From the bill of quantities to the tender amount

The bill returns the value of the measured works. From that value the works amount is built by distinguishing two components treated differently at tender.

The first is the amount of work subject to discount, on which economic operators submit their offer. The second consists of the oneri della sicurezza, the safety costs deriving from the health and safety plan, which are not subject to discount: they are quantified by the contracting authority and paid to the contractor in full.

To this distinction the code adds a further obligation. Article 41 paragraph 14 requires the contracting authority to quantify and state labour costs separately in the tender documents. On the bidding side, the economic operator must state personnel costs and its own safety costs separately. This is a separation of both accounting and disclosure that feeds back into how the bill needs to be organised upstream.

The quadro economico places the works amount within the total cost of the project. Alongside the works sit the somme a disposizione, the sums retained at the authority's disposal, covering items not entrusted to the works contractor: professional fees, taxes, utility connections, any land acquisition, contingencies and provisions.

The reference structure is that of the costs defined in article 5 of Annex I.7 to the code, as supplemented by Legislative Decree 209 of 2024. Established professional practice sets the document out in four columns, separating pre tender from post tender amounts: the pre tender column is completed on the basis of the figures deriving from the bill of quantities, while the post tender column is populated progressively according to the awards made and the costs actually incurred.

The quadro economico does not end with design approval. It follows the project through to closure, recording the tender discount, any variations, savings and reinstatements. The separation between pre tender and post tender columns serves exactly this purpose: keeping the gap between what was forecast and what is being spent visible, without losing the original reference.

For the designer this means the quality of the bill has effects reaching well beyond the tender. A bill built on solid quantities and consistent rates produces a cost framework that holds, with contingency margins that remain genuinely available for contingencies. A weak bill consumes those margins before the site reaches its critical phase.

The discount offered by the successful bidder does not alter the bill, but it affects everything that flows from it. The unit rates in the schedule attached to the contract are applied reduced by the discount percentage offered, and executed work and any variations are valued on that basis. Non discountable components, by contrast, continue to be recognised in full.

In the cost framework the discount frees resources, and their destination is not a matter of indifference. Savings arising from the tender fall within the authority's disposal according to the rules applicable to the project and its funding, and must be recorded in the post tender column alongside the awards made.

One point of attention remains for the designer. A high discount is never a neutral gain: if it stems from a generous estimate it signals a poorly calibrated bill, and if it stems from an aggressive bid it foreshadows tension over new rates and reservations during construction. In either case, reading the discount against the quality of the original estimate is useful information to retain for subsequent projects.

Private work has no statutory cost framework, but the logic of the three levels holds and is worth keeping explicit. A private client shown only the bill total tends to read it as the final cost of the operation, disregarding professional fees, charges, connections and taxes. Presenting a budget structure that separates works, sums at the client's disposal and contingencies is the most effective way to avoid the classic dispute over the gap between quotation and actual spend.