Last Planner in Construction | Constraints vs Roadblocks (Make-Ready Done Right)

Constraints Versus Roadblocks: Make Ready Done Right

Here’s a distinction that sounds annoying but matters more than almost anything else in Lean construction: the difference between constraints and roadblocks. I know. You’re thinking, “Jason, why can’t we just call everything a constraint and move on?” Because if we don’t separate these terms, we will overwhelm the Last Planner System, misallocate responsibility between first planners and last planners, and fail to focus trade partners on what they can actually control.

This isn’t semantics. This is the foundation of make-ready work done right.

The Pain of Mixing Constraints and Roadblocks

Let me tell you what happens on most projects. The team sits down for a Last Planner meeting. Someone asks, “What are the constraints?” And then the list starts. Missing layout. Late materials. Design conflicts. Crew capacity limits. Code requirements. Unanswered RFIs. Fixed building locations. Permit delays. The list grows to thirty items. Forty items. Fifty items. And nobody knows what to do with it because half the list is systemic issues that first planners need to optimize, and the other half is temporary blockers that last planners need to remove. But they’re all thrown together under the word “constraint.”

So, the Last Planner meeting gets overwhelmed. Trade partners are trying to solve problems that should have been designed properly upstream. First planners are ignoring systemic issues because they think the last planners will handle it. And the scheduling software is tracking everything the same way, which means nobody knows what’s permanent versus temporary, what needs optimization versus removal, or who’s responsible for what.

The project spirals. And the team blames Last Planner for not working. But Last Planner didn’t fail. The system failed because constraints and roadblocks were never separated.

Why This Is Annoying (Even to Me)

I wish I could just call everything a constraint. Let me tell you a little story. In the book writing process, what I’ll do with ChatGPT is draft a chapter. I’ll add in a podcast transcript, the YouTube transcript, and other content that I’ve made before, like blog posts. I’ll write the chapter and add a lot more content. And I’ll say, “Hey, ChatGPT, will you please help me draft it in my voice?”

And then, typically, what we do to make it more human is we review that chapter with industry experts and their stories and comments come in. But if you’ve ever written or been an author, I’m not saying I’m a good one, but I have done a lot of books, it’s very hard to loop in other stories and other opinions. So, I say, “ChatGPT, please take the original chapter plus this reference material plus my commentary plus the review comments and loop it into one.” Literally, it does such a good job and it doesn’t hallucinate because it’s trained. Training AI is just like training an intern in my opinion. These chapters are so good. I get a little weepy at the end. I’m like, “Oh my gosh, that’s such a good chapter.” And Kate’s like, “Are you reading your own books again?” Like, it’s so silly. I’m like, “This guy really gets me. I like this guy.” It’s my own stuff. It’s super pathetic.

The reason I’m telling you the story is sometimes AI will say “remove constraints.” And I’m like, “Dang it. I can’t get AI to stop saying remove constraints instead of adjust constraints because constraints are permanent or semi-permanent. Roadblocks are removable temporary things.” And I’m so annoyed. And it’s as hard to get AI trained as it is humans. People will not get off of it because it’s hard to think about the difference between constraints and roadblocks. And I get it and I have sympathy for it. But if we don’t separate them, we’re going to be in big trouble.

The Takt Planning Visualization: Trains and Tracks

Let me show you why this matters using Takt planning. If you had a forty-thousand-square-foot floor, or sixty thousand, or whatever floats your boat, would we build that whole thing all at once like a Southwest Airlines boarding process, or would we break this up into zones and basically make sure that we had bite-sized chunks leveled by work density, not by area? You’d be like, “Yeah, Jason, that’s how construction works.”

Okay. Let’s say this is the direction we’re going. And I said, “Okay, here’s trade partner number one, trade partner number two, trade partner number three, and trade partner number four.” If I said, “Hey, this train of trades trying to go the same speed, the same distance apart, is going to move through here zone to zone to zone to zone and then off to their next phase or project,” would you say that’s correct? You’d be like, “Of course, Jason. That’s exactly right. We won’t just pile them all in there and trade stack. We’re going to run them through there like a train of trades.”

