All about quantity surveying bills of quantities production

This article is all about quantity surveying bills of quantities and their production

Introduction

This article is all about the production of bills of quantities in the construction industry.

Bills of quantities are documents that contain a description of all the construction work that must be completed in a construction project and includes detailed descriptions of that work and the quantity of the work that must be completed.

Purpose of the bill of quantities

The purpose of a bill of quantities is to provide a complete list of quantities and descriptions of the work in a building project. Simple as that.

In every construction project someone has to definitely quantity the scope of work in each work package. Someone has to do the work onsite. So for example the concrete contractor needs to know how much concrete and what specification concrete he needs to order for delivery the following week. The electrician needs to know how many power sockets and switches he needs to order for installation. Building projects exist on lists of quantities. These quantities can be calculated by the sub-contractors, the main contractors or the Clients quantity surveyor. In fairness, all of these parties should be doing their own take-offs to ensure they know exactly what they are doing. For example, an electrician should be doing their own count of sockets before ordering instead of ordering off the Clients quantity surveyors bill of quantities.

A bill of quantities is a complete list of all the work required in a construction product expressed in a logical sequence and outlining the quantities and full description of each item of work.

Benefits of bill of quantities

There are multiple benefits to a bill of quantities:

• At tender stage this list or bill allows the Client to receive competitive prices from several contractors with the comfort of knowing they are pricing the exact same works. The tenders can be then compared and any differences will highlight any issues that otherwise might not have been picked up
• Post contract, The bill allows easy valuation and payment of works completed to date through interim progress payments
• It also allows easy valuation of variations because there are already rates in the BOQ for the works that are being changed
• Finally, a fully priced bill of quantities provides detailed historical cost information which can be used to price further projects. It is essentially a very accurate cost model for this building type.

If you talk to any quantity surveyor, they will tell you that using a bill of quantities is the traditional and best way to get a lump sum, fixed price for a building project. It has proven itself time and time again to lower the risk of post contract cost fluctuation.

The types of bill of quantities (BQ)

A bill of quantities can be firm or approximate.

Firm Bill of Quantities

A firm bill of quantities is a bill with full quantities that is used to obtain a fixed lump sum price from a contractor. There is no remeasurement of the works.

If a contractor signs a contract using a firm bill of quantities, their final cost (in the unlikely event there are no variations) should be the amount they included in the BOQ.

Of course, every construction project has changes (that is just life) and so the BOQ can be used to price any additions or indeed omissions

Approximate bill of quantities

An approximate bill of quantities has quantities which are re-measurable contract as the works progress onsite.

It used when there is not enough information on the project for a detailed bill of quantities and therefore approximate quantities are used.

Of course, if the contractor starts onsite with a bill of approximate quantities, there is going to ongoing measurement for every trade every month. This is an administrative nightmare as it is a lot of work agreeing quantities and costs. Also, the Client can never be given accurate cost advice as the final cost is always subject to change.

It begs the question why a Client would start a construction project when they are unsure of the amount of work required. A diligent quantity surveyor should advise on waiting for the design to be developed further to allow the creation of a property bill of quantities or recommend a suitable procurement process such as two-stage tendering.

Who prepares the Bill of Quantities?

In a traditional procurement process the employers quantity surveyor/cost manager prepares the bill of quantities.

When using design and build, the employers quantity surveyor/cost manager prepares the employers requirements and then the contractor prepares the bill of quantities or detailed schedule of work with rates.

Guidance on the preparation and composition of BQ

Bill of quantities (BOQ) consists of the following sections:

1. Form of Tender
2. Certificate of bona fide tender
3. Main Summary
4. Preliminaries, comprising two sections, Information and requirements and Pricing schedule
5. Measured work (incorporating contractor designed works)
6. Risks
7. Provisional sums
8. Credits (for materials arising from the works)
9. Dayworks (Provisional)
10. Overhead and profit
11. Fluctuations
12. Annexes

Some of these sections can be omitted if not required.

See the main summary items for further explanation of what goes into a bill of quantities.

What is the form of tender in a bill of quantities ?

This is a document that is used to record the main contractor’s price for completing the building project (i.e. his tender price).

