Schedule control is not keeping a programme file tidy.
It is knowing, at any point:
- where the job actually stands against what you planned;
- what is driving the completion date;
- what you must decide now.
That is the practical purpose of project controls for contractors. You need the commercial discipline used on a major infrastructure programme, but scaled to the size and complexity of your business.
We get onto the programme early. We tell you the truth about it. We give you a plan you can act on.
Start with an agreed and dated baseline programme
Your baseline programme sets out how you intend to deliver the work. It should show the planned sequence, durations, logic, key dates, access assumptions, resources and completion forecast.
It must be agreed, dated and preserved.
Without an agreed baseline, you may still have a schedule. You do not have a reliable reference point. That creates commercial uncertainty when progress changes, delay occurs or a client instruction affects the work.
Under NEC4, the Accepted Programme is the contractual reference point for assessing change and delay. For a compensation event, the assessment normally considers the Accepted Programme current at the relevant dividing date. If your programme is late, incomplete or not accepted, the Project Manager may make its own assessment of the event’s effect.
That is why NEC contract administration and schedule control must work together.
Your baseline should not be overwritten when circumstances change. Keep the original version. Record each update, the data date, the changes made and the reason for those changes. Truth is more useful than a programme that has been quietly altered to produce a better-looking result.
Critical path and float: what they mean in practice
The critical path is the sequence of activities that determines the earliest possible completion date. There is no spare time on that route. A delay to one of those activities can move completion unless you change the sequence, resources or method.
A project can have more than one critical path. The path can also move as the work progresses. Procurement, design release, access, progress, resequencing and emerging constraints can all change the programme logic.
A critical path is not a label applied after the event. You must demonstrate it from the programme records that existed at the time.
Float is the spare time available before a delay affects a key date or completion.
- Total float is the time an activity can move without delaying overall project completion.
- Free float is the time an activity can move without delaying the early start of its successor.
Float consumption matters because it reduces your ability to absorb problems. Once all float has gone, the next delay has a direct effect on the completion forecast.
Who benefits from float? That depends on the contract, the programme and the circumstances. In practical terms, float is available within the project plan unless the contract says otherwise. It is not automatically the contractor’s private reserve or the client’s property. If one event consumes it, a later event may have less room to move without affecting completion. Record why float was consumed and by what event.
| Schedule position | What it tells you | What you should do |
|---|---|---|
| Critical activity | There is little or no spare time before completion is affected. | Monitor daily and address constraints immediately. |
| Near-critical activity | A small amount of float remains. | Treat it as an emerging risk, not as comfortable spare time. |
| Activity with total float | The activity can move without immediately moving completion. | Track float consumption and the cause of movement. |
| Activity with free float | The activity can move without delaying its immediate successor. | Protect successor activities and check downstream logic. |
An updated programme is not automatically control
A new set of dates does not explain why the dates moved.
Every update should compare the current position with the previous version and answer:
- What progress was achieved?
- Which activities started or finished later than planned?
- Which logic changed?
- What happened to total and free float?
- Has the critical path moved?
- What is now driving completion?
- What decision or mitigation is required?
A schedule update without a narrative is only a revised forecast. Control requires explanation.
The same principle applies to delay analysis and extension of time. Your delay position becomes defensible when the records show how the programme changed over time, what caused that change and what the project team did in response.
Read our guide to delay analysis and extensions of time. It explains why a delay position reconstructed at final account stage is weaker than one supported by reliable updates and contemporaneous records.
Measure work done, not effort spent
“Activity 60% complete” means very little unless your team has a consistent rule for awarding progress.
Hours spent do not always equal work completed. A crew may spend a week on an activity but achieve less physical output than planned because of access, rework, late information or poor productivity.
Set simple rules for crediting progress. For example:
- measure installed quantities where possible;
- use agreed milestones for discrete activities;
- use weighted steps for longer activities;
- record actual starts and finishes;
- support progress with inspections, photographs, delivery tickets or measurement records;
- do not credit work that has not been completed or verified.
Your site team should understand what 25%, 50% and 75% complete mean for each activity. Standardised rules give you a more reliable forecast and reduce arguments about reported progress.
Use look-ahead planning to remove constraints
The baseline tells you the intended route. Look-ahead planning tells you what must happen next.
Review the next two to four weeks in detail. Identify anything that could stop the planned work:
- drawings or technical information;
- approvals and inspections;
- access or possession;
- labour and plant;
- materials and deliveries;
- subcontractor readiness;
- permits;
- interfaces with other trades;
- decisions still required from the client or design team.
Assign an owner and a date to each constraint. Then review whether it has actually been removed.
Do not wait for the activity to become critical before dealing with it. Early action gives you choices. Late action gives you explanations.
