What is Quantity Take off in Construction?

Quantitative take off are used when data is collected to produce a reliable pricing process and construction cost estimate. Managers of complex construction projects must organize, estimate, and manage their teams of all information related to the physical materials used in the project. The most accurate quantity surveying system provides the realistic estimates you need to efficiently manage your project from concept to completion.

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What Is Quantity Takeoff In The Building Industry

It is relatively easy to explain what Quantitative take off is in construction. A quantity taken off (QTO) refers to the estimate of materials, resources, and labor required to complete a construction project. Review your project plans and get information about the physical materials specified by your architect, engineer or draftsman to build your project.

Quantity takeoffs in construction have many other names, including:

• Estimating takeoffs
• Construction takeoffs
• Earthwork takeoffs
• Material takeoffs
• Material estimating
• Material counts
• Quantity surveying

Regardless of the name, quantity calculations are different for each material. As a general rule, quantity surveyors and ground-up specialists do not consider other project requirements such as labor, overhead, permits, insurance, equipment, and incidental costs. They insist on isolating material requirements and translating that information into cost-based estimates.

The Importance Of Quantity Takeoffs

Quantity take off contributes to an important aspect of cost estimation. The accuracy of quantity calculations is reflected in the overall cost of construction. The importance of quantity calculations is explained below.

Cost Tracking

Accurate quantity calculations make it easier to track construction costs because you have a clear idea of ​​the budget you have to spend. This helps in decision-making and avoids budget overruns. Having the right amount of leverage gives you room for unexpected expenses. Labor, equipment and materials for all construction elements are easily predictable.

Communication

Everything in construction costs money. Customers are always looking for ways to optimize their capital. Accurate cost estimates enhance clear communication that keeps customers informed. This in turn leads to gaining the trust of our customers. Customers can track their projects and expenses.

Winning More Bids

To make sure you get the right quote, you need to thoroughly review your cost estimates and estimate them to get an edge over your competition. A contractor’s consistency in achieving accurate quantities is indicative of their work efficiency, which ultimately leads to winning more tenders. Quantity calculations may seem tedious at first, but when carefully considered, they can be a formula for winning more tenders.

Time Management

Quantity influences the client’s decisions in project budgeting and contractor selection. Choosing a contractor is a tedious process, but if the take-off is done accurately, it can save time spent on corrections. In addition, projects are implemented more seamlessly with fewer delays due to cost overruns.

Types Of Quantity Takeoff

The introduction of technology in the construction industry has revolutionized the way Quantity take off processes are performed. However, this does not negate the human element in take-off. There are two important types of quantity calculations, which are described below. These are manual and digital take offs.

1. Manual Takeoffs

This is the oldest form of harvesting materials. When construction estimators calculate estimates without using cost estimating software, they use manual calculation methods, whether they use an Excel spreadsheet or a Microsoft word processor. At the most basic level, manual estimating involves reviewing the scope of work and specifications shown on drawings and contract documents. The estimator then takes measurements from those documents and determines the exact measurements of the work required to build the structure. The estimator must be able to read the project plan and match it to the specifications. Cost estimators must be careful to avoid omissions in the estimation process.

Pros Of Manual Takeoffs

Although digital take-off has many advantages over manual take-off, there is no mechanical substitute for cost estimation tools. Manual take off has the following advantages:

• Use more insights from cost estimators.
• Used as a proper check for digital take off.

Cons Of Manual Takeoffs

There are some disadvantages to manual take off which are explained below.

• It is slow: The obvious disadvantage of manual take-off is the time lag and time wasted manually entering numbers into the worksheet.
• Reduced accuracy: Accuracy is also reduced compared to digital takeoff.

2. Digital Takeoffs

Although digital take-off using computers and database applications was a relatively new emerging technology, it is now widely used in the construction industry. Digital take-offs are superior to manual take-offs in terms of speed and efficiency. Digital takeoff uses a digitizer, an electronic device that takes measurements from maps and enters the data directly into a computer program. You can scan photos regardless of the size they are placed on. Digital takeoff can be a complex and complicated process

There are several advantages and disadvantages to digital take-off, which are explained below.

Pros Of Digital Takeoffs

• Digital take offs are more accurate than manual take offs. It takes the information directly from the rendered maps and adds a layer of redundancy. This ensures that nothing is missed in the cost estimate.
• Production time is also shorter. This reduces the labor costs associated with performing quantitative takeoffs and allows contractors to pursue other available opportunities. The digital take off time is flawless.
• Digital take offs do not require as much expertise as manual take offs. Manual estimating requires the cost estimator to have experience and knowledge in interpreting plans and drawings. But with digital take-off, all these data are entered into the software. This software has built-in functionality to analyze these maps and perform complex calculations.

