The problems we find in Porto property, again and again

Porto’s housing stock is old, characterful and, on a 20-minute viewing, often gorgeous. Inspect enough of it and the same defects come up again and again — nearly always behind a recent coat of paint, and nearly always missing from the listing. Here are the big ones, what they actually look like on the day, and how to tell a cosmetic niggle from a five-figure problem.

Water, in all its disguises

Damp is the number one issue I find, full stop — and it wears a lot of costumes. Rising damp in granite walls with no damp-proof course. Groundwater pushing up through a slab in a house that sits below street level. A garden bed or high external paving bridging water straight over the threshold. A parapet or a roof junction sending water down inside a wall so it surfaces as “rising” damp a floor below. The single most useful thing I can tell you: if a wall or floor is wet when it hasn’t rained for weeks, the water is coming from below or being fed from somewhere — not from the air. Cosmetic covering without curing the source is the most expensive false economy in Porto property. (I’ve written a whole piece on where the water actually comes from, because it matters that much.)

Roofs — and the bill you share

Traditional timber roofs under clay tile last a long time when maintained, and not long at all when they’re not. The patterns I see constantly: heavy lichen and biological growth holding moisture against the tiles; ridge capping long past its life; and the dead giveaway of piecemeal repairs — a patch of newer red tiles sitting next to old moss-covered ones, which tells you the roof has been nursed along in bits and never assessed as a whole. In an apartment, the sting is that the roof is a shared element: you pay your fraction of any re-cover through the permilagem, whether the leak is over your flat or not. A pending roof is one of the most common six-figure surprises in a Porto building, and it’s exactly the thing a buyer should be reading the condominium minutes about before they sign.

Parapets, flashings and junctions

If roofs are where the water gets in, parapet walls and junctions are where it gets in unnoticed. I regularly find old mesh-and-render repairs on parapets that have reopened and quietly become the primary pathway for water into the apartment below — while everyone inside blames the window. Failed flashings, and metal roof edges that terminate beneath the stone capping and channel water down inside the wall, do the same job. These are the leaks nobody photographs because you can’t see them from the street — and they’re the ones that need a builder on the roof, not a guess from the sofa.

Hidden timber rot

Timber floor and roof structures are everywhere in the older stock. Where they’ve met moisture — under bathrooms, against external walls, below a leaking roof or beside a wet light well — the beam ends rot inside the wall, invisible until someone lifts a board. I probe and check the vulnerable spots; the listing never mentions it because the vendor genuinely often doesn’t know.

Tired electrics

Plenty of properties still run installations decades out of date — undersized supply, no earth to parts of the circuit, aged wiring. It’s a safety issue and a sequencing one: a rewire is disruptive and has to happen before finishes go in, which is exactly why you want to know about it before you plan a renovation, not halfway through one.

The small things that tell a big story

Some of the most useful findings are tiny. A flexible corrugated waste pipe under a sink — cheap, prone to blockage and slow failure, and a classic source of the leak that surfaces as a stain on someone else’s ceiling. An air-conditioning compressor boxed into an enclosure with no ventilation, slowly cooking itself and shortening its own life. A condensate pipe punched straight through the façade and left. Window shutters dragging on the floor and scoring deep grooves into the boards. None of these is a deal-breaker on its own — but together they tell you how the place was really looked after, which is worth more than any single line item.

Cracks — which ones actually matter

Every old building has cracks and most are noise: hairline crazing in render, plaster shrinkage, the building simply being old. The ones I take seriously behave differently — stepped cracking that follows the mortar joints, cracks wider at one end than the other, cracking that mirrors on both sides of a wall, or anything fresh appearing over a recent repair. Those mean movement, and movement means finding the cause — usually water in the ground, a removed wall, or a neighbour’s works — before pricing the cure. A crack repaired without a diagnosis is just a crack with a head start.

Cosmetic, maintenance, or serious?

Here’s the thing: almost none of this should stop you buying. Most properties have a mix of cosmetic items, normal maintenance and the occasional genuine risk, and most issues are fixable. The entire point of an independent survey is to sort them into those three piles, put a realistic cost on each, and tell you which is which — so the price you pay reflects the property you’re actually buying, not the one in the photographs. That’s what our pre-purchase survey does.

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