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Around 70% of Portugal's housing stock was built before 1990, before mechanical ventilation was standard practice (INE). Meanwhile, average relative humidity runs near 77% in Porto through winter, and regularly exceeds 70% across the Lisbon region.
The result: cold masonry walls, limited airflow, and condensation that has nowhere to go.
Mold isn't bad luck. It's the predictable outcome of older buildings meeting a humid climate, which is why diagnosing the actual cause matters more than guessing from how it looks.
Learn more about why mold is so common in Portugal →Three ways mold.pt helps people in Portugal deal with mold, moisture, humidity, and damp.
Independent moisture mapping, humidity readings, and lab-verified testing to confirm the actual cause, not a guess.
Book an Inspection →Get matched with a vetted contractor for remediation, damp-proofing, or ventilation work, based on your confirmed cause.
See How Remediation Works →Room-by-room habits, target humidity numbers, and the mistakes that make it worse, so it doesn't come back.
See What Reduces Risk →Traces the source, not just the symptom
Spots hidden damp before it's visible
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Mainland Portugal, remote assessment everywhere
mold.pt inspects properties across mainland Portugal. These are the nine areas we see the most, each with its own climate and building-stock context.
~77% average winter humidity (IPMA), rising damp risk in Ribeira and Miragaia granite construction.
View Porto coverage → Elevated RiskCondensation is the main risk here; older concrete-frame buildings conduct outdoor cold straight through uninsulated structural points.
View Cascais coverage → Moderate RiskRising damp in the historic centre, condensation in mid-century apartment blocks.
View Lisboa coverage → Higher RiskMinho region, mainland Portugal's highest-rainfall area, older stone and masonry housing.
View Braga coverage → Higher RiskRia de Aveiro lagoon keeps ambient humidity elevated across much of the city.
View Aveiro coverage → Moderate RiskSado estuary geography, condensation risk in older city-centre and riverside buildings.
View Setúbal coverage → Higher RiskAmong mainland Portugal's highest rainfall totals, granite riverside buildings near the Lima estuary.
View Viana do Castelo coverage → Higher RiskHigh-rainfall Minho climate, narrow historic streets slow how fast granite walls dry out.
View Guimarães coverage → Moderate RiskMondego riverside humidity, one of Portugal's oldest and densest historic housing stocks.
View Coimbra coverage →
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