Changing the lock of your own home does not generally require authorization from the condominium when the intervention is limited to the private mechanism, does not interfere with common parts, nor compromises security or alters the appearance of the building. According to the Civil Code, each co-owner is the exclusive owner of their unit and co-owner of the common parts, a distinction established in Article 1420. The replacement of the cylinder, keeping the door and its external appearance, normally falls under the management of access to one's own home, and there is no general obligation in these rules to request authorization from the assembly.
However, the situation changes when the architectural line or the aesthetic arrangement of the building is modified. Article 1422, paragraph 3, requires prior authorization from the assembly, approved by a majority representing two-thirds of the total value of the building. A new door, cladding, or exterior component must be evaluated for the effect it produces on the whole, and cannot be exempt merely because it is located at the entrance of a private dwelling.
The lock that controls the collective entrance of the building is part of a different reality from one that serves only one apartment. Article 1421 identifies as common the entrances, vestibules, staircases, and corridors of common use or passage to two or more co-owners. Article 1430 assigns the administration of common parts to the assembly and the administrator, so a resident should not unilaterally replace the common lock as if it were their own, nor prevent access by the remaining residents.
Within their powers, the administrator can handle the maintenance of common accesses and implement approved decisions. In emergency situations, the administrator acts and immediately convenes an extraordinary assembly to ratify what was done. In the absence or impediment of the administrator, Article 1427 allows any co-owner to take the initiative to carry out indispensable and urgent repairs on common parts, an exception that does not cover a change made merely due to personal preference. When there is a resolution from the assembly, it must be recorded in minutes, as determined by Article 1 of Decree-Law No. 268/94.