That’s Takt planning. This is probably the clearest I’ve ever been. These zones on a Takt plan are listed on the left. One, two, three, four. And these wagons become what’s in the middle. And your time is on the top. And so, when we see these wagons, like let’s say this is wagon one and it’s running through here, and this is wagon number two or task number two, you have this diagonal flow and this beautiful parallelogram. All you’re seeing is this train of trades running through zones, but in the paper format, these are your zones. And all you’re seeing is where this wagon is as it goes through here in time. And the reason you have a diagonal pattern is because you’re seeing the intersection of time and space.

That’s all a Takt plan is. If you believe in zones and if you believe in trains of trades, you believe in Takt planning. And this is the system to base everything off of for your Last Planner System, for your Lean system.

Defining Constraints: The Train and the Tracks

Now let me talk about two things. Constraints deal with your train of trades and your train tracks, which are your zones. And when you think about a constraint, you’re talking about packaging. You’re talking about Takt time. You’re talking about permanent fixtures. Let’s say that there’s a building over here. And that’s why you have to start from left to right because you have to work your way out. That’s a constraint. This is a fixed thing. Your packaging is a fixed thing. Your Takt time is a fixed thing.

You can adjust them, but you’re not getting rid of Takt time. You’re not getting rid of packaging. And you’re not getting rid of this building that’s constraining the site. Constraints deal with the system, the train of trades, or the train tracks. They are permanent or semi-permanent aspects of the system design and things that you have to deal with that are not going away but can be optimized.

Here are examples of constraints:

• Takt time and packaging decisions
• Fixed building locations or site boundaries
• Crew capacity limits
• Code requirements and regulatory restrictions
• Design coordination dependencies
• Lead times for long-lead materials

These are systemic. They’re part of the production design. They require first planner attention. You don’t remove them. You optimize around them.

Defining Roadblocks: Things in the Way

A roadblock is something in the way. Let’s say that a trade lovingly and accidentally put a bundle of plywood in the way. That’s a roadblock. Let’s say that there isn’t layout in this zone. That’s a roadblock. These are temporary removable things. They’re blockers that are ahead of the train and could stop the flow if not removed.

Here are examples of roadblocks:

• Missing layout or incomplete information
• Late material deliveries that weren’t long-lead
• Unanswered RFIs
• Incomplete inspections
• Debris or obstructions in the zone
• Permits not yet pulled

These are tactical. They’re things in the path. They require last planner and superintendent attention. You don’t optimize them. You remove them.

Why Separating Constraints and Roadblocks Matters

Here’s why this matters. And I’m almost done. If you loop roadblocks and constraints together, two things happen. Number one, the list gets so big that you overwhelm the Last Planner System. And two, you don’t properly deal with these at the right time in the first planner system, which means that we chuck over the wall to trade partners things that should have been designed properly from the beginning.

And if we don’t understand constraints, we will not know how to fix the train versus things in the way. And we will not know how to program our scheduling software to track systemic issues versus temporary blockers. And we won’t know what’s permanent versus temporary. And we won’t be able to focus the trade partners on what they should be focused on, which is temporary roadblocks. And we will not give the language to first planners so they know how to design the system for the trade partners.

There are like fifty unintended negative consequences if we don’t separate these terms.

The Manufacturing Versus Construction Difference

The reason we call everything constraints is because we all read The Theory of Constraints by Goldratt and we’re like, “Oh, it’s all constraints.” But he was talking about line manufacturing and production pods and high-mix low-volume where the product is flowing through the manufacturing line. And so, there isn’t anything in the way of the manufacturing line. It’s just all whatever your constraints or bottlenecks are.

But here’s the difference. In manufacturing, the stations are fixed and the product flows. All you have is constraints. In construction, the product stays stationary and the trades move. So now you have another component. You have constraints in the system and things that can be in the way of the system. You have two things. You have constraints and roadblocks.

