Disruption claims fail more often than any other head, and almost always for the same reason: the records do not allow the loss to be shown. The records in question are ordinary site records, which makes it a preventable failure, and establishing what exists is where loss and expense claim preparation starts.
The honest position is that some disruption cannot be proved after the event, whatever was suffered. Knowing that early changes what a claim should attempt.
What has to be shown
That an activity was carried out less efficiently than it should have been, by how much, and because of what.
Each of those three is a separate question and a claim needs all three.
Most claims establish the third and assert the first two, which is the wrong way round.
Resource allocated to activities
Labour and plant recorded against activities rather than against the project is the single most valuable record for this purpose.
It allows resource input to be compared with work output, which is what productivity means.
A weekly allocation is usually enough. Daily is better and rarely available.
Output achieved
Quantities of work completed, by activity, by period. Without this, resource records show cost but not efficiency.
Interim valuation records sometimes serve, where they are measured rather than assessed as percentages.
Percentage complete assessments are too coarse for a disruption calculation and will be challenged as such.
The sequence as planned
The programme at the point work started, so that the intended sequence is established.
Without a baseline programme there is nothing to compare the actual sequence with.
A programme produced after the event for the purposes of the claim carries much less weight, and assessors recognise one.
The sequence as worked
Site records showing when each activity actually started, stopped and restarted.
Progress records, site diaries and short interim programmes all serve this purpose.
The pattern of starting and stopping is frequently the clearest evidence of disruption, and it costs nothing to record.
The cause
Instructions, information released late, access restrictions, variations issued during the activity: each dated and each linked to the activity it affected.
Contemporaneous correspondence raising the difficulty at the time is worth more than any later analysis.
A claim where the difficulty was never mentioned until the final account faces an obvious question.
What does not work as evidence
Total cost compared with tender allowance, which shows an overspend and says nothing about its cause.
Statements from site staff about how bad it was, which are honest and not measurable.
And percentage factors applied to labour value, which are a calculation method rather than evidence of anything.
Making do with what exists
Where allocation records are missing, timesheets by gang sometimes allow a reconstruction, which is weaker and better than nothing.
Where output records are missing, interim valuations and subcontractor accounts sometimes allow quantities to be established.
Each reconstruction should be identified as one, because presenting it as a contemporaneous record is worse than the weakness it conceals.
What to do when the evidence is not there
Say so, and claim prolongation instead where the time position supports it.
Consider whether a narrower disruption claim, on one activity where records do exist, is provable.
A claim scaled to the evidence is a commercial position. One that is not gets refused and weakens everything beside it.
Starting the records now
On a live project, resource allocation and output by activity can start this week and cost almost nothing.
From the point they start, the claim becomes provable, even if the earlier period is not.
That is worth doing the moment disruption becomes likely rather than after it has run for months.
Records kept by other people
Subcontractor records are frequently better than the main contractor’s, because the subcontractor was measuring its own gangs against its own prices. Where a subcontract claim has been received, the records behind it may support the whole disruption case.
Consultant and site inspection records, held by the contract administrator or the employer’s own team, sometimes establish the sequence more clearly than anything the contractor kept. They are disclosable in proceedings and can sometimes be asked for long before that.
Which means a claim should not be abandoned on the strength of the contractor’s own file alone, and establishing what exists elsewhere belongs in the first review of the dispute rather than halfway through drafting.
Photographs, diaries and what they prove
Dated photographs establish conditions at a point in time, which is useful for access restrictions, incomplete preceding work and congestion. They do not establish productivity, and a submission that leans on them for that purpose invites the obvious answer.
Site diaries carry more weight than most people expect, provided they were kept daily and not written up afterwards. Entries recording that an activity could not proceed, with the reason, are close to the best contemporaneous evidence available.
Neither replaces resource and output records. What they do is corroborate the cause, which is the part of the claim most often disputed once the arithmetic has been accepted.
Which is why the useful question at the start is not whether the disruption happened, since on most of these projects it plainly did, but which part of it the papers will carry. That is answered by reading the records rather than by arguing about the project.
Where it fits
Establishing what records exist comes before deciding what the claim will attempt, and it takes days.
Where the records support a comparison, the measured mile is the strongest presentation available.
Keeping the records in the first place is ordinary cost control work, done during the project rather than in anticipation of a dispute.
Costs incurred that nobody has agreed to pay?
Loss and expense claim preparation sets out the contractual provisions relied on, the costs actually incurred and the link between each matter and each head of cost, in a form that can be tested.