There’s a stereotype of the construction industry: pushed deadlines, ballooning budgets, stockpiled supplies gathering dust, and workers standing idly around.
The fact is, many of those delays are hard to avoid. A construction project is a machine with many (many) moving parts, and even small defects can grind everything to a halt. To function at all, everything has to be just so.
That paradigm is considered inevitable by some, but certain thought leaders in the industry have another point of view: with a radically different strategy, construction workflow can be reliable, predictable, and uninterrupted.
They call it Lean Construction.
What is Lean Construction?
You usually hear Lean Construction (LC) described as a philosophy. That’s because it’s not a simple checklist or a new tool to add to your belt.
It’s a way of thinking that flips the normal order on its head:
- Rather than clients delegating plans and specs, LC teams collaborate, advise, and manage expectations with the client.
- Rather than quoting a budget for a project, LC teams use the client’s budget to inform how the project moves ahead.
- Rather than building what the client thinks they want, LC teams discover why they want it and use their expertise to design appropriate solutions.
- Rather than managers pushing a schedule downstream, LC teams communicate pace and requirements so management can release what they need for the next step.
Let’s examine these differences more closely.
A Different Client Relationship
All good client relationships try to maximize value and minimize waste, but in the traditional model, “value” is defined as cutting cost rather haphazardly.
Lean Construction approaches the question of value by asking what the client wants and why they want it. That gives LC teams the opportunity to find better solutions suited to their budget or to shift resources toward their top priorities and away from other areas that matter less.
LC teams don’t just build; they use their expertise to advocate for the client’s best interests.
A Different Company Dynamic
In traditional construction, owners and management hand down requirements, and workers only speak up when problems arise. A complete plan and schedule are handed from the top down, and everyone else does their best even if the plan is unfeasible. Jobs are assigned to separate groups who never speak, until one job prevents another from getting done.
Lean Construction takes a more collaborative approach to avoid the flaws of that system. The input of contractors and subcontractors is taken into consideration early on to help plan the schedule and logistics. Proactive communication is required between all parties—when one stage of production lags behind or goes faster than expected, communication allows the next stage to adjust.
Last Planner System (LPS): A Different Method of Planning
Planning in Lean Construction differs in two ways: it happens in stages, and the decision-making heavily involves the individuals that will perform the work.
The goal is to build realistic timelines and remove obstacles before they arise. Here’s how it works.
Once the client’s values are understood, LC teams collaborate and identify what’s necessary to the “value stream” (in other words, to give the client what they really want).
First, the team breaks the project into smaller look-ahead schedules. Each look-ahead schedule has a defined milestone or target completion date every three to six weeks. Next, the team plans the work backward from the defined dates. Planning backwards helps everyone on the ground identify the constraints and potential hold-ups at every step, whether that’s information, materials, prerequisite steps, or manpower. Additionally, the team identifies potential problems so they can be circumvented or accounted for in the look-ahead schedules.
As work gets underway, the team holds a weekly meeting to communicate problems, needs, and scheduling changes. All trades currently working on the site are represented. These meetings hold workers accountable, provide opportunities for feedback and improvement, and keep trades updated on issues that will impact their work. As things progress, leadership can keep the project moving because they know when to release future work.
This is known as pull-planning, or the Last Planner System (LPS).
Waste Reduction with Lean Construction
Since LC teams spend so much time collaborating and planning, they are better able to reduce waste on their construction site.
The solutions for some types of waste are built into the LPS:
- Every tradesperson has expertise to offer the project. Bringing them to the table for LPS and encouraging them to participate allows you to fully use their knowledge.
- Tasks that are completed ahead of time actually represent the waste of an opportunity to get ahead. If the tradespeople for the next step aren’t available or their constraints haven’t been met, it causes downtime. Weekly collaborative meetings prevent this by allowing the next task to be released early.
- When workers are available before their materials, information, and prerequisite work, there is wait time. Just like overproduction, weekly meetings allow the team to prevent this.
- Materials that aren’t immediately useful tie up your budget and take up storage space. You also risk inventory becoming damaged or degraded during the wait. Weekly meetings allow more accurate estimates of when inventory is necessary, making “just in time” delivery possible.
- When workers, equipment, or materials are transported to a jobsite too soon, it wastes time and puts you at risk for damaged items. Like inventory acquisition, weekly meetings make it possible to schedule transportation for the appropriate time.
Other types of waste aren’t a natural part of the LPS, so LC teams must consider them in their planning:
- Tasks done incorrectly the first time have to be done again, which wastes both time and materials. Measures should be taken to get it right the first time.
- Movement that doesn’t accomplish work is just motion. Consider the layout of jobsites or the order of operations to reduce the number of trips that workers need to get materials or tools.
- Over-processing. Any work that adds no value for the client is over-processing. Be on the lookout for any features or activities that don’t actually add value—you could just be doing them out of habit. Consider whether redundancy procedures are truly necessary. And as you try to reduce other types of waste, take into consideration whether you’re causing extra labor. Find a balance.
You won’t get it right the first time, but Lean Construction stresses continuous improvement. In addition to adjustments throughout each project, you’ll take lessons on with you to the next.
The Challenges of Lean Construction
Lean Construction can be a tough transition for your entire team. LC demands a higher level of performance from all parties and no one likes change—but companies that have made the switch believe the long-term results are worth it. To help with the steep learning curve, advocates of Lean Construction recommend you set yourself up for success with professional workshops and a Community of Practice.