This is a practical extension of the NEC4 early warning process. An early warning should connect to the programme, risk register, action owner and forecast effect.
Recovery and resequencing need a cost consequence
Recovery is not a line on a report saying “work harder”.
You can potentially change:
- the sequence of activities;
- resource levels;
- work fronts;
- working hours;
- construction method;
- procurement priorities;
- subcontractor deployment.
Each option has a consequence. More labour may increase cost without improving output. Resequencing may create inefficiency or additional temporary works. Additional shifts may affect supervision, welfare, plant and labour availability.
An acceleration proposal without a cost consequence is incomplete.
Test what the proposed change can realistically achieve, what it will cost and whether it introduces new risk. Then record the decision. A usable recovery plan is better than a presentation that simply promises an earlier date.
The records that protect your position
Records created as the work happens carry far more weight than reconstruction.
Maintain a proportionate, linked record set:
- dated programme submissions and progress updates;
- schedule narratives and revision logs;
- site diaries and daily progress records;
- allocation sheets and labour returns;
- plant records and standing-time records;
- delivery tickets and material records;
- weather records;
- instructions and correspondence;
- meeting minutes and action trackers;
- photographs showing progress, access and obstructions;
- access and availability logs;
- a live change, early warning and risk register.
Link records to the relevant activity or event where possible. If a design instruction affects a workfront, the instruction, programme extract, site diary, photograph, labour record and commercial assessment should tell the same story.
Our NEC4 compensation events guide explains why the programme demonstrates when an event affects the job, while the cost assessment demonstrates what that effect costs.
Illustrative scenario: float is consumed and completion moves
Illustrative only. This is not a project assessment.
Your programme shows three weeks of total float before a section of drainage work affects the follow-on surfacing activity.
A late design clarification delays the drainage start by one week. The team uses one week of float, so the completion forecast does not move.
A further access restriction delays the work by two weeks. The remaining float is consumed. The drainage activity is now driving the surfacing start and the completion forecast moves by two weeks.
The important point is not the arithmetic. It is the record.
Your updates should show:
- the original float;
- the design clarification and its effect;
- the access restriction and its effect;
- the changing critical path;
- the mitigation considered.
Without those records, someone reviewing the position later may see only a late finish and no reliable explanation.
Schedule control is the foundation for better decisions
Project controls should give you early visibility of cost, time, risk and change. Schedule control is one part of that connected system, not a monthly reporting exercise.
BHD Limited brings 25 years of experience across construction, defence and infrastructure. BHD Commercial's team brings 25 years' experience across construction, defence and infrastructure. Our team are members of the relevant professional body.
Our head office is at 66 Paul Street, London EC2A 4NA. Our regional office is at 4-5 Victoria Square, I11, Wolverhampton, WV1 1LD.
The next posts in this project controls cluster will cover:
- cost control;
- risk and contingency;
- change and configuration control;
- earned value without the jargon;
- reporting that gets used.
The aim is consistent: proportionate systems, reliable information and decisions made before they become urgent.
Frequently asked questions
What is the critical path?
It is the sequence of linked activities that determines the completion date. It can move during the job, and there may be more than one critical path. You need to demonstrate it from reliable programme records.
What is float and who owns it?
Float is spare time before an activity affects a key date or completion. Total float relates to overall completion; free float relates to the early start of the next activity. Who benefits from it depends on the contract and circumstances. Do not assume it is automatically yours or the client’s.
How often should I update the programme?
Follow the contract first. Monthly updates are common, with more frequent reviews on complex or fast-moving work. Look-ahead planning should usually happen weekly. An update is only useful if it includes actual progress, logic changes, float movement and a clear forecast narrative.
What if my programme is not accepted?
Establish what was submitted, what was rejected and why. Keep the submission trail and obtain advice on the contractual position. Under NEC, an unaccepted programme can create uncertainty because the Project Manager may assess delay or change using its own assumptions.
Can I recover lost time without extra cost?
Sometimes. You may change sequence, resources, work fronts or method. But recovery normally has a cost, risk or productivity consequence. Test it properly and record the decision. Do not present acceleration as free.
Do I need a planner?
You need someone who can control logic, progress, critical path, float and forecast movement. That may be an internal planner, a suitably trained project manager or external support. You do not need an oversized system. You do need the right discipline.
Conclusion: control the programme before it controls you
Keep the baseline intact. Update it with discipline. Explain every material movement. Measure work done rather than effort spent. Track float before it disappears. Remove constraints early. Record decisions as they happen.
Do not wait until final account to reconstruct the project history.
If you want a straight view of your programme, records or commercial exposure, request BHD Limited’s free Commercial Health Check. It is an initial conversation focused on what is supportable, what needs attention and what you can act on next.