Bill Of Quantities in Construction: Everything You Need To Know


Bill of quantities (BOQ) is a critical construction planning document that categorizes and details the materials and other cost items necessary to complete a construction project. BOQs provide a detailed description of the cost elements, connecting all stakeholders involved, such as contractors, consultants, and owners.

BOQs can be prepared singularly or as part of work packages, to fully reflect the scope of work necessary for development. They aid in better project planning and cost savings, while setting the right framework for strategic construction development.

Introduction to Bill of Quantities (BOQ)
Bill of quantities in construction projects are prepared during the planning and estimation stages, to provide a complete financial purview of the various elements involved in completing construction work. Preliminaries, measured work, and overheads are captured within the BOQ, along with associated quantities, units, and rates, to provide a concrete pathway towards construction site development.

BOQ in civil, structural, architectural, etc. works can be prepared for different components of site work, based on the scope of the overall project. BOQs also ensure that tendering contractors provide pricing options for the same quantities and specifications of materials, thereby enabling a balanced comparison for procurement.

Key benefits of construction BOQs
Here are some of the important benefits of construction BOQs.

  • A major benefit of designing a highly detailed BOQ is the ability to fully understand the financial scope of each project.
  • With line items listed accurately within BOQs, project owners can gain greater clarity of the material consumption for the project.
  • BOQs are used to illuminate and standardize tendering processes, giving greater information to stakeholders for different types of construction work.
  • Highly refined BOQs eliminate any guesswork required to estimate the scope of work involved, as they highlight every item with its associated costs transparently. The document can be referenced by all stakeholders enabling better planning and scheduling of construction work.
  • Prices within the material categories can be compared, to find the best rates for timely project work completion.

Best practices in developing BOQs
Standardization and accuracy are critical to preparing high-quality BOQs, as the document is referenced widely during the planning stages. Let us look at the best practices when preparing quality BOQs for construction projects.

  • It is important to develop BOQs through a standardized and detailed format that effectively captures form of tender, key requirements, pricing schedule, provisional sums, day works, etc.
  • Key project stages should be correctly mapped and categorized within the BOQ, with correct calculations of BOQ elements closely reflecting approved designs and specifications.
  • BOQs should be prepared with a high degree of accuracy to precisely represent practical construction costs, thereby decreasing risks of overruns and delays.
  • As BOQs are vital to procurement, it is important to research and input the most updated material rates, standards, and units.
  • Teams should leverage predefined bill of quantities templates to standardize BOQ development, thereby minimizing errors and increasing accuracy.
  • Firms should integrate cost estimation and BOQ softwares to streamline their cost planning process.

Preparing bills of quantities for construction work
BOQs can be prepared effectively by framing 5 key components accurately, namely item description, unit, quantity, rate, and total sum. Itemizing the BOQ by grouping per construction stages (earthwork, concrete work, reinforcement, finishing, etc). is an ideal approach for complex projects.

Stakeholders can analyse the quantity requirements, by studying the designs and specifications for the construction project closely. The description of construction work can be listed to provide clarity on the type of work being performed. Users need to calculate the appropriate amounts of materials necessary based on the category of materials listed.

For RCC works, quantities can be calculated by weight and volume. Cement quantities can be calculated as per their volumes required, in terms of complete cement cubic meter needed. The number of bags of cements can be extracted from the calculation, by dividing the volume of 1 cement bag (0.0347 m3).

Steel requirements can be estimated as a fixed percentage of concrete volume (0.5 – 2.5% e.g.), based on the type of construction work being performed. Based on the type of materials listed, the associated labour days will be captured as well. E.g., masons – 0.37 days, unskilled labourers – 3.5 days, etc. can be included while being multiplied by their day rate to derive a final total. Sundry charges will be included as well, depending on the type of construction work executed.

In conclusion
Developers often prepare bill of quantities, meaning the planning document highlighting the various cost elements involved in the completion of site work. While BOQs are essential to effective planning and execution, they are also instrumental to cost management. With the construction industry shifting towards digitized BOQ preparation and management, users are leveraging the best platforms available to manage estimation and BOQs. BuildSupply Estimation Manager enables faster BOQ preparation (up to 50% quicker), while empowering users to gain complete control over cost evolution from concept to detailed design stages.

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