If accepted by the employer, the tender price will become the ‘contract sum’. The form of tender can be a separate document.

A separate ‘certificate of bona fide tender’, which is completed by the main contractor to confirm that he has not communicated his tender to other parties, is sometimes inserted after the form of
tender.

Alternatively, the employer’s requirements for confirming that bona fide tender has been submitted by the main contractor can be incorporated in the form of tender.

What is the main summary in a bill of quantities ?

Where the measured work has been divided into work sections, the work sections will be listed instead of elements.

At the end of the summary, provision is made to total the list to ascertain the total price and

transfer the total to the form of tender, which, subject to verification and any necessary

adjustments, will become the contract sum referred to by the conditions of contract.

The main summary is the main collection page of the bill of quantities. It can be at the front or end of the bill.

This summary will include headings such as:

Preliminaries (Information and requirements and Pricing schedule)

Measured works (including ‘Contractor Designed Works’

• Facilitating works
• Substructure
• Superstructure
• Internal finishes
• Fittings, furnishings and equipment
• Services
• Complete buildings
• Works to existing buildings
• External works

Risks
Provisional sums

• Defined
• Undefined

Works to be carried out by statutory undertakers
Overheads and profit
Credits (for materials arising from the works)
Fixed price adjustment
Director’s adjustment
Dayworks (Provisional)
Total price (to Form of Tender)

The contractors who price the bill of quantities will total the individual sections and ‘carry forward’ these totals to the main summary.

Then all of the separate carried forwards figures are totaled and this final total is sent to the form of tender.

What are Preliminaries in a bill of quantities ?

Preliminaries is simply the name given to the group of costs that the contractor will incur that are not directly rated to the construction works.

For example, Preliminaries are not the materials, labour and tools used in the works. They are not the insulation, timber floors, glues that are used in flooring. All of these costs are included in the measured works part of the bill of quantities.

Instead they are the costs associated with just being onsite.

In a bill of quantities the preliminaries section is split into 1) Information and requirements and 2) Pricing schedule

Information and requirements include information on the following particulars of the building project:

• management of the building project
• site establishment
• security
• safety
• environmental protection
• common user mechanical plant
• employer’s completion and post-completion requirements
• the drawings upon which the bill of quantities was based
• the work in general
• the site and any adjoining properties
• the form of contract and any amendments and/or supplementary
  conditions to the form of contract
• the employer’s specific requirements; and any specific limitations or restrictions that might impact on the sequence and/or method of working
• information on how to interpret the bill of quantities, including any special methods of
  measurement (i.e. where the method of measurement has deviated from NRM 2: Detailed
  measurement for building works).

These particulars are then priced in the pricing schedule which we examine below.

What is a Pricing schedule in a bill of quantities ?

The Pricing schedule (for the preliminaries) in a bill of quantities is the part of the preliminaries document where the contractor can insert their costs for the employers requirements as previously described in the bill of quantities.

Its just a simple schedule which the contractor can fill in their costs.

• employer’s requirements
• contractor cost items
• management and staff
• site accommodation
• services and facilities
• mechanical plant
• Temporary works items

What is Measured work in a bill of quantities ?

This section of the bill of quantities is simply the main body of the bill of quantities. It provides all the works required to be completed including detailed descriptions and quantities.

The quantities should be measured in accordance with Part 2 of the NRM2.

Various methods can be used to present the quantities as shown on paragraph ‘A.1 at Appendix A: Guidance on the preparation of bill of quantities’ of the NRM2.

The measured works can be presented in elements or by work sections.

What are non measured work in a bill of quantities ?

Non measured work is covered in the preliminaries section and in the provisional sums section

What are annexes in a bill of quantities ?

Annexes included information that is referred to in the specification where it is not contained or issued as a separate document e.g. the specification.

Examples include:

• Performance specifications
• Copies of quotations
• Copies of communications with statutory undertakers.

What are provisional sums in a bill of quantities ?

Provisional sums are sums of money included for works that are anticipated but which cannot be costed yet due to the fact the design has not yet been developed yet or the Client has not chosen a product yet.

This could also include works by a statutory undertaker which rarely if ever give fixed costs for their works until it is time to book them in e.g. utility contractors such as water, electricity, gas.

