. Your SoW must align with the project drawings and specifications. If these documents contradict each other, it may lead to confusion, incorrect pricing, and disputes during construction. For instance, if the SoW states “install kitchen cabinets,” but the specifications and drawings detail a bespoke, hand-made kitchen, this discrepancy could lead to significant issues.

Avoiding Duplication and Overlap

In a SoW, each task should only be described and priced once to prevent confusion and potential disputes. It’s crucial to avoid duplicated descriptions or overlapping items/sections. For instance, if plastering work is included in both the ‘internal walls’ and ‘finishes’ sections, it might result in double-pricing or misunderstandings about who is responsible for the task.

Comprehensive Item Descriptions

Each item in a SoW should have a detailed description to provide clarity on what is included in the cost of that task. Going back to the example of a roofing task, the description should include a full specification of structure, insulation, covering, and any other relevant components. This approach leaves no room for ambiguity and ensures everyone understands the scope of work.

The Impact of Clear SoW Writing on Project Delivery

Adopting these best practices for SoW writing brings about numerous benefits. It removes ambiguities, aids contractors in providing accurate pricing, and reduces the likelihood of variations during project delivery. A well-written SoW sets the groundwork for effective project management and financial control, and ultimately leads to a satisfied client. By giving due attention to the SoW writing process, you set the project up for a smoother execution and successful completion.

The Client’s Perspective

The choice between a Bill of Quantities (BoQ) and a Schedule of Works (SoW) is not only crucial to the construction team’s operations, but it also significantly impacts the client’s understanding and experience of the project. It directly influences how informed the client feels, their level of engagement with the project, and the degree of control they perceive they have over the project’s progression.

Understanding the Project

Firstly, the level of detail provided in either a BoQ or SoW can help the client to grasp the complexity of the construction project. A BoQ, with its comprehensive breakdown of tasks, materials, and costs, gives clients an in-depth understanding of the project’s specifics. This document is especially beneficial for clients who have a technical background or an interest in understanding the granular details of the project.

On the other hand, a SoW offers a high-level overview of the project. It is generally simpler and less detailed, making it more accessible for clients unfamiliar with technical construction terminology or those who prefer an at-a-glance understanding of the project’s direction.

Transparency and Cost Certainty

The choice of document also has implications for transparency and cost certainty. A BoQ offers a more transparent view of the project, breaking down costs and allowing for detailed tracking of expenditures. This level of detail can increase clients’ confidence in the budgeting and cost management of the project.

Conversely, while a SoW provides less granularity in cost breakdown, its more succinct overview still offers a degree of cost certainty. Each task is linked with a cost, enabling clients to see the distribution of the budget across the project’s different elements.

Project Control

From a client’s perspective, the feeling of being ‘in control’ is crucial. A BoQ, with its extensive detail and precise measurements, may give clients a heightened sense of control over the project, as they can track each task’s progress and related costs.

In contrast, a SoW provides a broader view of the project’s progress, offering clients an easier way to understand the overall project flow without the need to delve into the specifics of each task. This level of oversight can be enough for clients who prefer a more general overview rather than a detailed breakdown.

In summary, whether a BoQ or a SoW is more appropriate will depend heavily on the client’s preferences and requirements. Clear communication with the client will ensure the most suitable document is chosen, enhancing their understanding, ensuring transparency, providing cost certainty, and facilitating effective project control.

Conclusion

Navigating through the complexities of construction project documentation is a crucial aspect of managing a successful project. The choice between a Bill of Quantities and a Schedule of Works is not a one-size-fits-all solution, but rather a strategic decision based on multiple factors, including the project’s scope, complexity, and the client’s needs and preferences.

By making an informed choice, construction professionals can ensure effective project management and financial control, contributing to smooth operations and successful project delivery. Looking forward, with the advancements in digital trends and standardisation efforts in the construction industry, the adaptability of these documents will continue to be important. We may see the development of hybrid or new forms of project documentation that further enhance efficiency, transparency, and collaboration.

The construction industry is continually evolving, and so are its tools. Whether you’re a contractor, a project manager, or a client, understanding the strengths and limitations of each document type will allow you to leverage them effectively, leading to more successful construction projects.

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