Month: May 2023

Short answer: Just-in-time (JIT) delivery in construction doesn’t mean zero inventory. It means bringing materials to the zone right before the crew needs them, in a flow (ideally a Takt plan), straight from the vendor or through a lay-down yard, with a small material inventory buffer.

Just-in-time material delivery gets a bad rap in construction sometimes. People usually think it means:

1. Only bringing materials from the vendor exactly when you need them.
2. Keeping no inventory onsite.

But this is not the case.

What does just-in-time delivery mean in construction?

Just-in-time material delivery is THIS in construction:

1. Bringing materials to the zone on the project just-in-time for the work.
2. In a flow, preferably according to a Takt plan.
3. From the vendor directly or from the vendor through a lay-down yard.
4. With material inventory buffers.

Direct from the vendor vs. through a lay-down yard

If you bring materials directly from the vendor, like when you order…

• Drywall
• Screws
• Wood supplies
• Concrete
• Other readily available items

You have the following steps in the value stream:

a. Finish material goods.

b. Load materials.

c. Transport materials.

d. Offload materials.

e. Transport to zone.

If you bring it through a lay-down area, like when you order…

• Curtainwall
• Electrical gear
• Elevators
• Other long-lead items

You have the following steps in the value stream:

a. Finish material goods.

b. Load materials.

c. Transport materials to the lay-down yard.

d. Offload to the lay-down yard.

e. Maintain materials in inventory.

f. Re-load materials for transport.

g. Transport to the building and zone.

h. Offload materials.

i. Transport to the zone.

So, bringing it directly to the site has fewer steps and saves more money, but sometimes using a lay-down yard is necessary. The most important part of JIT in construction is to not bring it to the zone until you need it. If you do, you will slow down production. People get in trouble when they prioritize reducing those extra steps over keeping the project clean and clear. Most of the time it is better to add those steps and use a lay-down yard over clogging up the project site by staging too many materials at the place of work.

So:

• No stocking the entire floor or project all at one time.
• No stocking before it is needed.
• No leaving items around for other contractors to trip over.

How do you run JIT deliveries on a jobsite?

Remember to follow these steps:

1. Always create a flowable schedule that can be used to schedule materials to the project site JIT.
2. Always manage that procurement with a log or on your schedule.
3. Always include a material inventory buffer into your supply chain duration so you can acquire enough materials to keep the project fed. A material inventory buffer is a buffer of a certain amount of materials that you keep on hand for a specified amount of time ahead of the work so you do not have too much inventory to cause waste, but enough to feed the work.
4. Always intentionally decide how materials are to be brought to the site according to your systems. Always bring them according to zones, not phases or buildings.

What should you never do with JIT deliveries?

As we close, please remember these things you should NEVER do:

1. Never schedule materials according to a schedule without trade flow.
2. Never only bring materials from the vendor to the project site. You must engage a lay-down yard when needed.
3. Never order materials without a material inventory buffer.
4. Never order your materials batched. Order them by zone.

If you begin practicing JIT materials deliveries by zone, according to a flow, you will certainly increase your production.

Want your team to plan deliveries by zone? Join our Takt Production System Masterclass or talk to us about consulting.

FAQ

Does just-in-time mean no inventory on site?

No. Keep a small material inventory buffer so the crew never runs out, but don’t stock a whole floor ahead of the work.

When should you use a lay-down yard?

For long-lead items like curtainwall, electrical gear and elevators, or when the site can’t hold material without clogging the work zones.

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