I walk an old house in the same order every time, and that order ignores what the house shows you first. The buyer notices cracked plaster, brown tiling and a lean-to extension with a corrugated roof; those three can be costed in advance. While they are busy being annoyed by them, they walk past the dark band at the bottom of the wall, past a crack running diagonally up from a window corner, and past the fact that the extension is not in the land registry. Those items do not raise a budget, they rewrite it. So this piece is ordered by what a defect costs, not by how alarming it looks.
Why does the list of alarming defects not match the list of expensive ones?
An old building gives up its information unevenly: surfaces speak loudly and cheaply, while structure, moisture, the ground and the paperwork speak quietly and expensively. A settled corner or an unregistered extension are not in the plan, and nobody bounds them on a viewing.
| What bothers the buyer | How it looks | Real difficulty | Who judges it |
|---|---|---|---|
| Hairline cracks across plaster | alarming | low, a surface matter | architect |
| Dated interior and tiling | off-putting | low, a planned cost | architect |
| Diagonal crack from an opening | like a detail | high, possible settlement | structural engineer |
| Salt efflorescence at the wall base | like ordinary damp | high, reaches floors and services | damp specialist |
| Low clear height, timber beam ceilings | like the character of the house | high, constrains heating and ventilation | services engineer |
| Extension neither registered nor permitted | invisible | critical, legal and financial | lawyer and building authority |
Paperwork can be checked in two days, structure has to be seen in person, moisture and radon measured over time.
What should you verify before the first viewing?
The first document is a current land registry extract, not the one an agent sent a month ago. I want the owner and the share, any flag for a pending entry, and above all section C: liens, easements, rights of way, life tenancies. A neighbour's right of way across the yard transfers with the house and can kill the whole plan for a garage.
The second step is comparing the cadastral map with reality: what stands but is not drawn (an extension, a garage, sometimes a whole storey), and what is drawn where nothing stands any more. Then I ask for the original drawings, the permit, the occupancy decision and paperwork for every later change. If there is nothing for the extension, that is not a formality. Building act 25/2025 Z. z., which on 1 April 2025 replaced the construction act of 1976, changed the rules for unpermitted works, and the direction of that change is less tolerant of unauthorised building. I do not quote a procedure or a penalty here: they depend on the current wording and belong to a lawyer. Obligations attach to the owner of the structure, so what somebody built twenty years ago becomes yours on transfer. Either it is settled before transfer and on the seller's side, or it is reflected in the price.
The third area is restrictions the extract does not show. Protection zones for utilities, transport, water sources or forest come from separate legislation and from the operators' statements (covered in the piece on protection zones and easements). Heritage belongs here too: whether the house is a listed building or merely stands in a heritage zone changes what is approvable. The fourth area is the land-use plan: zoning information under act 200/2022 Z. z. tells you whether the intended use is permissible, how far you may add a storey, and whether the plot can be divided. Regulations are local.
How do you read a crack, and what does a lower corner mean?
On a crack I look at four things: direction, how the width varies, whether it runs only through plaster or through the masonry too, and whether it is live. A diagonal crack from the corner of a window, clearly wider at one end and continuing across more than one storey, is the classic picture of differential building settlement. The cause is usually changed bearing capacity or moisture in the subsoil, a leaking drain washing fines out from under the footing, or a later extension founded shallower beside the old part. Whether a crack is live cannot be told from one visit, only measured over time.
If the house has even one crack of that kind, or if one corner sits visibly lower, I want a structural assessment before signing. On the same visit the engineer says which walls are load-bearing and how much can actually be opened up. Removing a load-bearing wall is solvable, but its difficulty is set by the floor above it; a timber beam ceiling, a filler-block ceiling on steel joists and a monolithic slab are three different jobs. I always go into the roof space with a torch: rafter feet, water staining around the chimney, insect damage. New roof covering over a rotten truss is not rare.
Why is moisture the most expensive defect in an old house?
Damp at the base of the building is the most common genuinely serious defect in older Slovak houses, and the hardest one to bound with a budget. Houses from before the middle of the twentieth century often have no horizontal damp proofing at all, and where they do it is a bituminous layer at the end of its life. Water then travels up the masonry by capillary rise, carrying salts that crystallise in the plaster. The signs are readable: a dark or white-bloomed band at the base of the wall, fallen plaster, a cold smell in the end room, a plinth repaired recently and already moving again.
