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Earthquakes and roofs in Portugal: chimneys, tiles, what to do and the law on works

What happens to the roof in an earthquake, the most fragile old buildings, what to do before, during and after according to Civil Protection, when works need a seismic report and what we could not confirm.

Topic
Rules
Reading
8 min
Reviewed
04/11/2026
Earthquakes and roofs in Portugal: chimneys, tiles, what to do and the law on works

In an earthquake, tiles, chimneys and parapets are among the first things to fall. This guide explains what happens to the roof, what to do beforehand and straight afterwards, and what the law asks for when you carry out works.

Updated on 4 November 2026. General information. It is not a structural assessment and does not guarantee the safety of any building: only a civil engineer can assess that, building by building.

The essentials

  • Nobody predicts earthquakes. The IPMA says short-term prediction does not yet exist. Prepare beforehand.
  • The top of the house is the weak point. The IPMA mentions falling chimneys, balconies and ceilings, and says most injuries come from things that fall.
  • During: drop, cover, hold on (“baixar, proteger, aguardar”). These are the three gestures of Civil Protection (ANEPC).
  • Afterwards: do not climb onto the roof. Leave if the house has serious damage and only go back when the authorities advise it. Emergencies: 112.
  • Some roof works require a seismic report (Portaria n.º 302/2019).

The risk in Portugal

The IPMA describes mainland Portugal as an area of intermediate seismicity. The brochure by the ANEPC and the Portuguese Insurers’ Association (2018) says Lisbon and the Algarve are among the regions most prone to earthquakes.

Structures are designed with Eurocode 8 (NP EN 1998-1:2010) and its National Annex. According to the LNEC study that prepared the annex, there are two scenarios: type 1, earthquakes with their epicentre mainly at sea, and type 2, mainly on land. Each municipality (concelho) was placed in a zone. The zone of your municipality is given by the engineer on the project.

What happens to a roof in an earthquake

A thesis from the Faculty of Engineering of Porto (FEUP, 2020) studied chimneys, parapets and railings at the top of old stone houses and says they can be very vulnerable. It lists what decides whether an old façade falls outwards: the connections between walls, the connections of the walls to the floors and to the roof, tie rods or ring beams, and the quality of the masonry. It notes that the roof can push the walls and that its weight generates forces during an earthquake.

The table brings together the sources and our own practical suggestions:

Element Why it is a concern What to do
Chimney Tall and narrow. The IPMA mentions chimneys collapsing and fires starting in them Assessment by an engineer; the flashing is covered in the guide on chimneys and flashing
Parapet Wall at the top of the façade, can fall onto the street Assessment by an engineer
Loose tiles Can fall with the shaking Replace them as normal maintenance
Roof-to-wall connection If weak, they do not work together Only an engineer designs the strengthening
Heavy roof on weak walls More mass at the top Do not change it without a structural assessment

Old buildings. The LNEC says “gaioleiro” buildings (from the mid-19th to the early 20th century) have high seismic vulnerability because of weak materials and poor building techniques. In its tests, strengthening the connections between walls and floors and fitting tie rods between opposite walls mainly helped to control walls collapsing outwards. Pombaline buildings were designed after 1755 to resist better, but a study by the IST and the LNEC says most now need strengthening, partly because of past works that harmed their seismic resistance.

A lighter roof is not enough. In our reading of the sources, weight is only one factor: the connections, the walls and the timber also matter. A lighter roof alone does not make a building safe, and changing the weight can change how the structure behaves. Before a sandwich panel roof, talk to an engineer.

Before: what you can do

  • Look from the ground, with binoculars: tiles out of place, a leaning or cracked chimney. Do not climb up (see work at height).
  • Ask a civil engineer for an assessment if the house is old, of masonry, has a tall chimney or a parapet over the street, or if past works removed walls.
  • Follow the ANEPC: fix bookcases and heavy furniture to the walls, put heavy objects low down, prepare an emergency kit and teach everyone how to turn off the water, gas and electricity.
  • Check your insurance. The ANEPC asks you to confirm whether the policy covers earthquakes; in 2018 the brochure estimated that only 15% of homes had that cover. In April 2026 the Government announced mandatory insurance for homes, but we did not find the law published. See the guide on home insurance.

During the earthquake

Drop down, protect your head and neck and wait until the ground stops shaking. Indoors, shelter by a beam or pillar, in a corner or under a sturdy table, away from windows. Do not rush to the stairs or use the lift. In the street, keep away from run-down buildings, walls, chimneys and balconies (ANEPC).

After the earthquake

From the ANEPC: expect aftershocks and, near the sea, a possible tsunami (go to high, open ground). Turn off the water and gas and switch off the electricity, and do not strike matches. Leave the house if there is serious damage or a risk of collapse. For serious injuries, gas leaks or fires, call 112.

What we add, as common sense and not as an official rule:

  1. Do not go onto the roof or into the loft if you see new cracks or hear creaking. Aftershocks loosen what stayed in place.
  2. Look from a distance: a twisted chimney, a ridge out of place, a cracked gable, tiles on the ground.
  3. Indoors, look for new cracks in walls and ceilings, especially diagonal ones or near corners, and doors that no longer close. Photograph everything (see the first 48 hours).
  4. Call a civil engineer if you see these signs. If there is a danger to the street or to neighbours, tell the town hall (Câmara): the RJUE lets it order safety works or the demolition of anything threatening to collapse, at the request of any interested party (article 89), and waive formalities when there is an imminent risk of collapse (article 90(8)).

The law when you work on the roof

Repairing the roof as it was is conservation work (see the roof works permit). Seismic rules come in for alteration, extension or reconstruction works, whatever the age of the building (Decreto-Lei n.º 95/2019).

Portaria n.º 302/2019, in force since 15 November 2019, requires a seismic vulnerability assessment report when there is:

  • clear evidence of deterioration of the structure;
  • a change in the structural behaviour of the building;
  • an area of works above 25% of the gross floor area;
  • a cost above 25% of that of an equivalent new building.

In schools, hospitals and other buildings of importance class III or IV, the limits drop to 15%. If the building does not meet 90% of the seismic action of NP EN 1998-3:2017, a seismic strengthening design is mandatory. According to the Câmara of Amarante, the report is prepared by a qualified civil engineering professional.

The decree-law revoked, for buildings, the Safety and Actions Regulation (RSA, of 1983) and the 1958 earthquake regulation. Despacho Normativo n.º 21/2019 brought the Eurocodes into structural design for buildings, with a three-year transition.

In our reading, replacing a heavy roof with a light one, or timber with concrete, may “change the structural behaviour”. Ask the engineer and the town hall, in writing, before signing a contract.

Aid

We found no national aid for seismic strengthening of private homes; the fund announced in 2026 is about insurance. In Lisbon, according to Lusa (June 2025), the ReSist programme was due to launch technical support for private buildings in 2026, which we did not confirm.

What we could not confirm

  • The seismic zone of each municipality: we read the LNEC study (2008), not the standard, which is sold by the IPQ.
  • The numbering of the seismic article of Decreto-Lei n.º 95/2019: the portaria refers to article 7, the consolidated version we read shows article 8. The Diário da República website did not respond on 4 November 2026.
  • Changes in 2026 to the decree-law and the portaria after the RJUE revision.
  • Whether replacing the roof counts as a structural change: we read no official interpretation.
  • ReSist’s technical support and the mandatory insurance law.
  • An official guide to securing chimneys and parapets. We also did not read the “Aprender a prevenir” campaign or the National Emergency Plan.

Sources (read on 4 November 2026)

Questions and answers

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