Cons Of Digital Takeoffs

Disadvantages of digital take off are:

• The accuracy of this method is directly related to the presented map. With digital take-off, errors can occur when calculations, counts and measurements are incorrect.
• Another drawback is the large size of the maps that need to be scanned. Digitizers are very large and must be able to access information at once.

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What Measurements Are Required? 

Manufacturers create products and then sell them as best they can. For example, there is no need to buy long nails or wooden boxes. Therefore, different materials should be measured in different ways. You don’t count drywall the same way you count doorknobs, and you can’t measure carpet the same way you figure out how many pipes you need.

Unit count

Items such as lights, pipe fittings, hinges, doors and outlets are items that are counted as units. For things like nails, a unit consists of 500 pieces. Units can also be individual objects such as air conditioners or windows. An item may come in different sizes, each of which usually has its own cost. This means that items must be grouped within their size and cost group.

Linear length 

You can count pipes, electrical wiring or steel parts, but suppliers sell them by length. Therefore, we must calculate the quantity by the length of the straight line.

Surface area

To calculate the amount of material covering an area, such as carpet, multiply the length and width of the space to get the surface area. This process is used when removing ceiling values.

Cubic volume

If you’re filling the space with something like concrete or blown-in insulation, you’ll need the length x width x height measurements. This calculation determines the volume of materials and allows you to accurately calculate cost estimates.

Physical weight

Materials such as sand are expressed by measuring weight, such as 1 ton of sand. It is usually purchased in standard quantities, but must be overestimated in order to order a sufficient quantity.

Comprehensive Steps To Conduct A Quantity Takeoff

As with all aspects of infrastructure in building construction, gaining volume is a process. Learning how to take off material is a skill that can potentially be managed if you have the time and resources to learn the system and then hone your skills.

On-the-job training can be expensive. Humans are fallible, and manual takeoffs are especially prone to misunderstandings, omissions, and miscalculations. The same applies to digital take-off if the source input is wrong or the program operator does not apply the correct principles.

There are two goals to ensure that quantity calculations are correct and meaningful. Deviating from either method can lead to mistakes and make errors worse. Input errors invariably lead to incorrect final calculations, and inappropriate output errors can have an equally negative impact on money, time, and inefficiency.

To perform quantity calculations correctly, you must follow a proven process. This formula has been around for years and is the same whether you use manual or digital take-off methods. There are two parts to the exact quantity calculation:

The Initial Phase: Input Considerations

Proper collection of materials begins with entering accurate information into the plan. Whether designers are still drawing blueprints by hand or CAD operators are creating multi-layered 3D architectural models, engineers are taking off on data management. It begins with computer-aided entry of detailed information into a prototype or take-off software.

The takeoff crew can only control what they are given. A designated estimator typically does not prepare original concepts, actual drawings, or CAD layouts. Other members of the architectural chain typically design and specify the project. However, an astute take-off technician can identify and explain anomalies during data handling. This is an important control at the input stage.

The Final Phase: Output Specifications

Performing material recovery is the core of the output stage of data management. Output transforms concepts into physical entities, and this is where accurate estimation of materials becomes necessary. By outputting specific numbers from the software printout, a solid estimate is created that is the basis for winning the bid.

This is where the individual or team takes control. Errors and omissions aside, bill of materials relies on a system that identifies materials, quantifies them, and attaches the data to the price list. If done correctly, this systematic approach will provide fairly accurate recommendations for moving your project forward.

Construction data management experts receive output material quantities and incorporate this information into schedules based on valid pricing structures. For small projects, estimators may use values ​​based on local suppliers or subcontractors. For large construction proposals, estimators often use internal prices. Takeoff experts know where to look for quality data to use in volume takeoffs.

How To Do A Quantity Takeoff? An Example

Like all other aspects of construction, taking off is a skill that is perfected over time and experience. The take-off formula, whether done digitally or manually, is divided into input and output. You can also do take-offs manually, but mistakes in digital take-offs during the preparation phase can lead to costly mistakes in your project.

Input

To achieve the correct take-off value, the correct data must be entered in the take-off model. Whether you work manually or digitally, it’s important to manage your inputs properly. Software solutions can provide high quality programming solutions.

In most cases, the cost estimator is not responsible for preparing the design or concept of the project and must rely on the data provided. This requires a review of the plan to test the accuracy of the data provided. The software solution also has a model checker with collision detection capability to check model validity.

Output

The output stage transforms the provided data concepts into the physical requirements required for the project. This is where you create estimates and actual numbers to make your project a reality. It is also important to accurately estimate the materials at this stage. This data is used during construction tenders and the more detailed the data, the higher the bid success rate.

