Lean Construction

May 9, 2023

Many years ago, a younger Lason was slogging through another semester of engineering school, wondering if he was really cut out to be a mechanical engineer, but determined to finish (he had already dropped out once), when through the haze of tedious lectures on shear moment of inertia, arduous proofs of differential equations and mind-numbing exams on the crystalline grain structure of high carbon steel came an intriguing topic: Lean Manufacturing.

According to lore, Taiichi Ohno, an engineer for Toyota, visited the assembly lines of Ford Motor Company in the 1940s or 50s, and then proceeded to develop the Toyota Production System which led to Toyota’s domination of the global automotive industry. The tenants of the Toyota Production System have been termed lean manufacturing, and have been adopted by manufacturing companies around the world.

There are several aspects to lean manufacturing, but they can almost all be boiled down to an unrelenting drive to eliminate waste. According to the principles of lean manufacturing, there are eight different types of waste:

1. Overproduction: Producing more than what is needed or before it is needed, which leads to excess inventory and storage costs.
2. Waiting: Idle time that occurs when workers or machines are waiting for the next task to be completed.
3. Transportation: Unnecessary movement of materials or products, which adds no value and increases the risk of damage or loss.
4. Processing: Performing unnecessary or redundant steps in a process, which wastes time and resources.
5. Motion: Unnecessary movement or motion of people or equipment, which wastes time and energy.
6. Inventory: Excess inventory or materials that are not being used or processed, which ties up capital and increases storage costs.
7. Defects: Products or services that do not meet customer requirements or expectations, which lead to rework, repair, or rejection.
8. Unused talent: Failing to utilize the knowledge, skills, and creativity of workers, which leads to missed opportunities for improvement and innovation.

In the 1990s some construction companies began to take notice of the effectiveness of lean manufacturing and started implementing lean manufacturing principles in construction. Although there are similarities between construction and manufacturing – both involve materials, time, and energy, and culminate in a final product – construction can be much more complex due to the unique nature of every project. Even if the same plan with identical finishes were used, it would still present different challenges depending on the site, weather conditions, and other variables.

Despite this complexity, lean construction still recognizes the same eight types of waste as lean manufacturing. However, the approach to addressing these wastes may differ due to the specific challenges presented in construction. So what are some examples of the 8 types of waste in a construction context, and what are some approaches you can take to reduce waste and become more lean? We’ll go through the 8 types of waste and give some examples of what that might look like in the real world, and then we will discuss 5S and other techniques that you can use to reduce waste in your construction business.

Examples the 8 Types of Waste

1.  Overproduction

Overproduction occurs when too much of something is created, or – perhaps more often in construction – when too much of something is done before it is needed. Overproduction in construction seems to come up often when something is running behind schedule: maybe the painters are behind, but we want to keep things moving forward so we get the other trades in before the painters, which means the painters have to do more work masking (4. Processing, 5. Motion), and get even further behind, making things worse. Another type of overproduction would be when something is scheduled and completed early in the process of a project, but it ends up getting dinged up and damaged over the course of the project and needs to be repaired (7. Defects).

2. Waiting

Waiting is pretty self explanatory, and will come up any time you have trades waiting on other trades. This could be for anything from a few minutes to a few hours. Waiting will also occur if people aren’t equipped with the materials, knowledge or power (8. Unused talent) to perform a task or make a decision and they need to wait on a delivery or on higher ups.

3. Transportation

Transportation waste is any movement of products or materials that are not necessary. This could include moving stuff around in your shop or the job site because it is in the way, or transporting materials to the job site and back because they had flaws or the job was not actually ready for them. Another thing to note is that any time a material or product is moved, whether it’s from one location to another in your shop or on the job site, or between your shop and the job site, there’s a risk that it will be damaged (7. Defects).

4. Processing

Processing waste often comes hand-in-hand with 1. Overproduction and 7. Defects. It can also include things like redundant or over-attended meetings (8. Unused talent) and excessive or inefficient paperwork and data entry. If you are asking your foremen to enter the same information into more than one place, they’ll be wasting time they could be using on providing real value.

