It is better to confirm than to remedy. When buying a property, most of the problems that turn into long and costly disputes were detectable before the deed. real estate due diligence is the legal audit that anticipates those risks while there is still room to negotiate, remedy or walk away.
1. Land registry: who, in fact, owns the property
The starting point is the permanent land-registry certificate. Definitive registration constitutes a presumption that the right exists and belongs to the registered holder, on the precise terms in which the registry defines it (Article 7 of the Land Registry Code). The priority principle also applies: the right registered first prevails (Article 6). Confirming the chain of title and the match between the seller and the person recorded in the registry is the first safety filter.
2. Charges and encumbrances: what runs with the property
Mortgages, attachments, seizures and other encumbrances run with the property, not the seller. A certificate revealing uncancelled charges requires, before the deed, their formal discharge or the allocation of part of the price to their cancellation. Buying without confirming this means, in practice, taking on someone else’s debt.
3. Use permit and planning compliance
The property’s actual use must correspond to what was licensed. The absence of a use permit, or a discrepancy between what was licensed and what was built, gives rise to contingencies that may frustrate financing, letting or resale. This point takes on new significance under the new Legal Framework for Urbanisation and Building (Decree-Law No. 108/2026 of 29 May, in force from 3 August 2026), which makes it mandatory to declare, in transactions involving property, whether a planning title exists. Planning verification ceases to be mere prudence and becomes a requirement of the transaction itself.
4. Areas, descriptions and horizontal property
The tax register, the land registry and reality do not always coincide. Discrepancies in area, outdated descriptions or defective horizontal-property titles affect the value and security of the asset. For an autonomous unit, it is important to confirm the conformity of the constitutive title and the correct identification of the unit.
5. Rights of first refusal
Certain third parties may have a right of first refusal on the acquisition and, if bypassed, may call the transaction into question: the residential tenant (Article 1091 of the Civil Code), co-owners (Article 1409) and, in certain circumstances, public entities. Identifying them in advance avoids the subsequent invalidation of the purchase.
6. Tax framework
IMT, IMI, AIMI, VAT and capital-gains tax vary according to the structure and object of the transaction. Tax analysis should form part of the due diligence from the outset, in coordination with the accountant or tax adviser, so that the tax bill does not come as a surprise once the contract is signed.
Before signing, confirm
The cost of a preventive review is negligible against the value of the property — and minimal against the cost of buying a problem. If you are considering acquiring or investing, rigorous due diligence protects both your assets and your decision.
Need a preventive review before you buy? Paulo Silva Silva, Advogado, dedicates his practice to Real Estate and Urban Planning Law, advising clients in Lisbon and throughout the country. Book a meeting or contact paulosilvasilva.adv@gmail.com · 916 055 901.
Read also
The use permit · Right of first refusal · Real estate lawyer in Lisbon
The information in this article is general and institutional in nature; it does not constitute legal advice and does not create a client relationship. Always confirm the version in force of the statutes cited in the Diário da República (dre.pt).