After accepting an estate, siblings in co-ownership often want to sell and split cash. One refusal — attachment, belief the price is low, or using the home — stops everything. In Madrid this is routine: the law does not require being “reasonable”; it requires respecting shares and majorities. This analysis explains why one heir can block, what the others can do and when court is the least bad option.
Why one heir can stop a sale
In undivided co-ownership, disposing of the whole or major acts usually needs every co-owner. Your 70% share on paper does not let you sell the entire flat alone.
The dissenting heir is not always acting in bad faith. Sometimes they live there, wait for the market or feel pressured below value. Sometimes blocking forces allocation in their favour.
Selling “only my share” rarely fixes it: the buyer gets a co-ownership stake, not a usable home, and price collapses.
The exit is compensation talks, termination of co-ownership or ultimately judicial division. Skipping that order lengthens conflict for years.
Negotiation before court
Independent appraisal and a real offer change the conversation. “We sell at X; your net is Y” is harder to reject than “sign because I say so”.
Allocation to whoever keeps the property — paying compensation — may satisfy someone who blocked an external sale. Check they can finance and take the mortgage.
Agreed deadlines and penalties between capable adults can unblock if trust remains. We put it in writing; verbal inheritance deals feed future litigation.
If one heir has exclusive use, regulating rent or offset avoids blocking plus free occupancy.
Partition, termination and forced sale
When talks fail, civil route is division of common property. For practically indivisible homes that usually means court sale and split proceeds.
It is not instant: procedure, court valuation, auction or direct sale phases and costs. It still unblocks what unanimity prevents.
Mixing pending partition with a flat sale creates chaos. Know whether the estate is accepted and registered and all heirs identified.
We order the file: inventory, title, mortgage and one strategy. Suing without clear title wastes time and money.
Mistakes that worsen blocking
Unauthorized entry, lock changes or keeping rent without sharing can turn civil conflict into something worse.
Accepting off-book offers without consensus exposes the selling heir to liability to the others.
Renouncing “to avoid a fight” without calculating effects on others’ shares can be an accidental gift to the blocker.
Listing or showing the property without agreement looks harmless; legally it can harm the estate community.
What we need on the first call
Number of heirs, title (will or declaration of heirs) and whether the property is registered to all.
Who blocks, stated reason, exclusive use, mortgage or squatting.
Recent offers or appraisals and urgency (liquidity, tax deadlines, community charges).
With that we advise doorstep deal, termination or division claim. Goal: exit co-ownership, not win Sunday’s argument.