Month: September 2024

In this blog, I’m going to talk about what a work breakdown structure (WBS) is, how we should use it, how we shouldn’t use it, and what bearing it has on your project planning. We’ll cover some key definitions, and I know you’re going to love this content.

Every construction project is too large to manage as a single unit. Something has to organize the work into components that can be planned, tracked, executed, and confirmed complete. The Work Breakdown Structure is that organizing tool and in concept, it is one of the most useful ideas in project management. The problem is not the concept. The problem is how the construction industry applies it.

What Is WBS in Project Management?

A work breakdown structure (WBS) can be used for program management, project management, and multiple industries. Specifically, in construction, WBS is primarily used in work planning within a Critical Path Method (CPM) schedule. The WBS breaks the project into smaller, more manageable pieces of work—what I call “bite-sized” pieces—so you don’t have to manage too much at once. Typically, the hierarchy follows this order: phases, deliverables, work packages, tasks, subtasks, resource alignment, and milestones.

A Work Breakdown Structure is exactly what it sounds like: a hierarchical breakdown of all the work in a project into progressively smaller components, organized like a family tree. At the top of the tree is the whole project. One level down are the major functional areas or phases. One level below that are the components of each phase. One level below that are the work packages that make up each component. The breakdown continues until the work is divided into units small enough to be planned, assigned, tracked, and completed.

The analogy that makes this concrete is eating the elephant one bite at a time. A construction project as a whole is too large to digest. Breaking it into functional areas makes it smaller. Breaking the functional areas into phases makes it smaller still. Breaking the phases into work packages makes each piece manageable. The WBS is the structure that makes the elephant edible.

In scheduling software like Primavera P6, the Work Breakdown Structure provides the organizational hierarchy for the schedule. Activities are categorized by WBS code, which allows the schedule to be filtered, sorted, and reported by phase, functional area, or work package. That organizational capability is genuinely valuable it is much easier to review the mechanical scope, the exterior scope, or the commissioning scope when each one can be isolated from the others with a filter. The WBS gave schedules a structure that pure activity ID lists never had.

The Two Types of Work Breakdown Structure

Here is where the distinction that matters for production planning lives. There are two fundamentally different ways to organize a Work Breakdown Structure, and they produce fundamentally different outputs.

The first is a deliverable-based Work Breakdown Structure. This is the version most construction scheduling uses. The hierarchy is built around what needs to be delivered: mobilization, foundations, structure, interiors, exteriors, commissioning. Inside each phase are the specific deliverables that define that phase’s completion: structure topped out, building enclosed, air on, substantial completion. The activities in the schedule are organized around producing those deliverables in the right sequence. This approach makes it easy to track progress toward milestones and report schedule status to owners and stakeholders. It is organized around the question: what needs to be done by when?

The second is a Location Work Breakdown Structure, sometimes called an LBS or LWBS. This version organizes the hierarchy around where the work happens. The first level is phases. The second level is zones the specific locations within each phase where the work is performed. The activities in the production plan live inside those zones, and the sequence of activities reflects how the trades move from zone to zone through the building. The deliverables are embedded in the activities rather than being the organizing principle of the hierarchy. This approach makes it possible to track how the trades are flowing through the building and where each zone stands in the production sequence. It is organized around the question: where is the work happening and in what order are the trades moving through it?

A Warning About Using WBS in Construction Project Planning

When you use a WBS that structures time by deliverable, you end up with a two-dimensional schedule. In this format, the location, description, and relationships between activities are merely words in the activity description. This approach is problematic.

In construction, all scheduling or production planning should be based on time by location. With time on the top and location on the left, activities or work packages fit inside to create a 4D schedule. Here, you see time, space (XYZ), and movement in the schedule. This is how it should be.

Unfortunately, the time-by-deliverable approach has severely hurt the construction industry. Why? Because you miss critical elements like trade flow, handoffs, relationships, problems, speed, efficiencies, bottlenecks, and optimization. Without the ability to zone it properly, you can’t make the project faster without damaging trade partners.

Using a two-dimensional schedule is like performing critical surgery with just a two-dimensional view. You need a three-dimensional view, and the timing has to be right.

