Checking claimed quantities: the design schedule and the survey

Updated: 2026-08-13 · ISKRIT

A claim can be wrong in two different ways, and they need two different checks. Either it does not match what was agreed, or it does not match what is on the ground. Passing the first check says nothing about the second.

Check one: against the schedule

Line by line, does the claimed quantity exist in the agreed schedule, in the same unit, within the agreed total. This catches the ordinary problems: quantities claimed above the contract quantity with no approved variation, items that appear in the claim but not in the schedule, units switched between area and volume, and the same work claimed under two descriptions.

It is mechanical and it should be automated, because the failure mode is volume rather than subtlety. On a schedule of 400 lines, three overclaims of a few percent each are invisible to a reader and obvious to a comparison.

Check two: against the ground

For earthworks the schedule check is not enough, because the quantity is not an item that exists or does not: it is a volume that has to be measured. The usual practice, agreeing a percentage on a site walk, produces a number with no evidence behind it, and both parties know it.

An as-built survey turns it into a measurement. The surface is surveyed, the volume is integrated against the original ground or the design surface, and the result is compared with the claim. The difference is then a fact to discuss rather than a matter of opinion.

What makes the comparison fair

The third row is the one that causes disputes. A survey covering 80 percent of the area, integrated as if it covered all of it, understates the volume and the contractor is right to object. The honest output states the coverage next to the number.

Bulking, and which volume is being paid for

Excavated material swells when it is dug and shrinks when it is compacted. A cubic metre measured in the cut is not a cubic metre in the truck nor a cubic metre in the fill. Which of the three the rate refers to belongs in the contract, and a check that compares a survey volume against a claim measured in truckloads is comparing two different quantities.

The quantity reconciliation tool runs the schedule comparison line by line, and the as-built quantity check derives the volume from the surveyed surface and reports the coverage alongside it.