The Walkhampton barn looked, on the architect’s package, like a fairly standard conversion. The site told a different story. The east gable needed significant structural strengthening, the existing slab was on inadequate sub-base, and one of the proposed rooflights was going to need a steel that wasn’t in the engineer’s package yet.

We flagged all three in the take-off, the engineer redesigned where needed, the contractor priced the revised package, and the project went out to tender with a budget that reflected the building. None of the structural surprises became contract variations because all of them were known going in.

That is the value of a take-off you can defend.