Lean construction is a new way of designing production systems. More construction firms are adopting this methodology, as it maximizes value for the customer while simultaneously reducing waste.
Despite its appeal, lean construction is difficult to implement. It varies greatly from traditional construction methods, making proper execution of the philosophy and techniques challenging — especially in an environment where safety, budgets and timeframes can never be compromised.
Lean construction is based on a manufacturing approach developed by Toyota. This process is much easier to execute in the controlled environment of a factory. Thus, due to the unpredictability of construction, variations and disruptions to workflow are expected.
The complicated nature of the construction site calls for guiding principles, which help achieve lower cost, reduced construction time, increased productivity and effective project management. They’re representative of a holistic approach to the construction process. Check them out below —
Specify value
Value is defined by the customer’s needs through tools such as value management, quality function deployment and simulation. This differs from the traditional approach — where a project team is brought in merely to discuss what’s included in the build plans and specifications. Taking the time to understand the value of a project from the customer’s point of view develops trust early on. That trusting relationship is then used to provide advice and shape expectations for all stakeholders throughout the project.
Identify and map the value stream
The value stream identifies all the steps required to make a product and deliver value to the customer. These steps are called activities and can be divided into three categories —
- Problem solving task running from concept through detailed design and engineering to production launch.
- Information management task running from order taking through detailed scheduling to delivery.
- Physical transformation task proceeding from raw materials to finished products in the hands of the customer.
For each activity, the necessary labor, information, equipment and materials are defined. Any activities or resources that don’t add value are removed, and referred to as waste.
Eliminate waste
Lean construction seeks to eliminate waste as often as possible. There are eight types of waste to be considered —
- Defects: anything that is not done correctly the first time. Rework wastes time and materials.
- Overproduction: tasks that are completed earlier than scheduled, or before the next task in the process can be started.
- Waiting: workers may be ready, but the materials needed have not been delivered or prerequisite tasks have not been completed.
- Not utilizing talent: when the right person isn’t matched to the right job, talent, skills and knowledge go to waste.
- Transport: materials, equipment or workers are moved to a jobsite before they are needed.
- Inventory: materials that are not immediately used tie up budget, require storage and can degrade if they go unused.
- Motion: the distance between workers and tools or materials can create wasted motion.
- Over processing: added features or activities that have no value to the client.
Flow of work processes
Lean construction strives to achieve continuous, uninterrupted workflow. Construction should follow reliable and predictable processes due to the sequential nature of projects. Clear communication between all stakeholders is essential to creating flow. When one part of the process is completed behind or ahead of schedule, all parts of the project must adjust to avoid wasting time, motion and inventory.
Pull scheduling
At a strategic level, pull identifies the need to deliver the product to the customer as soon as it's needed. Generally, those able to best speed up the work processes are the subcontractors. Thus, they determine the schedule of tasks.
While these are the five guiding principles of lean construction, continuous improvement is an overarching theme of the methodology. At every step of the process, areas of improvement are identified, acted upon, and documented for future projects.
As more firms continue to adopt lean construction, the industry will become more service-oriented and futuristic. The results are guaranteed to be rewarding for everyone involved.
