Math has never been my strong point. In my work, I rarely have problems that can’t be solved with the help of a construction calculator, or a phone call to a more mathematically fluent friend. Fortunately, most of the time I’m calculating simple linear or square footage.
A few years ago, I went to estimate a whole house paint job. To do this, I need to know the square footage total of all surfaces to be covered. I charge a price per foot, and also use the total square feet to estimate the number of gallons of paint needed. My way is to measure the area of the floor of each room. From this measurement, I can then find the sum of the square footage of the walls:
If the footprint of a room is 10′ x 10′ and the walls are 8′ high, each wall will be 80 square feet. If I multiply that by 4, I have 320 square feet of wall space to be painted. If the ceiling is included, I will add 100 (because if the floor is 10′ x 10′ the ceiling is 100 square feet). I now have 420 square feet of wall and ceiling to be painted. Of course it’s not quite that simple because I have to allow for doors, windows and whatever else is subtracted from coverage. I will go room by room taking measurements.
Are your eyes glazing over yet? Me too – it’s a tiresome process. Here’s where it gets better…
I went through my calculations as quickly as I dared, not wanting to stay any longer than absolutely necessary. I don’t charge for estimates, and I don’t like loitering in potential customers homes scratching my head at numbers. I don’t use estimating programs/apps, and I don’t necessarily trust myself with calculators. I know it’s old school – but I trust a ruler, pencil, paper and previous experience. I announced my number and left.
A couple days later I got an email from the homeowner. It stated that my estimate was for twice the square footage of the actual house: “…Can we assume that your square footage estimate was off by half so can we maybe negotiate your price based on that?”
My first reaction was that I had made an colossal mistake in my arithmetic. I did that a lot in school. But when I gave my estimate at the house, my number “felt” right. I had done jobs of this size before. Looking over my numbers again and again, I came to understand that the homeowner was going by the square footage of the footprint of the house.
I emailed back and showed step by step how I arrived at my estimate, but I did not hear back. I imagine they were pretty embarrassed at trying to call me out on such an huge error.
I try to encourage homeowners to get more than one estimate. Most (if not all) contractors do this for free. And these days, I always ask if they have some idea of what the job is supposed to cost. Google is your friend.