How a Time-by-Deliverable WBS Has Hurt the Construction Industry

Let’s break down what this detrimental WBS would look like in practice. For instance, in a construction phase, the deliverable-focused breakdown might start with site preparation, followed by excavation, utilities, foundations, footings, slab placement, superstructure, framing, and roofing. You’re essentially looking at the project from a generic, deliverable standpoint.

When you get to the roofing phase, you’d see a CPM schedule with a list of activities in waterfall logic tied together for the entire batched area—this is not how it should be done.

Why Location Beats Deliverable for Production Planning

The difference between the two structures is not academic. It determines whether the schedule can actually drive production or only report on it.

A deliverable-based WBS tells you that the interiors phase is supposed to be 40% complete by a certain date. It does not tell you which zones are ahead, which zones are behind, which trades are flowing correctly, and which trades are stacked on top of each other. It cannot show you the diagonal Trade Flow that is the heartbeat of the Takt Production System, because the activities are not organized by location. It cannot show you whether a buffer is being consumed or growing, because buffers are spatial and temporal they exist in the relationship between trades moving through zones and the deliverable-based WBS has no zones. It can produce a bar chart. It cannot produce a production plan.

A Location Work Breakdown Structure, organized by phase and zone, makes all of those things visible. The zones are the columns of the production plan. The activities are the rows. The diagonal lines of Trade Flow across the grid show which trades are moving smoothly from zone to zone and which ones are stalling. Buffers are visible as the planned spacing between trades. The path of critical flow is visible as the sequence of zones and activities that determines the phase completion date. This is production planning not scheduling. The distinction is not just semantic. A schedule manages commitments. A production plan manages flow.

How to Create a Location Breakdown Structure for a Project

What we need instead is a location breakdown structure (LBS), where the left column contains categories like foundations or superstructure, broken down by location (Zone 1, 2, 3, etc.). This location-based structure allows you to build the production plan within time and see flow, speeds, optimization, bottlenecks, and potential problems at a glance.

In a time-by-deliverable WBS, you only see a limited number of aspects of your production plan. With a location-based WBS, you unlock visibility into lean principles like one-piece flow, identifying bottlenecks, trade flow between zones, and whether zones are leveled.

Advantages of Using a Location-Based WBS vs. Time-by-Deliverable WBS

Let me give you an example to clarify. On a project with a time-by-deliverable WBS, the schedule was one of the best CPM schedules I had ever seen. Yet, we couldn’t see critical aspects like trade flow. The trades started stacking, activities were misaligned with the supply chain, and bottlenecks were hidden.

When we transformed this project to a time-by-location WBS, we color-coded the trades and suddenly saw beautiful flow. We simulated the plan, identified bottlenecks, aligned the supply chain, and gave the slowest trades additional resources. The project finished a week early, 30% of the team was promoted, and the contractor was awarded the next project without competition.

On the other hand, another project down the road, with similar conditions but without this transformation, finished 4.5 months late, lost $2.3 million, half the team quit, and they won’t work with that owner again.

How to Think About WBS in a Takt Context

In the Takt Production System, the Location Work Breakdown Structure is the natural organizing framework. The macro-level Takt plan is organized by phase and then by zone within each phase which is exactly the LWBS structure. The pull plan is built zone by zone, with trades working through one zone at a time to establish the sequence and the stagger. The norm-level production plan extends that zone-by-zone structure across the full phase. The look-ahead and the weekly work plan filter from that structure.

The deliverable is not gone from this framework it is embedded in the activities within each zone. An activity in Zone 4 for the mechanical trade partner is both a location (Zone 4) and a deliverable (mechanical rough-in complete, ready for insulation). The LWBS captures both dimensions without sacrificing either. The difference is that the location is the organizing principle, not the deliverable. That makes the production plan readable from the production perspective where are the trades, how are they flowing, what is ahead or behind rather than only from the scheduling perspective of what has been delivered by what date.

