In our previous articles, we explained how co-ownership is terminated and settled, and how decisions are made when co-owners cannot agree. This time we focus on a practical issue that often causes serious disputes:

what happens when one co-owner invests in the property more than their share, or invests without the required consent of the others?

The Civil Code does not provide a simple “step-by-step manual” for these situations. In practice, courts rely heavily on case law. Many principles were developed under the previous Civil Code, but they are still commonly applied today.

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Key point: It is not always about how much you spent, but about which legal category the investment falls into. Each category has different consequences for maturity, amount, and limitation.

1) Voluntary improvement without the required consent

This is the situation where a co-owner (often a minority owner) carries out reconstruction or other improvements on their own initiative, without the consent of the required majority.

In such cases, courts generally conclude that:

  • the claim is usually due only when co-ownership is terminated and settled,
  • during ongoing co-ownership, immediate reimbursement is usually not enforceable.

How the amount is calculated

The key factor is usually not nominal invoice cost, but actual appreciation:

  • market value before the investment,
  • market value after the investment,
  • the difference between them.

This difference may be equal to, higher than, or lower than the actual costs (in practice, often lower).

In this category, limitation typically starts when settlement occurs, because that is when the claim becomes due.

2) Costs necessary to preserve the property (emergency situation)

The second category is different. It covers urgent interventions that cannot be postponed, for example:

  • a roof or structure in danger of failure,
  • leaks or technical faults creating risk of damage,
  • urgent defects requiring immediate action.

Here, courts generally recognize that the co-owner may claim proportional reimbursement of reasonably incurred costs:

  • the claim becomes due when the costs are incurred,
  • limitation starts running from that moment.

In this category, claims are usually based on nominal, provable, and necessary costs.

3) Investment approved by majority but paid by one co-owner

The third category applies when the required majority approved the investment, but one co-owner paid for it in full.

Typically:

  • that co-owner may claim proportional reimbursement according to shares,
  • the claim is due when costs are incurred,
  • limitation starts from payment.

An important exception is a prior agreement that one co-owner would bear the costs without reimbursement (for example, as a voluntary contribution).

Practical recommendation

In all three categories, evidence is decisive. To enforce your claim, you should be able to prove:

  • what was done,
  • why it was necessary and reasonable,
  • how much was actually spent,
  • when the costs were incurred,
  • whether it was an emergency, a majority-approved investment, or unilateral action.

For voluntary improvements without consent, expert valuation is often required.

Summary:

  • Improvements without consent are usually settled only when co-ownership is terminated and divided.
  • Emergency preservation costs can typically be claimed immediately after they are incurred.
  • Majority-approved investments paid by one co-owner create an immediate proportional reimbursement claim.

If you are dealing with co-ownership investments and are unsure which category your case falls into, early legal assessment is critical — proper legal classification directly affects whether and when the claim can be enforced.