Here’s the deal. In Lean construction, we have been decoding concepts from Japanese car manufacturing, and from manufacturing in general. Now we are finding out how those concepts tie into the greater concept of how you actually build construction projects, and I am really excited about it. The three Ms are Muda, Mura, and Muri, and they allow us to analyze the system.
Short answer: The three Ms are Muda (waste), Mura (unevenness), and Muri (overburden). On a field walk, look at the crews for all three: waste like overproduction, excess inventory, and double handling; unevenness like unleveled zones, unleveled crews, and bottlenecks; and overburden like too much overtime, too many work areas, and not enough people for the task.
Looking at the Train
Whenever I see the train of trades moving through a project, through zones, I am always analyzing it. The things that adjust the speed of the train are called constraints. The things out ahead of the train are mostly roadblocks. If it is a mountain or a water feature, that is a constraint as well. But once you have built the train tracks, built the path around the constraints, anything on the tracks that could be in your way is a roadblock.
We have to get into the mindset of visualizing construction as this train going along the tracks through the zones. When I analyze it, and specifically when I look at the crews, I am always looking for waste, unevenness, and overburden. Muda is waste. Mura is unevenness. Muri is overburden. I love the little check card for this, and I wish everybody had one so they could look at it in the field.
What Is Muda (Waste)?
Let’s start with the common one. When we overproduce something, we then have excess inventory. Overproducing could be doing too much work in an area, or working too fast, or installing drywall in the building before the exterior is buttoned up so that it is going to get damaged. We have overproduced, and now we have an excess inventory of uninstalled or installed work.
The problem with excess inventory is that it can get damaged, or if it is not installed, it has to get moved. John Kauffman told me about a study that he did, or saw being done, on one of his projects where a bunk of plywood had to be moved nine times before it was actually installed.
From there, the waste chain continues.
- Damage, trade damage, and movement produce defects.
- The movement results in transportation, which is a waste because it costs money and time, and in motion, which is a waste because it injures or wears out our workers’ bodies.
- Fixing those defects, plus the transportation and motion, is overprocessing, doing more work than would have been needed.
- All of that results in waiting, and waiting means we are underutilizing talent, because all of the waste happened in the first place when we did not use the wisdom of the team.
Those are the eight wastes: defects, overproduction, waiting, unused talent, transportation, inventory, motion, and overprocessing. Everybody knows them. I have them on my card. If we got used to looking at them the way Paul Akers describes, we would be able to see what bugs us and then take incremental steps to fix what bugs us.
What Is Mura (Unevenness)?
When you are on your field walk, I am asking you to look for unevenness in the work. Niklas Modig describes three main causes of productivity loss, or a lack of flow, in This Is Lean, the book he wrote with Pär Åhlström. One is variation. Another is too much work in the queue per Little’s Law, meaning too many flow units in process, which means we are batching. The third is stops and restarts. A roadblock causes a stop and a restart, which interrupts our flow.
Here are the places I look for unevenness.
- Delayed work, meaning work is not done out ahead or we do not have the right tools or materials.
- Production loss, when the team is tired, fatigued, or slowed down, or something in the team dynamic is costing production.
- Unleveled zones, where there is more work in one zone than another as you go from zone to zone.
- Unleveled crews, where a crew in the train of trades is either understaffed or has too much work to do.
- Too much variation.
- Bottlenecks, which can come from a trade process or from a zone. The work itself can be a bottleneck in a certain part of the sequence, or a zone can simply be really, really difficult.
All of these things cause unevenness, and I want you to be looking out for them.
What Is Muri (Overburden)?
Overburden is what happens when workers are being pushed beyond their capacity. You will see that they are tired, fatigued, annoyed, and angry. I will remind all of us that portable toilet conditions, graffiti, and trashy jobsites come from workers who are angry, and that usually comes because they are overburdened. If you see graffiti or nasty bathrooms, either the jobsite has not made it clear that it is unacceptable, or the workers are trying to tell you something.
When we have to catch up somewhere, sometime, we never, ever, ever, ever push workers to go fast. We want to create flow so they can naturally flow, which means we fix things on the jobsite to increase capacity. Here is when you have overburden.
- Workers are working too much overtime.
- Workers have too many areas to work in. Not only does that overburden them, the waste of switching from area to area, or having too many areas to supervise, adds additional hours.
- There is too much context switching from working in too many areas.
- There is too much zone work density, meaning too much work in the zones for the time given.
- There are not enough people for the task.
- Working conditions cause fatigue, such as overly cold or overly hot conditions.
- People are working beyond their training. We never do that, but if it is happening on your jobsite, it will overburden people.
- There is a lack of needed resources, because people have to scramble, go on treasure hunts, and spend most of their time just getting what they need.
- The work is too complex.
- There is a lack of breaks or a lack of buffers in the work.
Memorize All Three
We are not just looking for the waste. Our construction industry has not even gotten to the point where we have memorized the waste. I have, but we need to get to the point where we have memorized waste, unevenness, and overburden.
Waste happens when we are doing things we should not do. Unevenness happens when the work that we should be doing does not flow. Overburden happens when the work that needs to happen and flow is beyond our current capacity.
I have cards for this. If you want to reference them, or want me to send them to you, let me know.
For more on creating flow without push, see Flowing Together on a Takt Time & Pull.
So here is the challenge. On your next field walk, look at the crews and ask whether any of the three Ms are affecting your people. Waste, unevenness, and overburden.
Bottom line: We never push workers to go fast. Fix the jobsite so they can flow.
If your project needs superintendent coaching, project support, or leadership development, Elevate Construction can help your field teams stabilize, schedule, and flow.
Want your team trained on this? See our Last Planner® System and Takt training.
On we go.
FAQ
What are the three Ms?
Muda is waste, Mura is unevenness, and Muri is overburden. They let you analyze the system, and I look for all three whenever I watch the train of trades moving through the zones.
What is the difference between a constraint and a roadblock?
Constraints adjust the speed of the train, like a mountain or a water feature. Once you have built the tracks around the constraints, anything on the tracks that could be in the way is a roadblock.
What are the three causes of lost flow according to Niklas Modig?
Variation, too much work in the queue per Little’s Law, which means too many flow units in process and batching, and stops and restarts.
What can graffiti and nasty bathrooms tell you?
Either the jobsite has not made it clear that those behaviors are unacceptable, or the workers are trying to tell you something, often because they are overburdened and angry.
People Also Read:
Lean Onboarding Series – Waste, Unevenness, & Overburden
8 Types of Waste in Lean Construction
Monthly Field Walks
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