Preparing a bill of quantities requires expertise and diligence. It involves meticulous measurement and costing, which minimizes miscalculations that can lead to budget overruns. It also helps owners control costs and track progress on construction projects.
It’s usually prepared during the tendering process before breaking ground. It’s often based on standard work breakdown structures and is most useful when it’s organized by sub-contract packages.
The purpose of the bill of quantities
Essentially, the bill of quantities is a list of all the materials and construction work required to complete a project. This is usually prepared by a Quantity Surveyor from the architect’s plans. It is then broken down into individual items with descriptions, units of measurement and costs. This is also known as a Provisional Bill of Quantities (PBoQ) because most details are approximated and can be re-measured during the construction process. Typically, a BoQ includes a contingency sum which accounts for unforeseeable costs that may arise during the project.
It is then used by contractors to price the work. This helps to ensure that all tenderers are quoting the same labour and materials. It also allows for a more accurate comparison between proposals and enables the contractor to select the most competitive price.
In addition, the meticulous documentation within a bill of quantities, spanning from material specifications to labour hours, promotes transparency throughout the entire construction process. This can help mitigate disputes and claims, while also cultivating a culture of trust between the contractor and client.
Additionally, the use of a BoQ can be helpful in budgeting and cost control during post-tender works. This is particularly true if the BoQ is separated into work sections that reflect likely subcontract packages. It can also assist with valuation of variations and the preparation of interim payments.
The process of preparing a bill of quantities
A bill of quantities (BOQ) is an important tool used in the construction industry to estimate costs, reduce disputes and claims and improve project delivery. Its preparation involves a number of steps. These include obtaining the design team’s drawings and specifications, performing ‘taking off’ and preparing a list of items to be included in the tender package.
A BoQ is usually prepared by a quantity surveyor or cost consultant and includes a detailed breakdown of the work to be done. It contains items, rates and quantities to be used in the contract, including the cost of labour, equipment and materials. It also includes a percentage to cover overheads and profit. Depending on the type of contract and the market, this may vary from 2.5 to over 25 percent.
Preparing a BoQ requires knowledge of construction processes and a good understanding of current construction rates. It is best to prepare a BoQ in work sections that reflect likely sub-contract packages, as this will help the supplier obtain accurate prices from subcontractors. It is also useful to check local hardware stores for pricing information and speak with contractors who have worked on similar projects to find out their labor rates.
An effective BoQ allows contractors to submit competitive bids for the construction work. It also facilitates the preparation of payment applications as the work progresses. In addition, it can be used to monitor budgets and forecast cash flow requirements.
The benefits of preparing a bill of quantities
Preparing a bill of quantities is an essential part of the construction process. It ensures accurate cost estimates, minimises disputes and claims, and improves project delivery. In addition, it facilitates standardised and equitable tendering, allowing contractors to price on precisely the same details. This reduces misunderstandings and misinterpretations and offers complete transparency around scope and pricing.
Typically, a BoQ is prepared by an experienced quantity surveyor and contains a detailed breakdown of materials, equipment, and labour requirements. The list also includes unit prices for each item and any supplementary costs like overheads and profit.
There are several different types of BoQs, each with its own purpose and level of accuracy. These include:
An Itemised BoQ is the most precise type of BoQ, offering the highest level of accuracy. It includes a detailed breakdown of all required materials and equipment, with exact quantities specified for each item. It is normally created at the end of the design stage as the basis for contractor bidding and project delivery.
A trade BoQ organises the scope and pricing of a project by trades like electrical, plumbing, framing, and masonry for easy bidding by subcontractors. A location BoQ divides the project into zones or areas like 1st floor, East Wing, and so on, with a detailed breakdown of items by area. This helps the quantity surveyor to calculate the work effort and rates for each area.
The risks of preparing a bill of quantities
Preparing a bill of quantities is time-consuming, and any miscalculations can lead to budget overruns and delay project timelines. The primary purpose of a BoQ is to manage cost and deliver the project on time, which requires precision. It is therefore essential to devote adequate resources and expertise to the preparation of a BoQ.
Typically, quantity surveyors prepare BoQs based on the project specifications, architectural drawings, and other related documents. They can also work with design professionals to understand the requirements and scope of the project. A BoQ should be as comprehensive as possible, which can include the following:
A BoQ enables contractors to submit competitive bids by providing a detailed breakdown of labor and materials. This allows owners to compare the proposals of different bidders and choose the best one. It is also a useful tool for monitoring progress during construction, determining progress payments, and evaluating variations.
The process of preparing a BoQ involves many steps, including obtaining the design team’s drawings and specifications, conducting takeoffs, and calculating material and labor costs. It is important to verify the accuracy of these estimates by checking prices at local hardware stores and speaking with contractors about their labor rates. A BoQ should also incorporate a contingency sum to account for unforeseeable expenses. This will ensure that the contractor does not overspend and stays within budget.