The slowest zone is not evil, and the slowest trade is not bad. They may have more work to do, the work may be overly complex, or they may not have what they need. When a crew leader leans in with a sense of helpfulness and teaming, the whole train speeds up.
This is Part 24 of my walk-through of my book Elevating Construction Foremen. If you are just joining, start with Part 1. This part is about managing production: optimizing bottlenecks, cycle times, and zones, increasing labor productivity, and reducing variation.
Short answer: Production can be lost quickly if we are not focused on the right system components. Crew leaders manage production by helping the hardest zone and the slowest trade, driving cycle times under the takt time with room for a buffer, speaking up for the right zone size, training their people to full productivity, and reducing the variation they can prevent.
How Do Crew Leaders Optimize Bottlenecks?
A bottleneck is the limiting factor, a constraint, that stands in the way of achieving a goal. The focus is to systematically improve it until it is no longer the limiting factor. Bottlenecks can show up anywhere in the production system design, but they most often show up in zones and trade processes. Usually a zone is too complex or has too much work, or a trade process, work package, or takt wagon is going too slow, is constrained by some limiting factor, or is not ideally organized.
To simplify it, a crew leader can keep an eye on the hardest zone and the slowest trade. Once we notice those, we lean in and help. The key is to optimize, to make the best or most effective use of that trade process or zone, and organize it so it is no longer the slowest or most difficult. Approached with helpfulness and teaming, that improves the speed of the entire train and the pace of the whole site. More in How to Help your Bottlenecks.
How Do You Optimize Cycle Times?
Cycle time is the amount of time a team spends working on an item, task, or process until it is complete, including the wait stages between active work. I use it to describe the time it takes to cycle one trade process in a work package or takt wagon. Take hanging drywall in one zone. Kingman’s formula, loosely translated to construction, says the cycle time will be the projected duration from quantities and production rates, plus time spent on variation, plus time spent on low productivity. See How do you Apply Kingman’s Formula?.
Optimizing cycle times means the crew is learning and improving from zone to zone to reduce variation, increase productivity, and get the cycle time to its lowest possible duration without sacrificing quality. The crew leader does this by intentionally reducing variation and training the crew to increase their capability and capacity at full production. Use your builder mind. I hope all cycle times can be reduced to under the takt time, and further still, to leave a buffer at the end for continuous improvement and rest.
How Does Zone Size Change the Duration of a Phase?
Optimizing zones here means deciding how many zones we have. Little’s Law says the smaller the batch areas, the faster your phase will go. On a 40,000-square-foot floor of interiors, you will go faster with four zones than with two. The formula is takt wagons plus takt zones minus one, multiplied by the takt time, equals the duration. Here is the example from the book’s graphic, with a train of 10 takt wagons:
| Zones | Takt time | Duration |
|---|---|---|
| 2 zones | 4 days per zone | (10 + 2 − 1) × 4 = 44 days |
| 4 zones | 2 days per zone | (10 + 4 − 1) × 2 = 26 days |
Same work, same people, same crew sizes, and the same overall duration per trade. The difference is that smaller zones let successor processes, work packages, and takt wagons start earlier. A great project team analyzes this together and decides the right zone size and number. You may want to default to asking for large zones, but math, science, and reality prove it will take you longer. Speak up and help find the balance between enough room for tools, materials, and work and a zone that lets the train flow smoothly.
How Do You Increase Labor Productivity?
I define labor productivity as the productivity levels of the labor force. The focus is to increase their capability through training, equipping them properly, providing the right environment to work in, and giving them enough time to do the work properly in the right time blocks. A great crew leader keeps an eye on these productivity levels and trains to the desired level. That training is yours to provide for your workers.
Why Is Variation So Costly?
Variation is a nasty thing, and it always leads to waste. It involves alteration, addition, omission, and substitution in the quality, quantity, and schedule of work. Its sources include the performance of construction parties, resource availability, environmental conditions, the involvement of other parties, and contractual relations. Some variation is inevitable and some is not. The key is to prevent what we can and react to what we cannot predict or prevent.
The Law of the Effect of Variation says that as variation increases, it extends the duration of your project or phase. As a crew leader, you can hold the opinion that sometimes things must change, and sometimes things should stay predictable. Work with the project team to tell the difference, hold to the stability you can, and change only what you must. More in Controlling Variation.
Each of these five sets a ceiling on your crew:
| Managing production | You could be the best in your field and still not go faster than… |
|---|---|
| Bottlenecks | Your slowest trade process or zone. |
| Cycle times | A cycle time with variation and low productivity will let you. |
| Zones | Your zone sizes will let you, per Little’s Law. |
| Labor productivity | Your people are trained to go. |
| Variation | The variation in the work will allow you to. |
So here is the challenge. Name the hardest zone and the slowest trade on your project this week. Then go ask that crew leader what they need, and offer one thing your crew can do to help.
Bottom line: Find the limit, help the bottleneck, train your people, and protect the stability you can.
If your project needs superintendent coaching, project support, or leadership development, Elevate Construction can help your field teams stabilize, schedule, and flow.
On we go.
Elevating Construction Foremen series:
Previous: Part 23: Leveling Work: Production Rates, Zones, Work Packages, Labor, Materials, and Buffers
Next: Part 25: Crew Leader and Superintendent Communication: Pre-Staging, Handoffs, Layout, Training, and Logistics
FAQ
What is a bottleneck in construction production?
A bottleneck is the limiting factor that stands in the way of achieving a goal. It most often shows up as the hardest zone or the slowest trade, and the focus is to improve it until it is no longer the limit.
What is cycle time?
Cycle time is the time it takes to complete one task or process, including the wait stages between active work. Kingman’s formula, loosely translated to construction, adds time spent on variation and low productivity to the projected duration.
Do smaller zones really make a phase go faster?
Yes. Little’s Law says the smaller the batch areas, the faster the phase. Ten takt wagons through two zones at a four-day takt time take 44 days; through four zones at a two-day takt time, 26 days.
People Also Read:
Lean Onboarding Series – Bottlenecks
Takt Time vs. Cycle Time: The Crucial Differences for Builders
Lean Onboarding Series – Variation
Theory of Constraints Explained
If you want to learn more we have:
-Takt Virtual Training: (Takt Virtual Training)
-Check out our YouTube channel for more info: (Elevate Construction on YouTube)
-Listen to the Elevate Construction podcast: (Elevate Construction Podcast)
-Check out our training programs and certifications: (Training Programs and Certifications)
-The Takt Book: (The Takt Book on Amazon)
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