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    On the Job

    ‘Human calculator’ does the construction in his head

    John Chereski (right) worked with Leland Alexander to estimate costs for a synagogue renovation.
    Josh Reynolds for The Boston Globe
    John Chereski (right) worked with Leland Alexander to estimate costs for a synagogue renovation.

    It’s more than blueprints and math for construction estimator John Chereski, also known as the “human calculator” at his firm, Kaplan Construction of Boston. Whether it’s a commercial building, home remodeling, health care facility, or multifamily unit, Chereski creates a budget and thinks through all the expenses to determine a project’s feasibility.

    What’s the process you go through for estimating a job?

    I construct the building on paper and in my head; it’s the most thorough way of making sure that every detail is covered. This includes plugging in costs for every item.

    How much variance are you allowed?

    I’m not allowed any. The owner doesn’t want to want to hear, “Oops, it’s $100,000 more than I told you.” A good conceptual estimate is 3 to 4 percent, plus or minus, of what I figured. Of course, if it’s less, they love it; if it’s more, it’s not good.

    How much easier does software make your job?


    I couldn’t live without Excel. I may also use BIM, or Building Information Modeling, a 3-D imaging program that can layout the physical construction of a facility, such as where ductwork and pipes might run above a ceiling. But nothing is better than actually going to the site and sticking your head above a ceiling.

    How do regulatory requirements and other conditions play into an estimate?

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    Most towns have a general building code, but there may be a lot of other little [nuances] to consider. For example, a fire alarm system can be different from city to city. Each of these has different costs.

    What’s your thinking when it comes to soliciting bids?

    An entire project might have a couple hundred bids, but I try to only solicit three or four bids per trade. A lot of people think the more bids the better, but if you solicit too many bids, subcontractors get discouraged, so they either don’t bid or give a high estimate. I like to get three bids.

    How did you get into this line of work?

    My parents did renovation work on their Colonial home in Western Massachusetts. I was the one who had to rip apart the walls and bring the debris to the dumpster. I went to school for construction management and worked in the field, then fell into the groove of estimating.

    One risk factor for cost is extreme weather. Has the recent extreme weather thrown a kink into budgets?

    It’s a risk you can’t control, but I look at past jobs and see what weather cost at that time and try to extrapolate.

    Has your ability to estimate helped you in your personal endeavors?


    I’m really good at buying a car since I know how to deal with people and negotiate. It was just like working with all the subcontractors that I need to deal with on the job.

    Cindy Atoji Keene can be reached at