Certifications and acceptance in Spanish public works

In works contracts, the supervising team issues monthly certificates for the executed works, built from the month's valued measurement: actual quantities of the period applied to contract prices (design prices affected by the award discount). Three legal features are worth fixing:

They are payments on account. The monthly certificate is not a partial settlement and implies no approval or acceptance of what it certifies: the definitive measurement arrives with the final certificate. This protects both parties: intermediate measurement errors are corrected later without consolidating rights.

Payment runs on a legal deadline. The administration has thirty days to pay from the certificate's approval, and breach accrues automatic late-payment interest, with no demand needed, plus the right to recover collection costs. If the delay drags on, the law provides escalating claim mechanisms and even contract suspension for prolonged non-payment.

Advances for stockpiles and equipment are possible. The documents may provide advances for stockpiled materials and for plant and equipment, secured by a guarantee, a relevant treasury tool in projects with early stockpiling of expensive materials.

Once the works are complete, acceptance (recepción) is the formal act (with minutes, in the presence of the administration, the supervising team and the contractor) by which the administration takes the works over. It must occur within one month of completion. Its effects are the heart of the close-out: the warranty period begins (set in the documents, one year being the usual minimum), the contractor's custody responsibility ends and the clock starts for the final certificate.

If the works show defects, the administration may accept them with reservations documented in the minutes, setting a period to cure, or refuse acceptance issuing precise instructions. For the contractor, the content of the minutes is strategic: reservations delimit exactly what must be cured, and everything not reserved is deemed accepted in conformity. The documentary dimension of this act, and of site minutes generally, is developed on the construction-process side in the articles on works handover and the final certificate and site minutes.

The financial close-out has two stages that should not be confused. One closes the works and the other closes the contract.

The final certificate is approved within three months of acceptance: it is the general and definitive measurement of the executed works, drawn up jointly with the contractor, where measurement differences are settled (including the excess of up to 10 per cent the law admits without a modification) and the works actually executed are balanced. The period runs from acceptance and the measurement is best prepared beforehand.

The final account (liquidación) arrives at the end of the warranty period: if the works show no outstanding liabilities, the contract's final account is approved, remaining amounts are settled and the performance guarantee is released. The financial logic of the close-out (which items usually remain open, how balances are negotiated) is common to all projects and is covered in the article on the final account.

The certificate is the final document of a monthly chain worth mastering: measurement cut-off at the agreed date, valued measurement drawn up by the supervising team, cross-check against the contractor's own measurement and issue of the certificate. The useful discussion happens before signature, over the month's quantities; afterwards, the certificate enters the administrative circuit and discrepancies wait for the next one or for the final certificate.

Three habits protect the payment flow. Keeping a parallel own measurement, item by item, and confronting it with the valued measurement every month: systematic downward differences caught early get corrected; accumulated over twelve months, they become a final-certificate fight. Recording in the monthly minutes the items executed but not certified, with their cause, so the gap does not become silently normalised. And monitoring each certificate's administrative circuit (issue date, approval date), because the 30-day payment period runs from approval, and an approval that is systematically delayed is, in practice, free financing extracted from the contractor, which is also claimable.

A project of EUR 1,047,200 (award price excluding VAT), 12-month schedule, acceptance on 30 June of the year following the start:

Milestone	Date	Financial effect
Certificates 1 to 12	Monthly during execution	~EUR 87,000/month on average, payable 30 days from approval
Acceptance	30 June	One-year warranty period starts
Final certificate	Before 30 September	Settles quantities: +EUR 38,000 for real excesses (3.6%, within the 10%)
End of warranty period	Following 30 June	No outstanding liabilities
Final account and guarantee release	After approval	The EUR 52,360 bank guarantee is cancelled

The treasury reading: months can pass between the last monthly certificate and the final one, and the guarantee stays locked for another year. The financing cost of that calendar (live guarantees, outstanding balances) belongs to the bid study as much as the unit prices do.