Key data
| Regulation | Resolution of April 23, 2026, from the General Directorate of Legal Security and Public Faith |
|---|---|
| Publication | July 24, 2026 |
| Entry into force | Not specified |
| Affected parties | Property owners with buildings in another's subsurface, notaries and property registrars |
| Category | Real Estate |
| Source | BOE-A-2026-16134 |
| Resolving body | General Directorate of Legal Security and Public Faith (DGSJFP) |
| Registry involved | Property Registry of Palma de Mallorca no. 5 |
If you have a building that occupies the subsurface of an adjacent property and want to regularize it registrally, the choice of legal figure is not free: the Registry can reject it. The Resolution of April 23, 2026 from the General Directorate of Legal Security and Public Faith (DGSJFP) makes this clear when resolving the appeal against the negative qualification of the registrar of Palma de Mallorca no. 5.
The specific case: an attempt was made to register an atypical horizontal party wall servitude to regularize a construction that invaded the subsurface of an adjacent property. The registrar suspended the registration arguing that the appropriate figure was the sub-building right provided for in the TRLS, not a conventionally created servitude. The DGSJFP analyzes the substance of the matter and establishes doctrine on the limits of freedom of will in the configuration of real rights.
What does this regulation establish?
The resolution addresses three legal issues with direct practical consequences:
| Issue | Position of the registrar | Analysis by the DGSJFP |
|---|---|---|
| Legal figure to regularize construction in another's subsurface | The sub-building right of the TRLS must be used, not an atypical servitude | Analyzes whether the registrar can impose a specific figure when typified alternatives exist |
| Scope of the numerus apertus principle | Freedom of will has limits when a more suitable typified figure exists | Examines the limits of freedom in configuring real rights |
| Distinction between legal figures | Party wall, sub-building and overextended construction are distinct figures with their own regimes | Delimits the scope of application of each figure |
The numerus apertus principle allows creating atypical real rights beyond those expressly regulated by law. However, this principle has limits: when the legal system already provides a specific figure for a concrete situation, the Registry can question the suitability of an alternative conventionally created figure.
In this case, overextended construction in another's subsurface has specific regulation in the TRLS through the sub-building right, which calls into question the registral validity of a horizontal party wall servitude established for the same purpose.
Economic and operational impact
The practical consequences of this resolution are immediate and affect operations already underway or planned:
- Blocked operations: Any deed of atypical servitude to regularize another's subsurface can be suspended at the Registry, paralyzing the real estate transaction until it is remedied with the correct figure.
- Correction cost: Changing the legal figure implies executing a new public deed before a notary, with notarial fees, registry fees and, where applicable, additional taxation for the new documented legal act.
- Risk of nullity: A registration obtained with an unsuitable legal figure can be challenged later, generating legal uncertainty about ownership and transferability of the property.
- Impact on financing: A property with irregular or suspended registral status makes it difficult or impossible to obtain mortgage financing on the property.
- Delay in transfers: Lack of complete registral registration complicates the sale or transfer of the property, as buyers and their financiers require clean registral ownership.
Who does it affect?
- Property owners whose building occupies all or part of the subsurface of an adjacent property, especially in dense urban areas or in old buildings.
- Real estate developers who intend to regularize situations of construction overextension before transferring or mortgaging the property.
- Notaries who authorize deeds establishing atypical real rights to regularize constructions in another's subsurface: they must review whether the chosen figure is the most appropriate according to DGSJFP doctrine.
- Property registrars who qualify this type of document: the resolution reinforces their power to question the suitability of the legal figure used.
- Lawyers and legal advisors who structure operations to regularize overextended buildings.
- Financial entities that analyze mortgage guarantees on properties with improperly regularized subsurface situations.
Practical example
A property owner in Palma de Mallorca discovers that the basement of their building partially occupies the subsurface of the adjacent property. To regularize the situation, they agree with the neighbor to establish a horizontal party wall servitude before a notary, which is presented to the Property Registry for registration.
The registrar of the Property Registry of Palma de Mallorca no. 5 suspends the registration because she considers that the appropriate figure for this situation is the sub-building right regulated in the TRLS, not an atypical servitude. The owner appeals to the DGSJFP, which analyzes whether the registrar can impose a specific legal figure or whether freedom of will allows choosing a conventional servitude.
The result: the DGSJFP analyzes the limits of the numerus apertus principle and the distinction between party wall, sub-building and overextended construction, establishing doctrine that affects all similar cases in Spain. Until it is resolved with the appropriate figure, the property remains with its registral situation unregularized, blocking any sale or mortgage transaction that requires clean registration.
What should companies do now?
- Audit existing buildings: Review whether any own construction occupies the subsurface of adjacent properties, especially in urban buildings with basements or parking.
- Verify registral status: Check whether the situation is already regularized registrally and with what legal figure, to assess whether there is risk of challenge.
- Consult with specialized notary: Before executing any regularization deed, confirm that the chosen figure (servitude, sub-building right or other) is appropriate according to DGSJFP doctrine and the TRLS.
- Avoid atypical servitudes without prior analysis: Do not assume that the numerus apertus principle allows any configuration: the Registry can reject it if a more suitable typified figure exists.
- Plan regularization costs: If an irregular situation is detected, budget the costs of deed execution, registry fees and taxes associated with the correct legal figure before starting the process.
- Inform buyers and financiers: If there is an unregularized subsurface situation, communicate it in due diligence to avoid problems later in the transfer or in obtaining mortgage financing.
Frequently asked questions
Can the Registry reject an atypical servitude if a more suitable legal figure exists?
Yes. According to the Resolution of April 23, 2026 from the DGSJFP, the registrar can suspend the registration of an atypical servitude when he considers that a more suitable typified legal figure exists for the concrete situation. In the case analyzed, the registrar of Palma de Mallorca no. 5 suspended the registration of a horizontal party wall servitude because she understood that the correct figure was the sub-building right regulated in the TRLS.
What is the sub-building right and when does it apply?
The sub-building right is a figure typified in the Consolidated Text of the Land Law (TRLS) that allows regularizing situations in which a construction occupies the subsurface of another's property. Unlike a servitude, it has a specific and predetermined legal regime. The DGSJFP considers that when this figure is applicable, the numerus apertus principle does not support substitution by an atypical conventionally created servitude.
What is the difference between party wall, sub-building and overextended construction?
These are three distinct legal figures with their own regimes. Party wall regulates shared ownership of dividing elements between properties. Sub-building is the right to build or maintain a construction under the soil of another's property. Overextended construction is the factual situation in which a building invades the subsurface of an adjacent property without legal title supporting it. The DGSJFP resolution precisely analyzes the distinction between these figures to determine which is appropriate in each case.
What happens if an atypical servitude is registered instead of the sub-building right?
If the Registry admits registration with an unsuitable figure, there is risk of later challenge of the registration, which generates legal uncertainty about ownership and transferability of the property. Additionally, it can hinder obtaining mortgage financing and complicate future transfers, as buyers and financial entities require a clean and correctly regularized registral situation.
What should I do if I have a construction in the subsurface of an adjacent property without regularization?
First, verify the current registral status and consult with a notary specialized in real estate law before executing any regularization deed. The legal figure to be used (servitude, sub-building right or other) must be appropriate according to DGSJFP doctrine and the TRLS. An incorrect choice can result in suspension of registration by the Registry, with the correction costs that this entails.
Official source
Consult complete regulation in official source
Notice: This article is merely informative in nature and does not constitute legal advice. For specific decisions, consult a qualified professional. Source: https://www.boe.es/diario_boe/txt.php?id=BOE-A-2026-16134