Unmarried partners have no undivided co-ownership, so they acquire the flat into co-ownership in shares in the proportions stated in the purchase agreement. Towards the bank, both of them are usually co-debtors jointly and severally, regardless of the share each has in the flat. Set the shares according to what each of you is putting into the flat, and agree in writing on repayment and on what happens if you separate. A co-debtor who is not registered as an owner is repaying a loan on someone else’s flat and has only monetary claims against the other, not a share in the flat.
A couple who live together but are not married are buying their first flat. The bank wants both of them as co-debtors, one is putting in a larger part of their own funds, the other will repay more. At the signing, the only thing usually addressed is getting the loan approved; who will be the owner, and in what proportion, is decided in a hurry. Yet it is precisely that choice which determines what belongs to whom if the relationship ends.
Ownership: in shares, in the proportion stated in the agreement
Undivided co-ownership can arise only between spouses (Section 136(2) of the Civil Code). Partners therefore buy into co-ownership in shares. A share expresses the extent to which a co-owner participates in the rights and duties relating to the flat, and unless otherwise agreed the shares are equal (Section 137). If one of you is putting in substantially more of your own money, state that in the purchase agreement by a different proportion of shares, not merely by an oral promise. If the flat is registered in one name only, the other partner has no ownership right to it, even if they have been repaying the loan. The settlement of their own funds put into the purchase will be governed above all by what the partners agreed, and the repayments by the rules on joint debt; without a written agreement on whether it was a loan, a gift or something else, a dispute is likely.
The debt: joint and several
A loan agreement usually binds both co-debtors towards the bank jointly and severally. What that means is described by the Civil Code:
Where legislation or a court decision provides, or the parties agree, or it follows from the nature of the performance, that several debtors are to discharge a debt to the same creditor jointly and severally, the creditor is entitled to demand performance from any of them. If one debtor discharges the debt, the obligation of the others ceases.
— Section 511(1) of Act No. 40/1964 Coll. (unofficial English translation)
As between yourselves, your shares in the debt are equal unless you have agreed otherwise, and whoever paid more may claim reimbursement from the other according to that other’s share (Section 511(2) and (3)). The proportion in which you own the flat and the proportion in which you bear the debt are in no way linked by the law. A written agreement between the partners aligning the two proportions and determining how their own funds and repayments are to be set off is therefore worthwhile.
What happens on a break-up
Co-ownership can be dissolved by a written agreement on dissolution and settlement (Section 141(1)), typically by one of you taking the flat and buying the other out. If you do not agree, the court will decide on an application, having regard to the size of the shares and to effective use, and may award the flat to one party against reasonable compensation (Section 142(1)). The bank’s security right does not thereby cease, because a settlement may not be to the detriment of persons entitled to rights encumbering the property (Section 142(3)); whether one of you takes over the loan depends on the bank’s consent. We discuss this in more detail in encumbrances in the settlement of co-ownership.
If one of you wanted to sell your share to a third party, the other has a pre-emption right (Section 140). It does not apply where the share is transferred to a close person of the seller, for example their parent or sibling (Section 116). For that situation too, it is worth determining in the written agreement between the partners how the shares are to be dealt with.
How to set it up
- name both of you as buyers in the purchase agreement, with shares reflecting the actual contributions,
- agree in writing who repays how much and how the repayments will be taken into account on a break-up,
- agree the procedure if one of you wants to take over the flat, including valuation and the period for paying the other out,
- check with the lender what it will permit if one co-debtor leaves.
We align the purchase agreement and the shares with the bank’s conditions as part of our buying a property with a mortgage service. If the relationship ends and the flat has to be divided, we can assist with an agreement or with court proceedings as part of our termination and settlement of co-ownership service.
This answer provides general information on the law as at 12 September 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.
