Quantity take-off

What is a Quantity Takeoff?

Quantity take-offs are a detailed measurement of materials and labor needed to complete a construction project. They are developed by an estimator during the pre-construction phase. This process includes breaking the project down into smaller and more manageable units that are easier to measure or estimate. The level of detail required for measurement may vary. These measurements are used to format a bid on the scope of construction. Estimators review drawings, specifications and models to find these quantities. Experienced estimators have developed procedures to help them quantify their work. Many programs have been developed to aid in the efficiency of these processes. With BIM quantity take-off can be conducted almost automatically given that the type of materials, their quantity and price is included in the model. It is known that construction projects often run overtime and over budget and one of the reasons is lack of accuracy in quantity takeoff and estimates.

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Conducting a Quantity Takeoff

Doing a quantity takeoff is a specialized skill that requires time and resources. While you can perform it manually, doing it digitally enhances the accuracy of the process. This is because it reduces the scope for human error.

Any wrong calculations done during this phase can snowball into significant, costly mistakes so you want to make sure that your takeoffs are as accurate as possible.

Whether you choose to do it digitally or manually, the formula involves the same two parts:


1. Input

To achieve an accurate quantity takeoff, you need to input the correct data needs into the models. Whether you are working with a hand-drawn sketch or a detailed 3D building model, it’s crucial to manage the data correctly.

You need to use precise information here. This is where tools like RealEstimateService’s quality checks can come in handy. It will help you to ensure accurate quantity takeoffs due to high-quality planning.

The estimator is not usually in charge of preparing the concepts or designs so they need to be able to trust the data they are given. So, you want the planner to deliver high-quality data and, to achieve this, it’s best to use quantity takeoff software.

This process can further be enhanced through features like model checks. With RealEstimateService, you can achieve this through clash detection and model checks that use default or custom rule sets.


2. Output

The output stage is about taking the concepts from planning and converting them into the physical requirements for the project.

Basically, you take the building idea and estimate the exact material quantities required for the project to take shape. Having accurate material estimates is essential here. This is the part of the process where you can create actual figures and realistic estimates to give life to the project. With this data, you create your bids. The more accurate this process, the more successful your bids will be.

The output process is also often an input into a different tool. For example, you can input the data into estimation software to create a costing. Using software like RealEstimateService allows you to do this as seamlessly as possible through its open API.

Key areas of focus during this process include identifying the materials, quantifying this data, and aligning this data to a pricing system. This will help you to achieve a realistic project proposal.

Aside from volume of materials, is there anything else to include?

When assigning a price during the construction takeoff process, it is important to incorporate any expected changes to material prices that may impact the total material costs.

For example, suppose the market is experiencing higher-than-normal prices for steel. In that case, the estimator may take this into account and increase the total cost for the steel in the project to account for any increases.

Anticipating future cost increases for raw materials is one of the more challenging parts of the construction takeoff process. This is because it requires a high degree of skill and judgment to do correctly.

The estimator must have extensive knowledge of current material prices and an understanding of any market forces that may exist that could cause those material prices to fluctuate.

Difference between a takeoff and an estimate

The difference between a takeoff and an estimate is something else that can be confusing to those new to the construction industry.  The concept is pretty simple once you know it but it can still trip some people up.  A takeoff is simply determining the amount of all the materials needed for a job.  That’s it!  Takeoffs don’t have any material costs associated with them and don’t include extra costs that an estimate does.

In contrast, an estimate takes the takeoff a few steps further.  Estimates apply costs to all the materials determined by the takeoff and adds in other costs the contractor will face.  These extra costs include things like travel costs, tax, applying a waste factor, labor costs, and any other extra costs you’ll face.