Why does a low bid in Qardho come with hidden delays?

Critical path analysis underbidding risks in Qardho begin in the tender programme. A low bid hides delay by pricing generous output rates and showing a critical path that finishes on time. The sequence looks sound, but the durations rest on allowances the bidder cannot resource. The work then drifts off the path the client approved.

Where does a low bid break the critical path?

The programme usually survives, but the logic does not. To win the job, a bidder cuts supervision, plant hours and the number of crews, then keeps durations unchanged on paper. When the site runs one crew instead of two, the activity that was priced as parallel becomes sequential.

The critical path then moves. Foundations poured in one line instead of two push the blockwork start, and the delay lands on a trade that was never the constraint in the tender. That is how misidentified delay drivers appear: the weekly report blames the mason, while the real cause is a priced output rate no gang could hit.

Ask the estimator which output rate sits behind each activity on the tender critical path, and how many crews that rate assumes. Ask the client or engineer for labour and plant returns from a comparable recent project they can access. A site visit can show how many people actually work each day.

Which tender allowances should a Qardho client test first?

Test the long activities first, because small cuts there move the completion date most. General practice is that the few activities with the longest durations carry the most schedule risk, so confirm them against the project's specification and programme before signing.

Ask for these in writing:

• Curing and formwork striking times, with the method the bidder priced.
• Output rate per gang per day for each structural activity.
• Plant hours assumed for excavation and concrete, plus the standby allowance.
• Water supply arrangement for curing and mixing, and who pays for delivery.
• Float stated openly in days per activity, not hidden in a lump sum.

Ask the bidder how the allowances in the programme match the project's specification and the conditions stated for the site, and confirm curing periods against the specification rather than a general rule. A bidder who cannot show the link between allowance and duration has priced a programme that will move.

How do you catch the gap before work starts?

Line up the priced programme against the priced bill and look for activities that share the same date but cannot share the same crew. Two structural activities finishing the same week, with one crew listed, is the pattern to catch.

Then build a simple check. Take the three longest activities, ask for start and finish dates, and mark them on one sheet. Add the rain-affected months and the holidays the bidder allowed. If the finish moves past the contract date on that sheet alone, the bid is thin.

Ask two contractors to submit written programmes on the same scope so you compare activity durations side by side and build your own comparison. Differences of weeks on one activity show where a bidder has cut the allowance. Keep that comparison in the tender file, not in conversation.

Once work starts, record actual start and finish dates every week and re-run the critical path. The tender path is a claim; the weekly record is evidence.

What to do next

Before awarding, ask the lowest bidder to resubmit the programme with output rates, crew numbers and plant hours for every activity on the critical path. Compare those figures with records from a comparable recent project you can access. If the durations still cannot be resourced, price the difference or adjust the contract programme before signing, and check what the tender documents allow.