Legal Q&A · Construction & Development

We built without a building permit in the 1990s. Can the building still be legalised?

Law as at 29 August 2026

Short answer

Usually yes. On the owner’s application, the building authority reviews a building erected and used without permission between 1 January 1990 and 31 March 2025 and, if statutory conditions are met, issues a decision with the effects of occupancy approval. Applications are possible only until 31 March 2029, and the conditions are substantive: if they are not proved, the authority orders demolition. It is therefore worth assessing prospects before approaching the authority.

An extension from 1994, a workshop completed without paperwork, a house built on the basis that “the permit will be sorted out later”. Buildings from the 1990s and later are not covered by the statutory amnesty for pre-1990 buildings, but they have their own route: a review of fitness for use under § 140d of Act No. 50/1976 Zb. It is time-limited and not automatic.

Which buildings qualify for review?

The procedure covers buildings erected and used without the building authority’s permission, or contrary to it, between 1 January 1990 and 31 March 2025 (§ 140d(1) of Act No. 50/1976 Zb.). It results in a decision confirming the building’s fitness for use, with the effects of an occupancy approval decision. The building thereby ceases to be unauthorised, with all the associated consequences, including a route to the Land Register. Advertising structures are the only exception: the procedure does not cover them.

What must be proved?

Section § 140d(1) sets several cumulative conditions: the building’s technical condition and equipment must meet the basic requirements for buildings and the purpose for which it has been continuously used, and the authority must establish that it does not endanger life. You must also own the land or have another right to it, and the land’s legal position must be settled. The building must not conflict with binding spatial-plan rules or protected interests; the rules at the time of construction or those applicable today are assessed, whichever is more favourable to you. Finally, the building must not stand beneath power lines, in their protection zone, in a flood inundation area, or in a protection or safety zone of gas infrastructure, unless the operator of the affected infrastructure consents to its location. Supporting documentation, including binding opinions from consulted authorities, accompanies the application; the authority may also request as-built documentation.

The deadline is strict

The owner of a building may submit an application for a review of its fitness for use under paragraphs 1 and 2 by 31 March 2029.

— § 140d(3) of Act No. 50/1976 Zb. (unofficial translation)

After that date, the opportunity expires whether the owner is an individual, a municipality or the state. Applying also carries risk: if compliance with the conditions is not proved, the authority will not simply leave the matter but will order demolition. It therefore makes sense to check land rights, the spatial plan and protection zones before filing: precisely the issues on which applications fail.

If the authority is already dealing with the unauthorised building

If the building authority discovers the unauthorised building itself, it opens demolition proceedings and calls on the owner to submit an application for a fitness-for-use review or retrospective permission within a period of at least 60 days (§ 88a(1) of Act No. 50/1976 Zb.). Since Amendment No. 26/2025 Z. z., a review application can also be submitted when retrospective-permission proceedings are already under way. If the building is complete, those proceedings are discontinued after the review application is filed (§ 88a(11)). For completed buildings, review is generally a simpler route than retrospective permission.

Land registration follows legalisation

The fitness-for-use decision is the document used to register the building; registration itself is a further step with its own attachments. For older houses legalised directly by the statutory amnesty, we explain registration in our answer on registering an old building without occupancy approval.

How we can help

We assess whether the building meets § 140d and prepare the application and supporting documents through construction project coordination. If you are buying property with an unauthorised building, we identify the risk early through property legal due diligence and reflect it in the contract through property purchase.

If you have already received a request from the building authority, contact us immediately: its deadline is running, and the entire building is at stake.

This answer provides general information on the law as at 29 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. We built exactly to the employer’s design and the works are defective. Are we liable? Yes, if you failed to warn that the design or instructions were unsuitable although professional care would have revealed this. The defence “we followed the design” is not enough: the Commercial Code exempts a contractor only where it warned the employer, who then insisted in writing on using the items or instructions. Work must be suspended as necessary until the employer decides. A provable warning and the employer’s written insistence are therefore crucial; the site diary is the natural place to record them.
  2. Do we have to arrange supervision by the designer during construction? And what about the architect’s author’s supervision? Yes. The Building Act obliges the builder to arrange design supervision by the designer while the building is being constructed, and continuous supervision in the case of reserved buildings. Alongside it, the author of the architectural work has its own entitlement to carry out author’s supervision, even where the building design is prepared by another designer. The Act does not, however, say to what extent and for what fee the supervision is carried out; that must be set out in the contract with the designer and with the architect.
  3. The architect has delivered a study that does not match our brief. Do we have to pay for it? It depends on whether there is a defect within the meaning of the Act. A study is defective if it does not match the result specified in the contract, for example the capacity, the intended use or the number of variants in the brief. In that case you have remedies for defects and the defects must be notified without undue delay. If the architect kept to the brief and you simply dislike the solution, that is no defect and as a rule you must pay the price.
  4. Who is to arrange the surveying, the ground surveys and the network statements for the design: we, or the designer? Unless the contract provides otherwise, they are arranged by the builder. The Building Act requires it to arrange the surveying data, engineering-geological and other surveys, statements of the consulted legal persons and cooperation with the designer. The designer is, however, responsible for determining the scope of the surveys and measurements that the design requires. The contract with the designer should therefore say expressly who procures what, who pays for it and how this affects the deadlines.

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

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