5. Motion

While transportation waste is the unnecessary movement of products and materials, motion waste is the unnecessary movement of people (or equipment). One simple example of motion waste would be when you accidentally leave one of your tools on the truck and have to stop what you are doing to go retrieve it. Another example of motion waste would be wasting time  trying to track down a specific tool or part because your van is a mess.

6. Inventory

While many of the types of waste detailed in Lean Construction are fairly clear when you take a second to think it through, inventory is a little more counterintuitive. Having a lot of inventory on hand seems like it would make sense: in accounting, inventory is considered an asset, and you do not want to worry about running out of materials. Too much inventory is wasteful though: it takes up space, costing money to store. It also gets in the way and needs to be moved around (3. Transportation). While it’s getting in the way it can also be damaged (7. Defects).

7. Defects

Defects in construction are any time things need to be repaired, and can be a result of some of the other types of waste, or it can be a simple Quality Control item. Quality Control is a whole other topic that we’ll have to dive into another day, but typically the earlier in the process a defect is caught and resolved, the less damage it does: this applies to construction as well as manufacturing!

8. Unused Talent

The eighth type of waste in lean construction revolves around not taking full advantage of your team’s capabilities. Whether we are talking about your subs or your direct employees, people are more than just robots you assign tasks to. They have lots of great ideas and experience, and to ignore that is to waste their talents.

Where Can I Start Eliminating Waste?

A lot of the research in Lean Construction is centered around design and project scheduling, and is going to apply more to General Contractors and Home Builders. This will include things like Value Engineering and Last Planner Scheduling and Pull Planning. This does not mean that you need to just write off lean construction if you are not a GC, however. You can start embracing lean construction by implementing a system like 5S, by improving your quality control, and by encouraging a culture of continuous improvement at your company.

Implementing 5S

One thing that all construction companies could benefit from, from General Contractors to Carpet Installers is 5S (also a feature of the legendary Toyota Production System). 5S stands for Sort, Set, Shine, Standardize, and Sustain, and it is a framework for improving and maintaining the efficiency of your various work areas. In a construction company, this could include your shop, your office, your work rigs and the job site itself. 5S can go a long way towards eliminating excess 5. Motion. It will also be beneficial for reducing 3. Transportation, 4. Processing, 6. Inventory and 7. Defects.

• Sort: Sort involves sorting through everything in whatever work area you are in, and removing anything that you do not use. If you are not sure if you use it, you probably don’t!
• Set (in Order): This step involves organizing everything so it has a place, with the things you use most often most easily accessible.
• Shine: In 5S, shine refers to cleaning your work area and tools and keeping it clean. It also includes keeping your tools maintained.
• Standardize: Standardize is related to sorting – everything has a home – but it can also include having a standard method for everything. This could be a standardized set up for each rig, and standard clean up at the end of each day, etc.
• Sustain: One of the fundamental laws of the universe is entropy – without outside effort, things will go from a more organized state to a less organized state. Maintaining 5S will require constant effort from you and your team.

Improving Quality Control

Defects are a huge form of waste: even if your material costs are low, having to make a special trip to resolve an issue is going to have a labor cost as well as an opportunity cost. I hope to write more about the opportunity in quality control and construction, but if you invest a little more effort into quality control early in the process, you will save tons of time (and money) later.

Developing a Culture of Continuous Improvement

Always be thinking about the different types of waste, and be on the lookout for them at your shop and on the job site. Brainstorm ways to eliminate it when you find it and don’t be afraid to try out new ideas. This also relates to 8. Unused Talent. Your team has a lot of experience, and they probably have some good ideas for ways to improve your efficiency and eliminate waste as well. Don’t let that talent go unused. Give your people the latitude to implement their ideas, and encourage them to always be considering ways to improve.

The concepts behind lean manufacturing transformed the manufacturing industry, and over the last couple of decades, they’ve begun to transform construction as well. Embracing lean construction will improve your efficiency and reduce your costs, leading to the ever important increased profits. If you are interested in learning more about lean construction, check out The Lean Builder, for tons of blog posts and other resources digging deep into the principles of lean construction.