Lean construction: principles, techniques and how to start

Lean construction is a way of planning and managing building projects that applies lean thinking to design, supply and site work. It aims to deliver more value to the client while cutting waste, waiting and rework.

This guide explains the principles of lean construction and the wastes found on a building site. It then covers the main techniques, including the Last Planner System and takt planning. It ends with a practical way to start on one project.

Key takeaways

Lean construction treats a project as a flow of work between trades, not a set of separate tasks.

The idea dates to Lauri Koskela's 1992 report, and the Lean Construction Institute was founded in 1997.

The Last Planner System makes weekly promises reliable by planning backwards from milestones and checking readiness first.

Start with one project, one weekly planning routine and a short daily huddle.

What is lean construction?

Lean construction is the application of lean production ideas to the design and building of facilities. The focus is on value for the client and on smooth flow of work from one crew to the next.

Traditional site management often pushes work forward on a fixed schedule whether or not crews are ready. Lean construction asks instead what each crew needs to start, and whether that is in place.

The same logic sits behind lean methodology in factories. Construction differs because every project is a one-off, the site changes daily, and many firms share the work.

Where did lean construction come from?

Lean construction began in the early 1990s, when Finnish researcher Lauri Koskela published a 1992 report on applying the new production philosophy to construction. The report argued that building should be seen as flows of materials, information and crews, not only as conversion activities.

Glenn Ballard and Greg Howell then developed practical methods, most notably the Last Planner System. They went on to found the Lean Construction Institute in 1997.

Both strands draw on the Toyota system. For the wider background, see lean thinking and the Toyota Production System.

What are the principles of lean construction?

The principles of lean construction follow the general lean principles: define value, reduce waste, improve flow and keep improving. In building, they usually take a more specific form.

Teams define value with the client before design is fixed. They make work visible, release work only when it is ready, and involve the people who do the work in planning it.

They also try to reduce variation in how work arrives at each crew. A drywall team that never knows when the rooms will be ready cannot plan its labor.

What are the eight wastes on a building site?

The eight wastes apply on site just as they do in a factory. Each has a recognizable form in construction.

Defects are rework, such as a wall opened up to fix a missed pipe. Overproduction is building or ordering ahead of need, such as prefabricating items the site cannot yet install.

Waiting is a crew standing idle because the previous trade has not finished. Non-utilized talent is skilled workers whose ideas on sequence and safety are never asked for.

Transportation is moving materials more times than needed, for example restacking boards because the laydown area is badly placed. Inventory is surplus materials that block access or get damaged.

Motion is walking to a distant tool store or searching for drawings. Extra processing is approvals, paperwork or finishes that the client does not value.

How does the Last Planner System work?

The Last Planner System is a layered planning method. It turns a master schedule into weekly commitments made by the people who will do the work. It was developed by Glenn Ballard and Greg Howell.

It starts with a master schedule of milestones. The team then holds phase planning, also called pull planning. Trades work backwards from a milestone, placing sticky notes on a wall to show what each needs from the others. This follows the logic of a pull system.

Next comes the lookahead plan, usually covering several weeks. Here the team checks that design information, materials, access and permits will be ready, and removes constraints before the work date.

Finally, each crew agrees a weekly work plan with its foreman. Only tasks that are ready and achievable go on it.

At the end of the week the team calculates percent plan complete: the share of promised tasks that were finished. The figure matters less than the reasons behind each missed promise, which show where to improve.

What is takt planning in construction?

Takt planning divides a building into work zones and moves each trade through them at a steady rhythm. The rhythm is the takt time, the time each crew has in each zone.

Say a floor is split into five zones and each trade gets two days per zone. Framing, wiring and boarding follow each other in a train, and each crew moves on when its two days are up.

This only works if the work in each zone is balanced across trades. That balancing is where most of the planning effort goes, and it exposes problems early.

What are Integrated Project Delivery and target value design?

Integrated Project Delivery is a contracting approach in which the owner, designer and builder join the project early and share risk and reward. The aim is to remove the hand-offs and disputes that cause waste.

Target value design starts from what the client is willing to pay and designs to that cost. It avoids designing first and cutting cost later. Estimators, designers and builders work together to keep the design inside the target.

Both approaches need trust between firms, so they usually come after a team has some experience with simpler lean routines.

How do 5S, visual management and daily huddles help on site?

5S keeps a site safe and easy to work in. Marked laydown areas, labeled tool stores and cleared walkways save search time and reduce trip hazards.

Visual management puts the plan where everyone can see it. A wall board with the weekly plan, constraints and safety notes lets any crew check status in seconds.

A daily huddle of ten to fifteen minutes keeps the weekly plan honest. Foremen share what finished yesterday, what is planned today and what is blocked. Some teams track these routines with daily management software.

How do you start lean construction on one project?

Start with a single project and a single habit: a weekly planning meeting where foremen commit only to work that is ready. Do not try to introduce every technique at once.

A simple sequence works well. Run a pull planning session for the next milestone, add a three-week lookahead, then start the weekly work plan and the daily huddle.

After a month, review the reasons for missed tasks and pick one cause to remove. That is continuous improvement in practice. The same step-by-step approach is used in other fields, as in lean healthcare.

Frequently asked questions