Cost estimating and bid pricing for international construction: from BOQ to management-approved tender price

A tender price should be the financial expression of an execution plan, not the sum of supplier quotations plus an arbitrary percentage. The estimate must show how drawings, specifications, BOQ items, method of measurement, construction methodology, programme, procurement strategy, subcontract scope, temporary works and country assumptions flow into direct and indirect cost. When those links are missing, management cannot distinguish a competitive price from an incomplete one.

The first layer is the estimate basis. Quantity source, drawing revision, specification reference, production method, crew composition, expected productivity, material source, equipment ownership or rental assumption and subcontract boundary should be recorded. A rate that cannot be traced back to its assumptions is difficult to challenge during bid review and almost impossible to defend when the project team later asks why actual cost differs from tender cost.

The second layer is execution cost. Labour, equipment, materials and subcontractors form direct cost, while site establishment, supervision, temporary facilities, engineering support, quality, HSE, testing, security, utilities, camps, offices and time-related resources form preliminaries and indirect cost. Indirect cost should be linked to the project duration and work-front strategy; compressing or extending the programme changes more than labour productivity alone.

The third layer is international commercial exposure. Freight, customs, duties, import procedures, origin restrictions, currency, escalation, insurance, bonds, guarantee collateral, financing, advance-payment structure, retention and working capital can materially change the price without changing a single cubic metre of concrete. These costs should remain visible as separate estimate layers so management can test them rather than burying them inside unit rates.

Risk should then be separated from base cost. Ground uncertainty, quantity growth, supplier exclusions, interface gaps, Employer dependencies, permit delays, logistics disruption and schedule exposure should be assessed by probability, consequence, controllability and contractual allocation. Some risks belong in a measured allowance, some in contingency, some require clarification or qualification, and some are too open-ended to price responsibly and may affect the bid/no-bid decision.

The final management review should reconcile the estimate against benchmarks, supplier and subcontract quotations, key quantities, cash flow, major sensitivities and expected margin. The approval question is not only 'is the price low enough to win?' but also 'which assumptions must remain true for this price to be executable?' A controlled tender price therefore includes an assumption register, risk register, sensitivity cases and clear management decisions on contingency and margin.