# Roofs in Porto: heavy rain, old buildings and what the council exempts > Roofs in Porto, with sources: IPMA rain, INE building age, what the council exempts from prior control and the UNESCO historic centre. - Page: https://telhadoseguro.pt/en/roofs-porto - Language: English - Updated: 2026-11-02 ## The roofs of Porto After Lisbon, Porto is the oldest municipality on this list in buildings: 52.2% date from before 1961 and 90.3% were built by 2000. 5.4% need deep repair, against 4.6% nationally. INE measures the whole building, not only the roof. A FEUP master's dissertation (2008) says the roofs of the Historic Centre are typically pitched, with canudo tile as the typical covering of old buildings. It describes frequent defects: tile flaking, efflorescence and parasitic vegetation. The author recommends zinc gutters and flashings in rehabilitations. That is the author's recommendation, not a council rule. The Historic Centre of Porto, Luiz I Bridge and Serra do Pilar Monastery are a UNESCO World Heritage Site: 51 hectares of property and a 186-hectare buffer zone. We found no official description of Porto roofs, nor the PDM (master plan) on colour or material. ## Buildings (INE Census 2021) - 39303 buildings counted in Porto - 52.2% built before 1961; 90.3% built up to 2000 - 5.4% with deep repair needs (whole building, not only the roof) - Antes de 1919: 5222 (13.3%) - 1919-1945: 7629 (19.4%) - 1946-1960: 7672 (19.5%) - 1961-1980: 9758 (24.8%) - 1981-1990: 2719 (6.9%) - 1991-2000: 2487 (6.3%) - 2001-2005: 1238 (3.1%) - 2006-2010: 1294 (3.3%) - 2011-2015: 516 (1.3%) - 2016-2021: 768 (2.0%) Source: INE, Census 2021, indicator 0011482, updated 2022-11-12. CC BY. ## Rain, wind and sun At the IPMA station Porto / Pedras Rubras (1991-2020) average rainfall is 1,146.9 mm a year and the mean temperature is 15.3 °C. There are 105.4 days a year with 1 mm of rain or more, 38.8 with 10 mm or more and 6.9 with 30 mm or more. The wettest day was 20 October 2019, with 92.9 mm. Frost is slight: 1.4 days a year, mostly in January, and -2.4 °C on 13 January 2003. In Porto the roof's enemy is water more than cold or heat: gutters, flashings and slope decide. ## Houses and roofs - Buildings in the centre have pitched roofs, canudo tile in most old cases according to the FEUP dissertation. With 105 days of rain a year, blocked gutters and loose flashings are the commonest cause of leaks. - In the UNESCO area and buffer zone the council applies protection rules. The exemption from prior control for roofs that we describe below does not hold for listed buildings, protection zones and Imóveis de Valor Patrimonial in the PDM. ## Rules and permits According to the Porto council's citizen portal, rebuilding a roof without changing the type, shape and covering material, and replacing roofing material that contains asbestos, are works of minor relevance exempt from prior control. Opening Velux-type attic windows and skylights is exempt too, if the shape of the roof does not change. The exemption does not hold for listed buildings or buildings in the process of being listed, their protection zones, and buildings inventoried in the PDM as Imóveis de Valor Patrimonial. Even exempt works need notice of start to the council at least 5 working days ahead. If scaffolding or hoarding occupies public space, the request is made at least 30 working days ahead. https://portaldomunicipe.cm-porto.pt/pt/-/reconstru%C3%A7%C3%A3o-de-cobertura ## Support and the 2026 storms in Porto Porto applies a 15% cut in the IMI rate for own permanent homes, and a 5-year IMI exemption, not renewable, in rehabilitation areas, for buildings in at least "good" condition and owners aged 18 to 34. The request is yearly, by 30 September. It is not direct support for roof works. Porto is not on the official lists of municipalities in calamity for storm Kristin. Decree-Law 79-A/2026 extended support, case by case, to those who show special and abnormal damage outside the lists. We found no official data on damaged roofs in Porto. ## Sources - [IPMA, normal Porto / Pedras Rubras](https://www.ipma.pt/opencms/bin/file.data/climate-normal/cn_91-20_PORTO_PEDRAS_RUBRAS.pdf) - [Porto council, roof reconstruction](https://portaldomunicipe.cm-porto.pt/pt/-/reconstru%C3%A7%C3%A3o-de-cobertura) - [Porto council, notice of start of works](https://portaldomunicipe.cm-porto.pt/pt/-/comunica%C3%A7%C3%A3o-de-in%C3%ADcio-dos-trabalhos-2) - [FEUP, dissertation on the Historic Centre](https://repositorio-aberto.up.pt/handle/10216/58536) - [UNESCO, Historic Centre of Porto](https://whc.unesco.org/en/list/755) - [INE, Census 2021 (0011482)](https://www.ine.pt/ine/json_indicador/pindica.jsp?op=2&varcd=0011482&lang=EN) ## FAQ ### Can I replace a roof in Porto without a permit? According to the citizen portal, rebuilding a roof without changing the type, shape and covering material is exempt from prior control. You must tell the council the works are starting, 5 working days ahead. The exemption does not hold for listed buildings, protection zones or Imóveis de Valor Patrimonial in the PDM. ### Does Porto exempt replacing an asbestos roof? According to the citizen portal, replacing roofing material that contains asbestos is exempt from prior control, with the same heritage exceptions. Removing asbestos has its own safety rules: see our asbestos guide. ### How much does it rain in Porto? At the Pedras Rubras station (IPMA, 1991-2020), 1,146.9 mm a year, 105.4 days with 1 mm or more and 6.9 days with 30 mm or more. It is one of the highest averages on this list. ### Can I fit a Velux window in Porto? According to the council, opening Velux-type attic windows is exempt from prior control if the roof shape does not change, with the heritage exceptions. Give notice of start of works. ### Was Porto declared a calamity zone for Kristin? It is not on the official lists of municipalities in calamity. Decree-Law 79-A/2026 allows support where there is special and abnormal damage, case by case. We have no data on roof damage in Porto. --- Source: https://telhadoseguro.pt/en/roofs-porto. Independent information, not legal or tax advice.