Legal Q&A · Construction & Development

We want to extend our flat into the loft. Is consent at the owners’ meeting enough?

Law as at 16 August 2026

Answered by , Czech and Slovak attorney, admitted to the Slovak and Czech Bars (SAK 300422 · ČAK 19654).

Short answer

No. If alterations change the size of a flat, non-residential premises or appurtenances at the expense of common parts or facilities, the person carrying out the project must define reciprocal rights and obligations in a contract with the other owners of flats and non-residential premises in the building. The contract and its amendments are registered in the Land Register, supported by documentation showing the area and location of the premises.

Adding the loft to a top-floor flat, incorporating part of a corridor, glazing a loggia or converting a drying room into living space. The owner has a building permit and neighbours’ signatures from a meeting and considers the matter settled. The Flat Ownership Act requires something else.

The building’s common parts and common facilities are co-owned in shares by the owners of flats and non-residential premises (§ 2(1)(b) of Act No. 182/1993 Z. z.). Extending a flat into them therefore changes the extent of others’ ownership, not merely how the building is used. The Act has a specific provision:

The person carrying out the construction must also define reciprocal rights and obligations in a contract for alterations that change the size of a flat, non-residential premises or appurtenances at the expense of the building’s common parts or common facilities; the contract is concluded by the owner of the flat or non-residential premises in the building (the person carrying out the construction) with the other owners of flats and non-residential premises in the building.

— § 22(5) of Act No. 182/1993 Z. z. (unofficial translation)

This is a contract under § 21, namely an agreement for construction, an internal addition or an upward extension of a building. It is concluded between the person carrying out the construction and the existing owners of flats and non-residential premises (§ 21(1)). If the contract creates only a new common part, common facility or appurtenance, all owners in the building are parties (§ 21(4)).

The contract goes into the Land Register

The contract and its amendments shall be registered in the Land Register.

— § 21(3) (unofficial translation)

Registration requires documentation clearly showing the area and location of the individual flats, non-residential premises, common parts, common facilities and appurtenances (§ 22(6)). Without it, the application will fail, and retrospective documentation is difficult once the work is complete.

What the contract must contain

The contract must identify the owners and specify the location and extent of floor areas; define and list common parts, facilities, common non-residential premises and appurtenances, including those used only by certain owners; define co-ownership shares; arrange land rights; identify the person authorised to represent the owners; and specify how construction costs are financed, including contribution shares and due dates (§ 22(1)).

A frequently overlooked consequence matters: enlarging one flat changes the total floor area of the building and therefore every owner’s share in the common parts. The share is the ratio of the unit’s floor area to the total floor area of all flats and non-residential premises in the building (§ 22(1)(c/)). The contract therefore concerns not just you and the building but a recalculation for every neighbour.

What is excluded from floor area

Floor area excludes balconies, loggias and terraces, except a terrace that is not a common part of the building (§ 2(1)(f)). Glazing a loggia therefore does not enlarge the flat’s floor area, although it affects the façade, which is a common part. Even this alteration needs arrangements with the other owners.

We explain common parts and appurtenances in our answer on what belongs to a flat.

What happens if this step is skipped?

  • Registration fails. The Land Register lacks a document supporting changes to areas and shares, so the flat remains recorded at its original size.
  • The sale stalls. Buyers and banks compare the actual position with the title sheet; a discrepancy in floor area can stop financing.
  • Neighbours can seek a remedy. Interference with co-ownership without legal title can be challenged, and the passage of time alone does not cure it.
  • You are liable for defects on sale. An unregistered conversion is often precisely the defect a buyer discovers after handover.

How we handle it

We assess whether your proposal affects common parts and which contract it requires, prepare the wording and recalculate shares, and arrange registration through contract preparation and registration applications. We can handle permitting and documentation coordination through construction project coordination. If you are buying a flat with a suspected unregistered conversion, we investigate it through property legal due diligence.

Contact us before work begins. Collecting owners’ signatures after completion is substantially harder than beforehand.

This answer provides general information on the law as at 16 August 2026. It does not constitute legal services or replace an assessment of an individual case. The details of your situation may differ. Book a consultation to discuss them.

More legal questions

All questions and answers
  1. How does an agreement to enter into a purchase contract work for flats in a development? In an agreement to enter into a future contract, the parties undertake in writing to conclude a purchase contract by an agreed date and must already agree its essential terms, especially the property and price. If one party fails to conclude it, the other may seek a court decision substituting for that party’s declaration of intent within one year, and also has a right to damages. In development projects, a reservation agreement usually comes first.
  2. As a developer, do I own the copyright in the design documentation? Design documentation is protected by copyright if it constitutes a unique result of creative intellectual activity. A technical document or its designation as design documentation does not in itself attract protection. For a protected design, the author is the designer or architect who created it through their own creative activity. Commissioning a design gives you a licence to use it for the purpose arising from the contract, not unlimited rights. Other uses, particularly building the same design again or having another designer alter it, require a specific agreement; moreover, the author’s economic rights cannot be transferred.
  3. What must a contract transferring a newly built flat contain? A contract transferring ownership of a flat must be written. Under the Flat Ownership Act, it must include in particular a description of the flat and its appurtenances, the co-ownership share in the building’s common parts and facilities and the land, arrangements for land rights, and the acquirer’s declaration of accession to building management. Ownership is acquired only through constitutive registration in the Land Register.
  4. We built a building but the Land Register has not recorded it. What usually went wrong? A document error must be distinguished from a documented change of ownership. Under § 46, the Land Register records the person named in the relevant document unless another public or other document proves a different owner. A difference between the person undertaking the building named in the permit and the current owner therefore does not automatically require correction of the old permit. If the documents contain an actual error or fail to prove ownership, however, they must be corrected or supplemented; disputed ownership may require court proceedings.

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Mgr. Patrik Tulinský, LL.M. Czech and Slovak attorney · SAK 300422 · ČAK 19654

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