Certifying public works is not the same as certifying private works, even though the document has the same name. Spain's Public Sector Contracts Act imposes requirements, deadlines, and parties that do not exist in a contract between private individuals.
It looks like a subtle difference. In practice, applying the process of private works to a contract with the public administration leads to rejected certifications, payment delays, and, in the most serious cases, breaches that affect the contractor's business classification.
A contractor who submits a public works certification without a valued statement of work signed by the site manager appointed by the administration, or who invoices without going through FACe, finds their payment blocked even though the work has been correctly executed.
This guide explains what the LCSP requires to certify public works, who is involved in the process, and what sets it apart from private works certification. If you first need to review the general certification process, see the complete guide: progress certifications: what they are, types, and how to issue them.
Legal framework: LCSP and the General Regulation on Public Contracts
Public works progress certifications are governed by Public Sector Contracts Act 9/2017 (LCSP), developed in the General Regulation of the Public Administrations Contracts Act (Royal Decree 1098/2001), which in its articles 147 to 166 specifically regulates the payment for works.
Added to this is Act 3/2004 on measures to combat late payment, which sets a maximum payment term of 30 days for public administrations from the issuance of the certification, as opposed to the terms freely agreed in private contracts.
Prerequisites that do not exist in private works
The contractor's business classification
To bid for and carry out certain public works, the contractor must be classified in the group, subgroup, and category corresponding to the subject of the contract, according to the State's Advisory Board on Public Procurement. Without this classification in force, the corresponding work cannot be certified.
Site handover verification record
Before starting the works, it is mandatory to draw up a site handover verification record (acta de comprobación del replanteo), signed by the site manager and the contractor. No certification is valid if the works began without this prior record, because it marks the official start of the execution period.
Site manager appointed by the administration
Unlike private works, where the developer can freely agree who supervises, in public works the site manager is appointed by the contracting administration, and they hold the exclusive power to certify the work executed.
How to certify public works step by step
Step 1: Draw up the monthly valued statement. The site manager, with the contractor's support, draws up the valued statement of the work units executed that month, at the prices of the awarded project.
Step 2: Issue the monthly certification. Based on the valued statement, the site manager issues the certification within the first ten days of the month following execution, as required by RD 1098/2001.
Step 3: Submit the certification to the contracting body. The certification is passed to the administration's contracting body for processing.
Step 4: Auditing by internal control. Unlike private works, the certification passes through an internal control check (auditing of public spending) before payment is authorised.
Step 5: Electronic invoicing through FACe. The contractor issues the corresponding electronic invoice through the general entry point for electronic invoices (FACe), mandatory for relations with the public sector.
Step 6: Payment within the legal term. The administration must pay the certification within a maximum of 30 days from its issuance, according to Act 3/2004.
Price review in public contracts
For long-duration works, the LCSP allows price review to be applied when the contract expressly provides for it and the requirements of article 103 of the act are met (among others, that at least two years have passed since the contract was signed and at least 20% of the amount has been executed). This review adjusts the certified amount according to official polynomial formulas, something that does not exist as such in private contracts.
Differences from private works certification
- Who certifies. In public works, the site manager is appointed by the administration; in private works, they are chosen by the developer or agreed contractually.
- Payment term. 30 days by law in public works (Act 3/2004); in private works it depends on what is agreed, typically 30–60 days under the LOE.
- Additional control. Public works pass through internal control auditing before payment; private works do not have that administrative filter.
- Invoicing. Mandatory through FACe in public works; free in private works, subject only to general invoicing rules.
- Price review. Regulated and limited by the LCSP in public works; in private works it is freely agreed in the contract, if included.
How Trowel helps
| Problem | How Trowel solves it |
|---|---|
| Public works certifications rejected for lack of a valued statement or supporting documentation | The site management module links each certification to the awarded budget line item, with the measurement history always available |
| Lack of visibility over the administration's legal payment terms | Centralises issuance dates and payment tracking per certification, to detect delays against the 30-day legal term |
| Lack of coordination between public and private works managed with different processes | Lets you manage both types of contract from the same platform, without relying on different spreadsheets per project |
You can see the technical detail of each module in Trowel Academy.
Frequently asked questions
Who can certify public works?
Only the site manager appointed by the contracting administration. The contractor cannot self-certify the work executed.
What is the legal payment term for a public works certification?
30 days from the issuance of the certification, according to Act 3/2004 on measures to combat late payment in commercial transactions.
Is invoicing through FACe mandatory in public works?
Yes. Invoices addressed to the public sector are processed mandatorily through FACe, the general entry point for electronic invoices.
Does price review apply to all public works contracts?
No. Only when the contract expressly provides for it and the requirements of article 103 of the LCSP are met, such as having executed at least 20% of the amount and two years since the contract was signed.
Conclusion
Certifying public works requires meeting requirements that do not appear in a private contract: business classification, site handover record, a site manager appointed by the administration, and invoicing through FACe. Knowing these differences avoids rejected certifications and payment delays that, in public works, have a clear legal term but a longer administrative process to comply with.
If you want to control public and private works certifications from the same platform, without relying on different processes per project, request a free Trowel demo.
You may also be interested in
- Progress certifications: what they are, types, and how to issue them →
- Subcontractor certifications on site: how to measure and control them →
- How to internally audit a construction project before final handover →
- Cash flow in construction: how to manage it and avoid liquidity problems →
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