The Bridge

One of my earliest and most humbling experiences as an estimator is the topic of our discussion this month: the use of schematics for referencing purposes.

My higher education was in architecture. Looking back on it, I can honestly say that my real education began when I graduated and entered the fast-paced world of the New York City construction industry. A professor I admired told me that to be a better architect, I should spend some time in the construction industry.

I took his advice, and upon graduation I was hired as a junior estimator by a prestigious NYC subcontractor, Circle Industries. It was good advice except for the fact that it quickly revealed two things to me: the shortcomings of my education in architecture, and the fact that architects are mere mortals—just like the rest of us. I liked estimating and discovered I had a talent for it, so I stuck with it. Besides, I was a terrible draftsman, and in the mid-'80s, good drafting skills were still required for apprentice architects.

For my first solo assignment as a junior estimator, I was given a high-rise apartment building on the Upper West Side of Manhattan. It was a large and important project and I knew I was being thrown into the water to see if I could swim. Liking a challenge, I earnestly proceeded to produce a comprehensive quantity survey and cost analysis. Confident in my ability, I rolled up the drawings and presented the folder to the chief estimator for his review. When I came back from lunch that afternoon, the drawings and folder were on my table with a note on it from my boss that said, “Check it again—there’s a problem.”

Manhattan Mystery

How could it be? I had been so thorough and meticulous bringing to bear all I had learned from the seasoned pros around me. I checked and re-checked but could find only one or two minor oversights. I approached the chief estimator (who was always patient) and pleaded my case that although I had reviewed the entire estimate carefully, I could not find an error of any consequence.

When we reviewed the drawings, he turned to the building elevation drawing and said, “You’ll find the error here.”

I had reviewed this drawing in a precursory way, mainly to verify the lower floor heights; I had not used it to determine all the floor-to-floor heights as I should have. I had used various wall sections and details to do that since I could determine all slab thickness from the 3/4-inch scale wall sections and the floor-to-floor heights were typically given in the same section for most of the floors. He watched as I reviewed the elevation carefully.

The wall section I had determined several floor heights from said, for example: “Floors 10 to 15” and gave a floor-to-floor height of 8 feet, 8 inches. This meant that all these floors were the same height with a floor-to-deck height of 8 feet (floor-to-floor less the slab thickness of 8 inches). If the heights were right, what could be the problem? “OK,” I said, “I give up.” He said, “Count the floors from 10 through 15 on the elevation.” I began counting, “10, 11, 12, 14, 15 … wait a minute, what happened to the 13th floor?”

My error was one of oversight. There was a constructed 13th floor, but it was the numbered floor 14 on the plans. Floors 10 through 16 had a common floor plan with floors 10 to 15 at 8 feet, 8 inches and floor 16 at 10 feet, 8 inches—16 being the offset or transition floor—but I had accounted for this. The error occurred in my determination of the multiplier for floors 10 through 15 on the elevation. I had applied the standard formula for determining the number of floors that is {(FLOORhigh - FLOORlow) + 1}. In this case, I had determined the multiplier to be six {(15 - 10) + 1}. This formula works only when the floors are in a consecutive numbered sequence that is not the case when a floor is missing from the numbered sequence.

Superstitious results

The result was I had one too many floors in my estimate (about $150,000 extra). In the intervening years, I have run into this situation rarely but on occasion—mostly it occurs in high-rise hotels where guests may be reluctant to stay on the 13th floor. When it occurs in apartment and/or office buildings, which is less frequent, the architect will usually sequence the floors 11, 12, 12A, 14, substituting

an abbreviated number for the 13th floor rather than skipping it completely, as was the case here.

I could not blame the architect for my error: The information for determining the lack of a 13th floor was provided on the drawings—even though it was inconspicuous. It would have helped had there been a prominent note on the floor plan and/or the wall sections that stated, “Beware, there is no sequentially numbered 13th floor,” but it was not required nor is it normally given (though I have seen such notes on other plans).

Human superstitions are not part of the curriculum at any school of architecture so I had no prior knowledge of this sort of situation. I learned the value of a proper schematic height diagram from this experience and now I check the entire floor numbering sequence of every building I work on—not just the presence or lack of a 13th floor—and I always refer to the overall building elevations and sections.

This “war story” about the importance of schematics provides the foundation for next month’s article. We will use an actual schematic height diagram from a building I recently worked on and provide a detailed explanation and description of it. To some trades—flooring, for example—the determinable heights of a building are inconsequential but to most of the trades it matters a great deal. Of all the types of schematics used for reference purposes, I believe the height diagram is most important. From it, the criteria for establishing much of what comes later in an estimate is made.

The moral of the preceding story is to learn from your mistakes and make every effort not to repeat them; that is the greater sin than the mistake itself. People will always make mistakes—that’s why pencils have erasers.