Segregating an apartment in a community: you need 60% of owners if bylaws don't permit it

Key data

Wanting to redistribute surface area between two properties you own in a building seems like a private operation. But it is not. The Resolution of the General Directorate of Legal Security and Public Faith (DGSJFP) of April 13, 2026 makes clear that any segregation or aggregation of independent elements in horizontal property requires express support from the community, unless the registered bylaws authorize it without ambiguity.

The case that gives rise to this resolution: an owner in San Sebastián attempted to register a deed of segregation and aggregation of two dwellings, also modifying participation quotas, without authorization from the assembly. The registrar suspended registration. The owner appealed. The DGSJFP sided with the registrar.

What does this regulation establish?

Article 10.3 of the Horizontal Property Law establishes that the material division of apartments or premises, their segregation or their aggregation to other adjoining ones requires, when not expressly authorized by the registered bylaws, the approval of three-fifths (3/5) of total owners and participation quotas.

The resolution clarifies two critical points worth understanding well:

• Bylaw authorization must be express and specific. It is not enough for bylaws to generically allow "modifications that do not affect common property". That wording does not cover segregation operations with modification of quotas, which are a legal exception that must be explicitly provided for.
• The modification of participation quotas is an inseparable part of the operation. When a dwelling is segregated or aggregated, quotas change. This makes the operation something that affects the entire community, not just the individual owner.

In practice, this means that the Property Registry will reject any segregation or aggregation deed that does not prove one of these two things: either a registered bylaw clause that expressly authorizes the owner to perform that operation, or the assembly agreement with a 3/5 majority.

Economic and operational impact

The impact is not only legal. It has very concrete economic and planning consequences for any owner or developer planning to reconfigure units in a building under horizontal property regime:

• Time cost: Calling an extraordinary assembly, reaching the 60% quorum and documenting the agreement can take weeks or months, especially in large communities or with owners difficult to locate.
• Notary and registry cost: If the deed is already executed without prior agreement, the owner will have incurred notarial expenses that cannot be registered until the defect is remedied.
• Risk of chained operations: If the segregation was the preliminary step to a sale, mortgage or building permit, the entire process is blocked until assembly agreement is obtained or bylaw authorization is proven.
• Bylaw review: Communities that want to facilitate these operations for their owners in the future can modify their bylaws to include express authorization, but that modification also requires qualified assembly agreement.

Who does it affect?

• Owners of dwellings or premises in buildings under horizontal property regime who wish to divide, segregate or aggregate their property.
• Real estate developers operating in existing buildings with horizontal division and planning to reconfigure units.
• Investors who have acquired several adjoining apartments with the intention of merging or subdividing them.
• Lawyers, notaries and managers who advise on purchase and sale or renovation operations involving changes in the configuration of units in horizontal property.
• Property managers who must inform their communities about requirements for authorizing these operations.
• Property registrars, who must apply this criterion in the qualification of deeds.

Practical example

An owner holds two adjoining apartments in a building of 20 dwellings under horizontal property regime. He wants to demolish the party wall, unify both apartments into one and modify the resulting participation quotas. He executes a deed before a notary and goes to the Registry.

The registrar checks the registered bylaws. These include a clause allowing the owner to make "modifications that do not affect common property". The registrar, following the DGSJFP criterion, considers that clause insufficient: the modification of quotas does affect the entire community and bylaw authorization is not express for segregation or aggregation operations.

Result: registration is suspended. The owner must call an extraordinary assembly and obtain the favorable vote of at least 12 of the 20 owners, who also represent 60% of participation quotas. Only with that documented agreement can he return to the Registry and complete registration.

What should owners do now?

1. Review the registered bylaws of the community before initiating any segregation, division or aggregation operation. The relevant document is the one on file at the Property Registry, not an outdated internal copy.
2. Verify if express authorization exists for this type of operation. A generic clause about "modifications that do not affect common property" is not sufficient according to the DGSJFP.
3. If there is no express authorization, call an extraordinary assembly and submit the operation to a vote. The favorable vote of 3/5 of total owners and 3/5 of total participation quotas is needed.
4. Document the assembly agreement correctly (signed minutes, accredited quorum) before executing the notarial deed. Doing it the other way around generates expenses and delays.
5. If you want to facilitate these operations in the future, propose to the community a bylaw modification that includes express authorization. That modification also requires qualified assembly agreement.
6. Consult with a lawyer specialized in horizontal property if there are doubts about bylaw wording or about the procedure for calling and voting.

Official source

Consult complete regulation at official source

Notice: This article is for informational purposes only 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-2026-15526