{"id":5185,"date":"2026-04-02T09:25:00","date_gmt":"2026-04-02T09:25:00","guid":{"rendered":"https:\/\/tiagorcorreia.com\/tmp-en-4682\/"},"modified":"2026-04-02T09:25:00","modified_gmt":"2026-04-02T09:25:00","slug":"seismic-vulnerability-assessment","status":"publish","type":"post","link":"https:\/\/tiagorcorreia.com\/en\/seismic-vulnerability-assessment\/","title":{"rendered":"Seismic vulnerability assessment: when it is mandatory and what it involves"},"content":{"rendered":"
Technical<\/strong><\/span>3 min read<\/span>Updated June 2026<\/span><\/div>\n

In a seismic country, rehabilitating without assessing the structure is a risk the law now regulates: since 2019, many rehabilitation works require a seismic vulnerability assessment report \u2014 and, when the result is insufficient, a strengthening design. Here is when it is mandatory, what it involves and why it matters even when it is not.<\/p>\n

1. When it is mandatory<\/h2>\n
\nREHABILITATION WORKSextension \u00b7 alteration \u00b7 reconstruction<\/p>\n

TRIGGERS (one is enough)
\n\u00b7 evident signs of structural degradation
\n\u00b7 change to the structural behaviour
\n\u00b7 intervention area > 25% of the gross area
\n\u00b7 cost > 25% of an equivalent new build
\n\u00b7 class III and IV buildings (schools, hospitals)<\/p>\n

ASSESSMENT REPORTsubmitted with the design<\/p>\n

SEISMIC STRENGTHENINGif safety is insufficient\n<\/p><\/div>\n

\n

The assessment is mandatory, among other cases, when the intervention area exceeds 25% of the building\u2019s gross area or the cost of the works exceeds 25% of the cost of an equivalent new construction \u2014 and strengthening is required when safety falls below 90% of what is demanded.<\/p>\n

Source: Portaria n.\u00ba 302\/2019 (DL 95\/2019 regime) \u2014 Di\u00e1rio da Rep\u00fablica<\/a><\/cite><\/p><\/blockquote>\n

2. What the study involves<\/h2>\n

Characterisation<\/strong> \u2014 survey of the existing structure, materials and pathologies; in old buildings this is serious diagnostic work, not desk work. Assessment<\/strong> \u2014 verification of the load-bearing capacity against the regulatory seismic action (Eurocode 8). Conclusions<\/strong> \u2014 either safety is sufficient, or the strengthening design becomes part of the operation. The report enters the application together with the architectural design \u2014 too late means redesigning.<\/p>\n

3. Why it matters even when it is not mandatory<\/h2>\n

In Lisbon and much of the country, the older building stock \u2014 masonry, \u00abplaca\u00bb, \u00abgaioleiro\u00bb \u2014 has well-known vulnerabilities. Assessing before buying or investing is a risk-management measure: the cost of the study is a fraction of the strengthening, and strengthening planned at design stage costs a fraction of improvised solutions on site. With the new technical framework of 2026<\/a>, the designer\u2019s responsibility for these choices has only increased.<\/p>\n

\n

\u201cIn an old building, the question is not whether the earthquake will come \u2014 it is whether the structure you are about to buy has already answered that question.\u201d<\/h2>\n

Tiago R. Correia<\/h3>\n

Architect<\/p><\/blockquote>\n

Frequently asked questions<\/span><\/p>\n

Does it apply to houses?<\/h3>\n

It applies to extension, alteration or reconstruction works that hit the triggers \u2014 regardless of use. Small interior refurbishments are, as a rule, out of scope.<\/p>\n

Who prepares the report?<\/h3>\n

Structural engineering, in coordination with the architecture \u2014 in our case, integrated from the preliminary study so that the strengthening solutions serve the design rather than fight it.<\/p>\n

How much does it cost?<\/h3>\n

It depends on the size and on access to the structure; it is typically a small fraction of the value of the works \u2014 and one of the most meaningful investments in safety that budget can carry.<\/p>\n<\/div>\n

Rehabilitating an old building?<\/span><\/p>\n

We integrate the seismic assessment into the design from day one \u2014 diagnosis, solutions and permitting without surprises.<\/p>\n

Talk to the studio<\/a><\/div>\n","protected":false},"excerpt":{"rendered":"

Technical3 min readUpdated June 2026 In a seismic country, rehabilitating without assessing the structure is a risk the law now regulates: since 2019, many rehabilitation works require a seismic vulnerability assessment report \u2014 and, when the result is insufficient, a strengthening design. Here is when it is mandatory, what it involves and why it matters […]<\/p>\n","protected":false},"author":1,"featured_media":4917,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[124],"tags":[],"class_list":["post-5185","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-technical-bim"],"_links":{"self":[{"href":"https:\/\/tiagorcorreia.com\/en\/wp-json\/wp\/v2\/posts\/5185","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/tiagorcorreia.com\/en\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/tiagorcorreia.com\/en\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/tiagorcorreia.com\/en\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/tiagorcorreia.com\/en\/wp-json\/wp\/v2\/comments?post=5185"}],"version-history":[{"count":0,"href":"https:\/\/tiagorcorreia.com\/en\/wp-json\/wp\/v2\/posts\/5185\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/tiagorcorreia.com\/en\/wp-json\/wp\/v2\/media\/4917"}],"wp:attachment":[{"href":"https:\/\/tiagorcorreia.com\/en\/wp-json\/wp\/v2\/media?parent=5185"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/tiagorcorreia.com\/en\/wp-json\/wp\/v2\/categories?post=5185"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/tiagorcorreia.com\/en\/wp-json\/wp\/v2\/tags?post=5185"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}