Construction Subcontracting — Spain: Ley 32/2006, Libro de Subcontratación and REA (Odoo 19)

What this module does not do, and why

It withholds nothing from the payment, because Spain has no withholding. A full-text search of Article 42 of the Estatuto de los Trabajadores returns no occurrence of "retención", "retener" or "descuento". The Spanish mechanism is not withholding at source: it is a certificate that grants exemption. A module that made you withhold 15% from a Spanish subcontractor would take from them a sum that nothing authorizes you to take.

What the regime places on the principal contractor is heavier and less visible: it will pay someone else's debt if it does not hold the right documents on the day it pays.

The three rules that block a payment

1. The specific certificate, a rolling twelve months, and a named payer. Article 43.1 f) of Ley 58/2003 (General Tributaria) makes the principal contractor secondarily liable for the taxes its subcontractor was required to pass on or withhold — VAT invoiced, withholdings on its workers' wages. This liability “no será exigible” if it holds a specific certificate issued “durante los 12 meses anteriores al pago de cada factura”.

Two pitfalls, and the module handles both. The window is reassessed with every invoice — it is not a validity you invoke once and for all. And the certificate is issued by name: “deberá hacerse constar la identificación completa del pagador para el que deba surtir efectos” (art. 126.3 of Real Decreto 939/2005). A certificate obtained by another contractor does not cover you at all — and the module says so explicitly rather than letting it through.

2. REA registration, assessed at the payment date. The subcontractor must be registered in the Registro de Empresas Acreditadas (art. 4.2 b) Ley 32/2006); the principal contractor must verify it (art. 7.1); failure to exercise this diligence makes it jointly and severally liable for the wage and social security obligations arising from performance of the contract (art. 7.2). Registration is valid for three years, and a registration that is not renewed is “automáticamente cancelada” (art. 6.1 RD 1109/2007): the number stays on the record, but the coverage is gone. The module calculates the expiry date and the six-month renewal window.

3. The Libro de Subcontratación, and the contract missing from it. A paid contract must have been recorded in an authorized book. Not having the book on site is a leve (minor) infringement (€45 to €2,450); not keeping it “en orden y al día” is a grave (serious) infringement (€2,451 to €49,180).

The Spanish register

The module keeps the duplicate of the Libro de Subcontratación, column by column in the order of the model in Annex III of Real Decreto 1109/2007: sequence number, subcontractor and NIF, subcontracting level, sequence number of the ordering party, start date and planned duration, purpose of the contract, person in charge of directing the works and workers' representatives, delivery of the safety plan and planned number of workers, reference of the coordinator's instructions and collective agreement code, signature, approval by the dirección facultativa, completion of the works.

The official book remains a physical object: A-4 format, ten numbered carbonless pages in duplicate, sealed by the contratista, authorized by the labor authority of the jurisdiction where the work is carried out — not that of the head office. The state standard makes no provision for an electronic medium. What the module keeps is therefore the duplicate that makes copying possible, not a substitute.

Subcontracting levels, and the only exception that exists

Three tiers below the contratista: “el tercer subcontratista no podrá subcontratar” (art. 5.2 d). A fourth remains possible “excepcionalmente”, but only when approved in advance by the dirección facultativa (the project's technical management) — not by the authorities — and provided that “la causa o causas motivadoras de la misma” are entered in the book (art. 5.3). The module refuses the entry until the cause is written down, and reminds you that the extension must be notified to the labor authority within five business days.

Two statuses prohibit subcontracting whatever the tier reached: the trabajador autónomo (self-employed worker, art. 5.2 e) and a subcontractor whose productive organization consists essentially of supplying labor (art. 5.2 f). The exceptional extension is not available to them, “salvo que la circunstancia motivadora sea la de fuerza mayor”.

Lifting by waiver

None of these blocks is insurmountable, and none can be overridden silently. Overrides are reserved for the subcontracting manager, require a written reason, record who made the override and when, and post the list of overridden blocks to the payment's chatter. An override that cannot be traced is not an override.

What the module does not claim to know

• The validity period of the REA registration certificate itself is not written anywhere. RD 1109/2007 reasons in terms of an application window — the month before work begins — and the scope of the exemption — the duration of the contract, for a single site. The module therefore sticks to the validity of the registration, which is written down: three years.

• The national standard provides for no electronic format of the Libro. Some autonomous communities offer one in practice; this could not be verified from a primary source and is therefore not asserted anywhere.

• No automatic connection to the REA or the Agencia Tributaria: the document is entered manually, with its source, its reference and its Código Seguro de Verificación.

Sources

Consolidated texts from the Boletín Oficial del Estado, consulted on September 14, 2026: Ley 32/2006 (BOE-A-2006-18205), Real Decreto 1109/2007 (BOE-A-2007-15766) and its Annex III, Estatuto de los Trabajadores (BOE-A-2015-11430), Ley 58/2003 General Tributaria (BOE-A-2003-23186), Real Decreto 939/2005 Reglamento General de Recaudación (BOE-A-2005-14803), RDLeg 5/2000 LISOS (BOE-A-2000-15060).