The works are foreseen but they cannot be accurately measured or costed. Therefore reasonable amounts of money are allowed for these items by the quantity surveyor/cost manager to cover these costs. The provisional sums should be more than enough to cover these costs.

Post-contract there should be a saving against these provisional sums not an additional cost. Otherwise the quantity surveyor/cost manager has simply not allowed enough money.

What are Risks in a bill of quantities ?

Residual risks are risks that the Client cannot simply avoid or contract their way out of.

They are risks which are not definable and therefore cannot be passed onto a sub-contractor.

One example is the risk of the soil in the site being contaminated. Even if the soil is tested, there is still a risk that once excavation starts the contractor will find contaminated soil.

This part of the bill of quantities allows the Client to competitively tender the cost of taking, managing and dealing with this risk should it materialise post-contract.

What are dayworks in a bill of quantities ?

Dayworks is the section in a bill of quantities where the Client gives the opportunity for contractor to price works that might be carried out on a dayworks basis.

A schedule of sample daywork rates e.g. plumber per hour is given and the contractor must provide a price.

When works are instructed to be carried out on dayworks then the contractor must use these rates.

By including these rates within the bill of quantities it allows these rates to be competitively tendered.

What are Credits (for materials arising from the works) in a bills of quantity ?

This part of the bill of quantities allows contractors to provide competitive pricing for the credit they will give for materials arising from the works.

Say for example there is a lot of copper in the building to be demolished, the Client will be looking for a credit for this copper that they can offset back against the cost of the build.

Methods of bill of quantities production

The traditional method of creating a bill of quantities is the ‘taking off, abstracting and billing method’.

However, this method was deemed to take too long and to be incredibly inefficient requiring large numbers of skilled staff. We only mention now because of its historic significance and because all modern methods of bill production originate from it.

This method was replaced by the cut and shuffle method which in turn was replaced by computer software.

In the present age, a bill of quantities can be produced relatively quickly. A quantity surveyor can open a simple software application and take-off (measure quantities) from the drawings using the computer. These quantities can then be automatically filled into the respective part of the standard bill of quantities template. This reduces the number of steps in the production of the bill and also eliminates the need for checking and rechecking calculations.

The traditional Working up process for bill of quantities production

Working up is the traditional term given to the set of actions involved in the production of a bill of quantities. It consists of two main stages of abstracting and billing.

Assuming you have completed the taking off (measuring) of quantities, the process involves:

1- Squaring all of the dimensions from your dimensions sheets (e.g. multiplying, deducting etc)

2-Entering all of the resultant lengths, areas, volumes  into the squaring column

3-Transferring the squared figures to the abstract in a pre-determined, set, formal , recognised order

4-All of the items of work which must be completed are listed out under the appropriate work section headings with descriptions printed in full along with the quantities (from the abstract) given in the recognised units of billing.

The end result is a detailed bill of quantities with full quantities.

Notes on working up

The bill of quantities has the description of the works, the quantity and also the rate and price columns for pricing by the contractors.

The Direct billing process for bill of quantities production

This method is similar to the working up process but instead of transferring the squared dimensions to an abstract page, you simple transfer the quantities to the bill of quantities page.

What does a bill of quantities page look like ?

The ruling of bill of quantities pages look generally the same anywhere you find a bill of quantities. They have evolved from the now defunct british standard specification ‘Stationary for quantity surveying’ BS3327: 1970).

The purpose of this standard was to give a uniform standardised method of setting out a bill of quantities.

Each page is a4, portrait landscape. There are several columns starting from left to right:

Column – meaning

1 – Item nr. or reference

2 – Description

3 – Quantity

4 – Unit

5 – Rate (£)

6 – £

7 – p

For example:

Item 1 – New timber flooring – 100 – m2 – £85.00 – £8,500.00

Units of measurement in a bills of quantities

The units of measurement in a bills of quantities are:

• Linear metres e.g. 100 m of skirting
• Square metres e.g. 100 m2 of flooring
• Cubic metres e.g. 100 m3 of concrete
• Tonnes e.g. 100 t of steel
• Enumerated items  e.g 100 nr doors