Planning compliance and unauthorised works: the risk you cannot see
Of all the risks of an auction, this is the one you see least and the one that blocks the most.
A mortgage is cancelled by the decree. An occupant leaves sooner or later. A planning irregularity, on the other hand, stays put, and until you fix it, it prevents you from doing the two things you probably bought for: reselling and taking out a mortgage loan.
What it is, in practice
The property must match what was authorised by the municipality and what is shown in the land registry. When it does not, there is an irregularity.
The most common forms are mundane:
An enclosed veranda that is not on the drawings. An attic made habitable. An ancillary room — cellar, garage, laundry — turned into a living space. A moved wall that changes the number of rooms. A mezzanine. An extension.
None of these seems serious when you look at the flat. All of them are, on paper.
Why it blocks things
Two concrete consequences, and they are the ones that count.
Resale. A deed of sale requires two different declarations, and it is best not to confuse them because they have different effects.
Cadastral compliance: the floor plan on file must match the actual state. If it does not, you cannot make that declaration and the notary will not complete the sale. It is the hardest stop.
The details of the building permit: they must be cited in the deed, and leaving them out affects its validity. A discrepancy with the permit does not always block the sale by itself, but it remains a problem that passes to the buyer — and a buyer who is informed either pulls out or demands a discount.
In practice, in both cases the property is yours and you sell it badly, or not at all.
The mortgage. A bank is reluctant to lend on a non-compliant property, because if it has to enforce, it ends up with the same problem. This applies to you if you apply for a mortgage, and to whoever wants to buy from you.
Then there is the administrative side: depending on how serious it is, the municipality can order the property to be restored to its original state, that is, the demolition of whatever should not be there.
The difference between an irregularity and unauthorised work
It is not an academic distinction: it decides whether the problem costs a few thousand euros or cannot be fixed at all.
A cadastral irregularity — the floor plan on file does not match the actual state, but the work was authorised — is fixed with a cadastral update. It costs little, a technical professional does it, it is routine.
A planning irregularity that can be regularised — the work was not authorised but could have been — is regularised through a compliance assessment, paying charges and penalties. It costs more and takes time, but it gets closed.
Unauthorised work that cannot be regularised — the work could not be authorised then and cannot be now, typically because it breaches volume limits or distances, or stands in a protected area — cannot be regularised. A demolition order remains the only route.
Which of the three cases applies is decided by the municipality on the basis of the planning instruments, not by the expert or the seller.
Where to read it in the appraisal report
The appraisal report has a section on building and planning compliance. It is the one to read first when you are assessing a property you are seriously interested in.
Look for three things.
The details of the building permit: licence, concession, building permit, with number and date. If the expert writes that it was not possible to find them, that is a warning sign.
The comparison between the actual state and the floor plan. The expert almost always makes it and states it explicitly. Phrases such as “an irregularity is found” or “the state of the premises does not match” must be taken seriously, even when the tone of the document makes them seem marginal.
The assessment of whether it can be regularised and the estimated cost. Some experts make it and give a figure. When it is there, it is the most valuable information in the document — and it must still be checked with the municipality, because the expert does not issue permits.
If the appraisal report is silent on all this, it does not mean everything is in order: it means you do not know.
How much it costs to find out beforehand
Much less than finding out afterwards.
A request for access to the records at the municipality gives you the building permits on file. It costs a few tens of euros and takes a few weeks, so it should be requested as soon as a lot interests you, not just before the deadline.
A technical professional who compares the floor plan with the actual state during the viewing will tell you in half an hour whether there is a discrepancy. It is the single investment with the highest return in the whole due diligence of an auction.
Frequently asked questions
Does the transfer decree regularise unauthorised works? No. It cancels mortgages and attachments, not building irregularities: the property comes as it is.
Can I buy a property with irregularities? Yes, and it happens often. The point is to know beforehand, to know whether it can be regularised and at what cost, and to price it accordingly.
Who pays for the regularisation? The buyer.
Will the bank give me a mortgage on a non-compliant property? Normally not, or not until it has been regularised. If your plan involves a mortgage, compliance must be checked before bidding.
How do I find out whether it can be regularised? The municipality decides on the basis of the planning instruments in force. The appraisal report may indicate it, but the definitive answer comes from a technical professional after accessing the records.
Are irregularities common at auctions? Common enough that compliance should never be taken for granted. Properties that end up in enforcement proceedings have often been managed for years without keeping the paperwork up to date.
This guide describes the general framework and is not a substitute for the opinion of a technical professional. Whether work can be regularised depends on the municipality’s planning instruments: what emerges from the records and from the check with the municipal technical office always prevails.