A Note on P6 and Modern Scheduling Tools

Work Breakdown Structure became a standard feature in construction scheduling software with the introduction of Primavera P6, which made it possible to build multi-tiered hierarchies and filter activities by WBS code. This was a genuine improvement over purely ID-based activity lists, which provided no natural grouping of activities and made it difficult to see the project at different levels of detail.

The limitation is that P6’s WBS implementation tends toward the deliverable-based structure by default phases, milestones, and activity groupings that reflect the contractual schedule rather than the production reality. Building a true Location Work Breakdown Structure in P6 requires deliberate configuration of the WBS hierarchy to reflect zones rather than deliverables, which most scheduling teams do not do because they are building a schedule for reporting rather than a production plan for field management. The tool can support the LWBS but the default use does not, and the gap between what the tool produces and what production planning requires is where the schedule loses its connection to the field.

Warning Signs That the Wrong WBS Is Driving the Project

Before the gap between the schedule and the field becomes a schedule crisis, watch for these signals:

• The project schedule can tell you what phase percentage is complete but cannot tell you which specific zones are ahead or behind in the production sequence.
• The schedule has activities organized by scope mechanical, electrical, plumbing rather than by location, which means Trade Flow across zones is invisible in the schedule.
• The superintendent is managing production from a separate spreadsheet or visual board because the schedule does not show the information needed to drive daily production decisions.
• The look-ahead is created by filtering the schedule by date rather than by zone, which means the look-ahead reflects what the schedule says should happen rather than what the production plan shows is ready to happen.

Every one of those signals means the WBS is organized for reporting rather than for production. The schedule is tracking commitments. Nobody is managing flow.

The Bottom Line: Why WBS Must Be Location-Based

Whether you’re using CPM scheduling or Takt planning (which is preferable), ditch the time-by-deliverable WBS. Switch to a location-based work breakdown structure. If you’re in construction, it will always need to be by location.

We are building people who build things. The teams that build their production plans on a Location Work Breakdown Structure organized by phase and zone, with Trade Flow visible and buffers deliberate are the teams whose schedules reflect what is actually happening in the field. If you need more information on this approach, check out our resources: we offer books, courses on Takt production systems, one-on-one coaching, and consulting. We’ll help you transform your project into one that uses a location-based WBS to create a real production plan—not just a wish list schedule.

A Challenge for Builders

Open your current project schedule and look at the top two levels of the Work Breakdown Structure. Is the second level organized by deliverable or milestone structure, interiors, commissioning or is it organized by location and zone? If it is organized by deliverable, the schedule can tell you what needs to be done but not how the trades are moving through the building. This week, draw a simple grid: zones across the top, trades down the side, and the planned sequence of each trade through each zone filled in. That grid a Location Work Breakdown Structure applied to the current production plan will show you information about the project that the current schedule cannot.

As Jason says, “Flow over busyness.”

Frequently Asked Questions

What is the difference between a Work Breakdown Structure and a Location Work Breakdown Structure?

A Work Breakdown Structure organizes activities by deliverable what needs to be done or produced by when. A Location Work Breakdown Structure organizes activities by where they happen which phase and which zone. The LWBS is the organizing framework for production planning because it makes Trade Flow, zone sequencing, and buffer placement visible. The deliverable-based WBS is useful for reporting schedule commitments but cannot drive production.

Why is a deliverable-based WBS insufficient for production planning in construction?

Because production planning requires visibility into where the trades are, how they are moving from zone to zone, and whether their flow is continuous or interrupted. A deliverable-based WBS shows what has been produced by what date but not how the production is happening spatially. Without zone-level organization, Trade Flow cannot be tracked, buffers cannot be placed deliberately, and the schedule cannot reveal the stacking or stalling that causes delays.

How does the Location Work Breakdown Structure connect to the Takt Production System?

The Takt Production System’s entire planning stack the macro-level Takt plan, the pull plan, the norm-level production plan, the look-ahead, and the weekly work plan is organized by phase and zone. That is the LWBS structure. Activities live inside zones, and the sequence of activities reflects how the train of trades moves through the building. The LWBS makes the Takt plan’s diagonal Trade Flow visible and trackable, which is why it is the correct organizing structure for production planning.