One unpleasant sentence belongs here: retrofit damp proofing is the most dishonestly sold work in Slovakia. Masonry injection is a legitimate method, but it only works after diagnosis, meaning the source of water, the moisture and salt profile of the wall, and the state of the original damp proofing. It does nothing about water from a broken drain, from ground raised above floor level, from missing rainwater drainage, or from a cement render that sealed moisture in. The order is: find the source, remove the water, then choose a method. Anyone who quotes a price for injection without measuring anything is selling a product, not a solution.
When should radon be dealt with, and in what order?
Slovakia has geology with locally elevated radon risk, and older houses carry two disadvantages at once: interrupted or entirely absent membrane under the ground-bearing floor, and a permeable, unventilated cellar from which air rises into the living space. The order is unambiguous: a radon survey first, a decision about remedy second. A brief spot reading says little; what counts is a long-term measurement in this house during the heating season. Reference levels in Bq/m3 are set by radiation protection legislation, and the figure is to be read from the current regulation and the measurement report, not from a blog.
A serious measurement usually cannot be completed before signing, so carry it as a conditional budget line rather than dropping it. Remedies range from ventilation and sealing penetrations, through sub-floor depressurisation, to a new floor with a radon barrier, which a deep renovation involves anyway.
Can the services be brought up to current standards?
The electrical installation is usually the clearest line item. Aluminium conductors, a missing protective conductor, no residual current device and two circuits for the whole house do not mean a patch, they mean rewiring the entire building, which means chases in every wall and new finishes: replace the electrics and you replace plaster and floors too. Galvanised steel pipework is in a similar position. On drainage I ask two things: whether the house is on a public sewer or a cesspool, and what condition the drain below the floor is in. A camera survey is cheap, and it often finds the source of damp. On the chimney it comes down to whether there is a usable flue for a modern appliance and whether it can be lined.
Then comes the question buyers almost never ask: is there a route? An underfloor heating build-up takes centimetres you cannot find in a house with low clear height and timber beam ceilings, and raising the floor runs into door heights and window sills. Ventilation with heat recovery needs a route for ducts, meaning dropped ceilings or a riser, cutting into the proportions that made you want the house.
What would a deep renovation of this house involve?
The energy certificate produced for the sale reports a class, not defects. A real estimate starts with the envelope: what the masonry is and how wet it is, whether the ceiling to an unheated attic is insulated, what the ground floor is, what the windows are, and where thermal bridges show without a thermal camera. Deep renovation is a set of measures in sequence rather than a single item, and that sequence is covered in the piece on the order of measures in a deep renovation. For a buyer one rule is enough: moisture is dealt with before insulation, because an insulated wall with a wet base is a worse condition than an uninsulated one.
Which materials from certain periods deserve to be taken seriously?
In houses from roughly the 1960s to the 1980s I assume asbestos cement products until proven otherwise: corrugated roofing and facade cladding, waste and flue pipes, some floor coverings and adhesives. That is not a reason not to buy, it is a reason to know in advance: firmly bound, undisturbed asbestos is a different problem from the same material cut with a grinder during demolition. Removal and disposal belong to an authorised contractor, they are a separate budget line, and they should not surface on the morning of the demolition. I treat old lead-based paints and coal tar layers in floors the same way: where there is doubt, sampling happens before the work.
What should you commission before signing, and what can wait?
Paying for surveys on a house you do not own yet feels wrong. The cost is small against the price of the house, and a single finding repays it several times over.
| Step | When | Why in this order |
|---|---|---|
| Registry extract and cadastral map against reality | before signing | available at once, exposes encumbrances |
| Zoning information from the municipality | before signing | decides whether the intent is permissible |
| Permit and occupancy documents including changes | before signing | the new owner inherits the problem |
| Viewing with an architect, and an engineer if needed | before signing | half a day decides the plan |
| Moisture diagnosis with actual measurement | before signing | costliest defect, non-destructive |
| Camera survey of the below-floor drain | before signing, if access allows | hidden source of water |
| Long-term radon measurement | after purchase | needs a season and a closed-up house |
| Openings into floors, ceilings and roof structure | after purchase | destructive, requires ownership |
| Asbestos and lead sampling | after purchase, before demolition | governs method and disposal |
| Energy audit and measured survey | after purchase | input to design and subsidy |
This walk-through does not answer whether to renovate the house or demolish it and build anew. It answers what you are actually buying, and it produces the inputs for that decision: the residual value of the structure, the extent of unavoidable work and how much uncertainty is left. How to reach the decision is covered in the piece on renovating versus demolishing and building anew. Sign first and ask what you bought afterwards, and you have narrowed your options to whatever the house allows.