Scheduling

How to build a construction schedule

Break the job into activities, give each a realistic duration, link them in the order the work must happen, add procurement and inspections, then check the critical path against the contract dates before you publish it.

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.

To build a construction schedule, list every activity from mobilization to closeout, estimate each duration from crew size and quantities, connect activities with logic (what has to finish before what can start), add submittals, long lead materials, and inspections, then calculate the critical path and adjust until the finish date meets the contract. The result should be a schedule the superintendent and the subs believe, not a chart made to satisfy a spec section.

Contracts often require it. On federal fixed-price construction, for example, FAR 52.236-15 requires a schedule showing the order of work and start and finish dates for each part, submitted within five days after work begins unless the contracting officer sets another period, and progress payments can be held if it is not submitted. Private contracts usually have their own schedule clause, so read it before you start.

What you need before you start

  • The contract dates: notice to proceed, substantial completion, any milestones, and liquidated damages if they apply.
  • The estimate: quantities and labor hours by cost code. Durations should come from the same numbers the job was priced with.
  • Drawings and specs: to find work sequences, phasing, and spec sections that set schedule format or update frequency.
  • Sub input: each major sub's crew size, lead times, and how long they need for their scope.
  • Site constraints: occupied areas, work hours, laydown space, and inspection lead times from the building department.

How to build a construction schedule in 8 steps

  1. Break the work down. Build a work breakdown structure by area and then by trade. A 3-story building might split by floor, then by framing, rough-in, inspections, insulation, board, and finishes. Keep activities short enough to track, usually no more than a few weeks each.
  2. Add preconstruction and procurement activities. Submittal prep, review time, fabrication, and delivery for anything with a long lead time. Switchgear, elevators, rooftop units, and storefront often drive the job before a shovel moves.
  3. Set durations from quantities. Duration equals quantity divided by crew production per day. If the estimate carries 960 labor hours for framing and the framer runs a 6-person crew at 8 hours, that is 20 working days. Do not guess when you have the numbers.
  4. Link activities with logic. Most links are finish-to-start: board cannot hang until the inspection passes. Use start-to-start with a lag where trades can overlap, such as painting following drywall finish one floor behind.
  5. Add inspections and owner activities. Inspections, owner-furnished equipment, design decisions, and utility connections often sit on the critical path, and they are outside your crews' control.
  6. Calculate the critical path. Run a forward and backward pass to find the longest chain of linked activities. That chain sets the finish date. See critical path method explained for contractors.
  7. Compare to the contract and fix gaps. If the calculated finish is late, look at overlapping trades, adding crews, splitting areas, or speeding up procurement before you cut durations you cannot meet.
  8. Review with the field and the subs, then baseline it. Walk the schedule with the superintendent and major subs. Once it is agreed and accepted, save it as the baseline schedule. Every later update is compared to it.

Worked example: a 14-week tenant improvement

Say a general contractor has a $480,000 office tenant improvement, 9,000 SF on one floor, with substantial completion due 14 weeks after notice to proceed. The first pass at the main path looks like this.

Example: first-pass schedule for a 9,000 SF office TI
ActivityDurationDepends on
Submittals and HVAC unit procurement8 weeksNotice to proceed
Demo and layout1 weekNotice to proceed
Framing2 weeksDemo and layout
MEP rough-in3 weeksFraming (start 1 week after framing starts)
Rough inspections1 weekMEP rough-in
Board, tape, and finish3 weeksRough inspections
Paint, ceilings, flooring3 weeksBoard finish
HVAC unit set and startup1 weekProcurement and ceilings in progress
Trim out, final inspections, punch2 weeksFinishes and HVAC startup

Running the logic, the field path is demo (week 1), framing (weeks 2 and 3), rough-in overlapping into weeks 3 to 5, inspection week 6, board weeks 7 to 9, finishes weeks 10 to 12, trim and punch weeks 13 and 14. That just hits 14 weeks with zero float. The HVAC unit arrives at week 8 and has slack, so it is not critical yet. With no float on the field path, the PM looks for room: splitting the floor into two areas lets board start in area A while area B finishes inspection, which pulls about a week out. Now the schedule has a week of float before the contract date.

One more check before calling it done: the calendar. Decide whether durations are in working days or calendar days, block out holidays and any owner shutdown periods, and set a separate calendar for exterior work if the season matters. Contracts usually state completion in calendar days, while crews think in working days. Mixing the two is a quiet way to lose two or three weeks on paper. For outdoor activities, see how to handle weather delays in the schedule.

Which scheduling format to use

A bar chart or Gantt chart is fine for small residential jobs and simple TIs, as long as the bars are linked so a change moves everything downstream. Larger commercial and most public jobs need a logic-driven CPM schedule, and the spec may name the format and update frequency. Whatever the format, crews work from a short look-ahead schedule pulled from the master, covered in how to make a three-week look-ahead schedule.

Mistakes to avoid

  1. Building the schedule without the superintendent. If the field does not believe it, nobody follows it.
  2. Leaving out submittals and procurement, then discovering the critical item is a switchboard with a long lead time.
  3. Using durations that do not match the estimate's labor hours.
  4. Typing dates in instead of using logic links, so nothing moves when one activity slips.
  5. Hiding contingency inside every activity. Show it as float or a separate buffer so you can track it.
  6. Forgetting closeout. Punch, final inspections, commissioning, and the certificate of occupancy take real time.

Templates, terms, and tools

A construction schedule template gives you the activity list, durations, and logic columns to start from. Pair it with the three-week look-ahead template for the field. Related terms: critical path method, construction schedule, and long lead items. Next, read how to sequence trades and how to update the schedule every week.

Smart Business Automator keeps the schedule, submittals, shipment tracking, and daily logs on the same job record, so a late delivery or a failed inspection is visible next to the activities it affects. See construction workflow automation.

Frequently asked questions

How detailed should a construction schedule be?

Detailed enough that each activity has one responsible party and can be tracked week to week. On most commercial jobs that means activities of a few days to a few weeks, broken down by area and trade.

Who builds the construction schedule?

Usually the project manager or a scheduler, with the superintendent setting sequence and durations and major subcontractors confirming their crew sizes and lead times.

What software do contractors use to build schedules?

Small jobs are often scheduled in spreadsheets or simple Gantt tools. Larger and public jobs commonly use CPM scheduling software, and the contract spec may require a specific format for submissions.

When is the construction schedule due?

It depends on the contract. Federal fixed-price construction under FAR 52.236-15 calls for a schedule within five days after work begins unless the contracting officer sets another period. Private contracts set their own deadline, often before the first pay application.

Sources

  1. Acquisition.gov: FAR 52.236-15 Schedules for Construction Contracts
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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