This is why construction requires a different framework than manufacturing Lean. The product doesn’t move. The workers move. And when the workers move through zones, they encounter both systemic limits and temporary blockers. If you don’t separate those, you can’t design the system properly.

Connecting This to First Planner and Last Planner

Constraints are primarily a first planner responsibility. First planners design the train. They optimize the tracks. They adjust packaging and Takt time. They plan around fixed conditions. They manage systemic limits. This happens in first planner meetings. It focuses on the design of the production system before boots hit the deck.

Roadblocks are primarily a last planner and superintendent responsibility. Last planners clear the path. They remove temporary blockers. They confirm make-ready work is complete. They communicate what’s missing. They enable the foremen to execute without interruption. This happens in last planner meetings. It focuses on clearing the environment so the train can move.

When you separate constraints and roadblocks, you give each group clarity about their role. First planners know they’re responsible for optimizing the system. Last planners know they’re responsible for clearing the path. And the trade partners know they’re focused on removing roadblocks ahead of the train, not solving systemic design problems that should have been handled upstream. If your project needs superintendent coaching, project support, or leadership development, Elevate Construction can help your field teams stabilize, schedule, and flow.

The Unintended Consequences of Mixing Them

Let me name what happens when you don’t separate constraints and roadblocks. You overwhelm Last Planner meetings with systemic issues that can’t be solved in that forum. You fail to optimize the production system because first planners think last planners are handling it. You misallocate responsibility and waste trade partner time on upstream design problems. You can’t program scheduling software to track what needs optimization versus what needs removal. You lose visibility into what’s permanent versus temporary. You can’t focus the team on the right work at the right time. You fail to create proper make-ready systems because you don’t know what make-ready actually means.

And you will not advance. You will not create the proper system. You will not lead the team properly. And you will not have the right people doing the right things if you do not separate these terms.

A Challenge for Builders

Here’s what I want you to do this week. Go to your next Last Planner meeting. When someone says “constraint,” stop and ask: “Is that a systemic limit we need to optimize around, or is that a temporary blocker we need to remove?” Force the distinction. Separate the list. Give constraints to the first planner team. Give roadblocks to the last planner team. And watch what happens.

The meetings will get sharper. The team will focus. The first planners will start designing better systems. The last planners will start clearing the path more effectively. And the trade partners will stop wasting time on problems that should have been solved upstream.

Knowing how to do this is in the book Takt Steering and Control. Knowing why we need it is in the book The 10 Improvements to the Last Planner System. These books give you graphics, problem-solving charts, and the frameworks to separate constraints and roadblocks so your system can function the way it was designed. As we say at Elevate, clarity creates capacity. Separate constraints from roadblocks and unlock the full power of Lean construction.

On we go.

Frequently Asked Questions

What is a constraint in construction?

A constraint is a permanent or semi-permanent aspect of the system that limits production but can be optimized. Examples include Takt time, packaging, crew capacity, fixed building locations, code requirements, and design dependencies. Constraints are managed by first planners.

What is a roadblock in construction?

A roadblock is a temporary blocker that stops the train of trades if not removed. Examples include missing layout, late materials, unanswered RFIs, incomplete inspections, or debris in the zone. Roadblocks are managed by last planners and superintendents.

Why can’t we just call everything a constraint?

Because mixing them overwhelms Last Planner meetings, misallocates responsibility, and prevents proper system design. First planners need to optimize constraints. Last planners need to remove roadblocks. If you don’t separate them, neither happens effectively.

How does this connect to Takt planning?

Constraints deal with the train of trades and the tracks (zones). Roadblocks are things in the way of the train. Takt planning visualizes both by showing the diagonal flow of trades through zones and exposing where systemic limits or temporary blockers disrupt rhythm.

What happens if we don’t separate constraints and roadblocks?

You overwhelm Last Planner, fail to optimize the production system, waste trade partner time on upstream problems, can’t program software properly, lose visibility into permanent versus temporary issues, and prevent the team from focusing on the right work at the right time.