Mastering Take-Offs for Estimating Construction Projects
Before an estimator can bid for or start a project, they need to know the types and quantities of different materials they will need to complete it. This ensures a proper estimation of the costs and requirements for the materials and will also give an indication of the labor costs involved in the installment or construction of said materials.
How to Create the Most Accurate Material Takeoff
This process is known as takeoff — or material takeoff (MTO) — and is an essential part of the estimating process. For a small one-off job, an experienced builder should be able to estimate the materials required in his or her head. A more thorough process is necessary for major construction projects, however. It is important to approach the task in a methodical manner in order to achieve the most accurate approximation possible. As well as providing a precise estimate for yourself and your client, this will also help the job run smoother on the ground by ensuring that your workers or contractors have everything they need.
It is worth noting that, while a thorough takeoff will improve your estimate, there will be other factors to take into account. These include your office overhead costs, shifts in market prices for materials, and various other expenses.
What to count
Essentially, the takeoff should quantify all the materials needed to complete the building, structure or project. This does not include assets such as tools and equipment, which are also required to do the job but should include all the physical materials that go into the project. This could be raw materials such as concrete, timber or sand, as well as prefabricated materials; bricks, lengths of electrical cable, plumbing pipes, and light fixtures.
In addition to counting the materials, the MTO should also specify the type of material required. This could be the grade of steel or the type of electrical cable, for example.
Different contractors might have a diverse range of requirements when it comes to compiling their takeoff. A roofing specialist will use different materials than a concrete contractor, for example, but the principles of takeoff are broadly the same.
There are four key types of measurement required for the takeoff in most construction projects.
The estimator will need to count the numbers required for specific individual items. These could be anything from the number of light fixtures required for a given building to the number of studs necessary to finish the project.
Some items, such as cables and pipes, are measured primarily by length. You will also need to know other dimensions, such as diameter, but this information will be included with the type of material required. You might need to allow for extra amounts for elements such as drops for switches, receptacles, and panels when measuring electrical cable.
Some materials will require a measurement of the surface area. This could include elements such as flooring, cladding, or an estimate of the amount of paint needed for a given structure.
Measurements of volume may be needed for some materials, such as the amount of asphalt used per yard or the concrete required to lay a foundation.
There are two main types of takeoffs
- Manual takeoffs
Many construction design professionals still use traditional paper blueprints and plans, and it’s possible to conduct an accurate takeoff from these materials.
However, it is crucial that the estimator be able to accurately read blueprints and plans for the type of work being quantified (general building plans, electrical and plumbing schematics, etc.). As well as diagrammatic representations of the dimensions of the project, these will contain various symbols and notes that may indicate the types of materials required.
Working from these plans, you can use colored pens, pencils, or markers to distinguish the different items and types of material specified. As paper blueprints can be expensive and time-consuming to produce, many estimators are adopting new technology to perform their estimates. If you’re still using paper, you might be expected to use a clear plastic overlay rather than marking the blueprint directly.
You can then transfer the quantities and materials to spreadsheets or use various preprinted forms and worksheets that can help you to work out the exact material costs for each component.
- Digital takeoffs
While it’s possible that manual takeoffs can be used to produce an accurate estimate, they can be complex and laborious. They can also throw up errors if you get a measurement, count, or calculation wrong.
Many companies are increasingly producing digital blueprints. There is also a range of takeoff software available that can be used to streamline and partially automate the takeoff process. The specifications of these software packages may vary, but all basically allow you to analyze blueprints and enter the quantities and measurements required in a digital format. Some systems are integrated into a bidding or quotation program, allowing you to combine the two processes.
Breaking down the process
The exact details can vary depending on a number of factors, including your specialization as an MEP estimator, the types of drawing used, any software you are using, and the type and scale of the job. The drawings and specifications will be slightly different, but the general techniques are the same.
Here we break down the basic manual takeoff process for the electrical components of a project.
- Counting the symbols
Counting symbols will allow you to identify the number of components required to complete the job. The blueprints and drawings you are working from will use standardized symbols to represent different elements such as fixtures, switches, and convenience receptacles. You will need to familiarize yourself with these symbols and what components they denote. Other, non-standard components may be identified by a key included on or with the drawings.
Count each component type individually. Some people manually do this using a handheld tally counter that you click to add each unit. This can help ensure accuracy but can get tedious. You should also mark each symbol with a colored pen or pencil to signify that it has been counted and to avoid counting it again. As you complete the count for each component on each page, enter the quantities on a working scope sheet. After you have worked your way through every page of the blueprint, add the totals for each different component.
- Measuring the circuits
You will also need to measure the circuits shown in the drawings. First, check the scale used for each page that you measure. You will often find the scale dimensions listed in the title block of the drawing, but be aware that the scale can vary on different pages — check carefully for scales listed on each page.
It is also worth noting that if you are not working from original blueprints, they might have been copied at a reduced size. Confirm the scale is accurate (there may be a 1 inch or 1 cm scale marker) or contact the architects/designers if you have any doubts.
There are a number of tools you can utilize to take measurements from drawings. These include an architectural ruler, scaled measuring tapes, and mechanical and electronic measuring wheels. Rules and measuring tapes are fine for quick measurements in small dimensions, but a measuring wheel is both convenient and accurate.
You can now measure the branch circuit for each component in the drawing — remember to allow for and add in the drops at each switch. Some electronic scale wheel devices allow you to press a key to add a set distance for drops. This is fine if all the drops are standardized, but you will have to reset the constant each time if they are of different sizes.
There may be different circuits (two-, three- or four-wire) marked on the same drawing. Trace each one with a colored pen or pencil once you have finished measuring, using the same color for the same type of circuit.
- Calculating the takeoff
You can now use your counts and measurements to produce a takeoff figure. Using trade market values (generally building in a small buffer for price fluctuations), you can provide a relatively accurate estimate of the cost of the materials involved. With the right time and motion data required, you can also gauge the scale of the job to project approximate labor and other associated costs.
These tips for understanding how to master the MTO should help you get your project off the ground. An effective estimate is vital when working on a construction project, so follow these guidelines for the most cost-effective solution when approaching your new development.