Scheduling

What is lead time in construction?

Lead time is the time between placing an order (or releasing a submittal) and the item arriving on site, ready to install. It decides when you must buy to keep the schedule.

Two construction professionals review paper plans beside a tablet at a jobsite workbench.
Plan reviews connect field conditions, drawings, and the next decisions on a job. AI-generated illustration.

Lead time is how long you wait for something after you ask for it. In construction it usually means the time from order to delivery for materials and equipment, but it often has to include the steps before the order too: shop drawings, submittal review, approval, and release for fabrication. A supplier may quote eight weeks, but if submittal review takes three more, the real lead time from your side is eleven.

Items with lead times long enough to affect the schedule are called long-lead items. Lead time is the measurement; long-lead items are the things that need special handling because of it.

How lead time fits into the schedule

Work backward from the date the item must be installed. Say a GC is building a small medical office and the rooftop HVAC units must be set on May 20, when the crane is booked.

Example: working back from the install date
StepDurationMust be done by
Set units on roof (crane day)1 dayMay 20
Delivery to siteBuffer of 1 weekMay 13
Manufacture and ship (supplier quote)10 weeksOrder by March 4
Submittal approval and release3 weeksSubmit by February 11
Prepare submittal1 weekStart by February 4

So the mechanical sub needs to start the submittal by early February, before the building is out of the ground. If nobody tracks that date, the crane gets rebooked and the roofing and interior work pile up behind it.

Lead time also matters on small residential jobs. A remodeler who lets the homeowner pick a custom vanity two weeks before the plumber's trim-out date has built a gap into the schedule. Set selection deadlines in the contract and tie each one to the lead time of the item being chosen.

What affects lead time

  • Manufacturer backlog and plant capacity.
  • Custom or made-to-order items versus stock items.
  • Submittal review cycles and resubmittals. One rejection can add weeks.
  • Shipping distance, freight capacity, and imports.
  • Owner selections that come late, common in residential work.

Common mistakes

  1. Using a lead time quoted months ago. Quotes change; reconfirm when you order.
  2. Counting from the order date and forgetting submittal time, which is often the bigger delay.
  3. Not putting lead times into the construction schedule as activities with logic ties.
  4. Assuming the supplier will call when there is a delay. Ask for ship dates and follow up, which is the job of expediting.
  5. Ordering early but having nowhere to store the material, which leads to damage or theft.

Related terms

Track actual lead times against quoted ones on every job. After a year, you will know which suppliers deliver when they say they will and which ones need a two-week cushion built into the schedule.

See procurement, submittal log, look-ahead schedule, and the guide how to manage long-lead items. Smart Business Automator tracks shipments and submittals together, so a slipping ship date shows up next to the activity it will delay; see RFI and submittal tracking automation.

Frequently asked questions

What is the difference between lead time and long-lead items?

Lead time is the waiting period for any item. Long-lead items are the specific items whose lead time is long enough to threaten the schedule.

Does lead time include submittal approval?

Supplier quotes usually start after approval. For planning, add submittal preparation and review time to get the real lead time from your side.

How do I find out an item's lead time?

Ask the supplier or manufacturer for a current quote at bid time and again at order time, and get it in writing when possible.

What can I do if lead time is too long for the schedule?

Release the order early, ask about stock alternatives, submit a substitution request, resequence work, or discuss early procurement with the owner.

Written and edited by

Maurice Francois writes and edits construction operations guides for Smart Business Automator. More from Maurice on the Scaling Legends podcast.

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