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Building Science

The Lost Art of Quality Control

A quality control failure led to a strange border at Bill Spohn's home [Photo courtesy of Bill Spohn]

I’m sure you’ve heard the saying “Measure twice, cut once.” It’s easy to take it too literally and think it applies only to things you cut. In reality, it is the maxim of quality control. It means, “Think, check, and double check. And then sometimes you need to get someone else to check you too.”

The following video covers this important topic:

A look in the mirror

Here’s an example. Years ago, someone I knew was having a house built. They had gotten plans for a house that fit perfectly on their lot. Then they broke ground and the contractor poured the concrete foundation walls for the basement.

When the excited homeowner went to check it out after the pour, he made a sickening discovery. The house was supposed to be mirrored from the plans when built. The contractor didn’t do that. Oops! Someone missed that important detail and lost a lot of money when they had to rip it out and do it over.

A strange border

Here’s another one. Last year I did a book tour and visited Bill Spohn at his new home in Pittsburgh. It’s an absolutely gorgeous home that also happens to be a high-performance home with great indoor air quality, solar electricity, and more. I really loved the way the house melds seamlessly between indoors and outdoors.

The sidewalk mistake resulted in extra cost for trenching and putting in the curb to keep the soil from being too high on the foundation. [Photo courtesy of Bill Spohn]
The sidewalk mistake resulted in extra costs for trenching and putting in the curb to keep the soil from being too high on the foundation. Photo courtesy of Bill Spohn.
Or almost seamlessly, I should say. The lead photo and the one just above show the evidence of a quality control failure. That little border a couple of feet out from the foundation wasn’t supposed to be there. The need for it arose when a contractor built the sidewalk on top of the dirt instead of excavating as he was supposed to. Unlike the homeowner I mentioned above, Spohn didn’t make the contractor redo it.

A few failures in my basement remodel

I’ve been working on a basement renovation. You can read a lot about it here in this blog and watch related videos on our YouTube channel. I’m not acting as the general contractor because it’s a big project, and I’ve got other things going on.

Here are a few of the problems that have cropped up.

Bathtub out of level. Recently I was trying to install the surround kit for the bathtub in our guest suite. There was a gap at the bottom of the side panels that grew from the back side to the front.

Bathtub out of level by 3/4 of an inch
Bathtub is out of level by 3/4 in.

Turns out the bathtub hadn’t been set properly. It was 3/4 in. out of level—along the short side. Why?

Bathtub shims beneath foam
Bathtub shims beneath foam

The answer is in the photo above. Rather than setting the tub in concrete or mortar, they used wood shims under the foam.  It may have been level when they first installed it. The first time anyone put weight on the tub, however, the foam compressed, and the shims weren’t doing anything.

Window supports. A quality control failure that happened a few months ago was the result of a contractor not doing what we told him to do. They were installing angle iron above two window openings, and my GC told them not to remove the concrete blocks above the window.

Broken concrete block above basement window
Broken concrete block above basement window

Well, you can see above what they did. It turned out OK in the end, but my GC and I had told the contractor three or four times not to do it that way.

Advice for better results

I wrote about my basement frustrations in a LinkedIn post recently and have gotten 130 comments so far. There was a lot of commiseration from commenters sharing similar experiences. And I’m not just talking about homeowners. Many of these were home builders, engineers, architects, and trade contractors.

Several commenters echoed this comment from Joshua Graves: “This is why I prefer to do as much as I can myself.” I told them I agreed generally but that this was too big a project for me to do alone. Here I am nine months in with a general contractor running things, and I’m still not done.

And then there was some really good advice. Todd Usher, a home builder in Greenville, S.C., said it best:

Boy don’t I know this challenge!  The only way we have been able to overcome this is with a Quality System—no matter how small the job.

1) Start with a thorough scope of work that includes more visuals than words to read. “Visual Scopes” are effective. It’s amazing how many trades don’t even follow the manufacturer’s instructions!

2) Hold “day 1” meetings with each trade to review the scope for the work they are about to start.

3) Quality Inspection of the work to the scope. No payment until quality inspection is passed.

Don’t forget the critical link

You can have the best plans in the world. Every detail can be specified completely. And you still can have failures that drive you nuts. Why? Because you have to have a way of communicating those details to the people doing the work.

Case in point: Yesterday the drywall finishers showed up to put the first coat of mud on my new drywall. The contractor came over twice to go over the project, and we discussed the drywall returns we wanted at the windows. On the sides and top of all four windows, we specified bullnose corner beads. The contractor discussed the details with the workers before they began yesterday morning.

How could you prevent this detail from going wrong?
How could you have prevented this detail from going wrong?

What do you see above? They got the bullnose on the top but not the sides.

The problem here was that the contractor doesn’t have a system to communicate these details effectively. Yeah, he went over it with them on the phone, and we see how well that worked. What they needed was to have those places marked so the workers wouldn’t have to remember what they were told at the beginning of the day. It would be right there in front of them when they got to it.

This would fall under Usher’s “visual scopes.” They shouldn’t have to rely on memory. The more complex the job, the less reliable memory is. The workers need visual cues, especially for anything out of the ordinary.

What quality control failures have you experienced? How did you fix them? How would you prevent them? Let me know in the comments below.


Allison A. Bailes III, PhD is a speaker, writer, building science consultant, and the founder of Energy Vanguard in Decatur, Ga. He has a doctorate in physics and is the author of a bestselling book on building science. He also writes the Energy Vanguard Blog. For more updates, you can follow Allison on LinkedIn and subscribe to Energy Vanguard’s weekly newsletter and YouTube channel.

5 Comments

  1. paulmagnuscalabro | | #1

    GREAT article, Allison. I can't wait to read the comments here; I hope they're lengthy.

    On the rare occasions when I have the money to bring in someone to do the work on my house (rather than me doing it), I've found that I pretty much need to be there 50% or more of the time. It doesn't matter how clear the objective is, so many questions come up where the solution I want is not the answer that would have been the tradesperson's first choice. I think a big part of this is that if you're a sub being brought in for one piece of a bigger puzzle, there's so much context you just won't be privy to, no matter how well-intentioned.
    I love the idea of "visual scopes," and it's something I see very often from high-end GCs but I've never had a name for it.

    1. GBA Editor
      Allison A. Bailes III, PhD | | #4

      Glad I could pass that along, Paul. Todd Usher gets the credit for it; he's the first person I heard it from anyway.

  2. dustin_7022224 | | #2

    Building a new home, had the exterior painted this fall. One of the things I did was to put a few brush strokes of paint in any place that was not obvious about what color it was supposed to be, ie pieces of trim, transitions, etc. As Alison wrote, it makes it obvious when they get there as to what you want.

    1. GBA Editor
      Allison A. Bailes III, PhD | | #3

      Excellent! It seems obvious after you know about it, but it's so rarely done.

  3. Teokele | | #5

    During my recent kitchen renovation, a simple cabinet installation turned chaotic when doors arrived completely misaligned. Turns out the installers just eyeballed it instead of measuring.

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