The main focus throughout the output stage is identifying materials, quantifying the data and matching it to a pricing system.

Consider the example of taking off on a masonry wall.

1. First, calculate the net wall area in (ft2 or m2) from the construction plan. When calculating the site, openings should be excluded and double counting of corners should be avoided.
2. Next, calculate the surface area of ​​a single brick, including mortar joints.
3. Next, divide the net wall area by the brick area to determine the required bricks for the wall.
4. Then add a discard factor of 2-10%.

The Advantages Of Precise Quantity Takeoffs

Quantity take off has a significant impact on various aspects of a project, from the initial design phase to project execution and construction. Ensuring that quantity calculations are accurate can help ensure maximum project success. Accurate Quantity take off provides an accurate breakdown of material requirements, and Quantity take off of these requirements allows estimators to estimate the cost of incremental project components such as:

• Project estimation: Quantity take off is the basis of project estimation, so the more accurate the quantity is, the more accurate the project estimate is. These estimates allow us to determine whether the project is feasible within budget constraints and whether it can be completed in accordance with the client’s needs and expectations.
• Bidding: Accurate quantity calculations allow construction companies to submit more competitive bids. Accurate calculation of material quantities allows companies to avoid underestimating or underestimating and demonstrate efficiency and professionalism to win winning tenders.
• Budgeting: Accuracy in budgeting is the result of accurate quantity calculations. By accurately counting and calculating the amount of materials needed, construction companies can accurately estimate costs and deliver projects within budget.

Accurate quantity accounting improves the accuracy of project estimating, bidding and budgeting and allows construction companies to:

• Minimize material waste: Accurate quantity calculations determine the exact amount of material needed for a project and help reduce overestimation. When material requirements are accurate, companies can optimize orders to reduce waste and increase profits.
• Improve time management: Starting a project with accurate quantity values ​​reduces project delays and saves time due to insufficient or incorrect material supply. Accurate quantity calculations also simplify project planning and speed up the design and execution phase of the project.
• Prevent costly rework: When quantity takeoffs are based on accurate calculations, companies can ensure accuracy and avoid costly errors throughout the life of the project. Estimators can provide accurate and precise information that prevents rework and promotes project success from the start.
• Enhance collaboration: Clarifying material requirements through accurate quantity calculations allows different teams to effectively coordinate and communicate throughout project design and construction. Clear project estimates facilitate clear communication with clients and increase client satisfaction and loyalty.
• Perform cost tracking: Accurate quantity calculations enable effective cost tracking by providing a clear picture of actual costs required. Support informed decision-making by helping team members forecast costs, reduce budget overruns, and manage unexpected costs.
• Manage documentation: Accurate Quantity take off serves as a valuable foundation for documentation and record keeping. It provides a record of estimated quantities and costs that can be referenced throughout the project to assist with change management, progress evaluation, and post-project analysis.

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What Is Included In A Quantity Takeoff?

Quantity take off is a mathematical exercise. I need to extract the values ​​and numbers from the input side of the calculation and expand the values ​​on the output side of the measurement. This creates a base estimate that is added to labor, equipment, and overhead to arrive at a total cost estimate. The take-off also includes the prefabricated materials required for the project.

The main challenges of surveyors are creating a 2D plan, converting it into a 3D image and calculating quantities. Below are some of the values ​​included in the sample value calculation.

1. Unit count: This is one of the easiest take-off tasks. Cost estimation calculates the cost of a single unit when planning a project. Calculate the unit price and multiply by the unit price to get the total price.
2. Linear length: The length is specific to materials such as piping, steel and wood. Since it is almost impossible to calculate the unit size of such materials, the values ​​are calculated in terms of unit length. The cost estimator then calculates the length of the combined units and calculates the total weight for the total cost.
3. Surface area: Similar to the stone example calculated above, calculating the area of ​​a work is essentially two-dimensional. The cost estimate measures the length and width values ​​and uses them to calculate the surface area.
4. Weight: Weight is important when calculating shipping costs. When quantifying take-off, we often hear about steel tonnage and backfill weight.
5. Cubic volume: This is where the three-dimensional aspect of quantity calculation comes into play. Examples of quantities that require quantitative calculations include earthworks and concreting.

What Isn’t Included In A Quantity Takeoff?

To avoid errors in quantity calculations, estimators should be aware of some materials that do not need to be included in the figures. Some values ​​will be processed later during the overall cost estimation process. The data that are not included in the quantity calculations are:

• Transportation costs
• Loading and unloading costs
• Scaffolding
• Lapping and waste materials
• Stripping formwork