Choosing a damp company: questions, documents and red flags
Many companies offer a free visit and sell their own system: the diagnosis and the work come from the same source. That does not make the quote wrong, but it makes it worth having your own view before signing.
These guides are for anyone about to ask for quotes or already holding some. They show which documents to ask for (an alvará or certificado de empreiteiro, the contractor licence issued by IMPIC, plus insurance and a written guarantee), which questions separate a technician from a salesperson, and which red flags justify a second opinion, such as pressure to sign on the same day or one method for every type of damp.
The key idea: arrive at the visit knowing the likely cause. If the company proposes treating rising damp on a second floor, or measures nothing before giving a price, you have reason to ask more. Start with the 12 questions to ask, take the free diagnosis and, if you already have a quote, get a second opinion. humidade.pt does not rank or recommend companies in these guides.
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Full guide →Frequently asked questions
Ask for the guarantee in writing, with its duration, what it covers (damp returning, plaster, paint) and what it excludes. Check whether it is tied to measurements before and after the treatment, and who takes them. A long guarantee is worth little if its conditions let any failure be blamed on condensation or lack of maintenance. Read the exclusions as closely as the duration.
Building firms need an alvará or certificado de empreiteiro issued by IMPIC, the Portuguese construction regulator. Ask for the number and check it with IMPIC before signing. Ask about insurance too, and who will actually do the work: the company itself or subcontractors. If something goes wrong later, you can use the Livro de Reclamações (official complaints book), which also exists online.
The diagnosis is free. If you ask to be contacted, the request goes to at most two partner companies, which pay per qualified request. No company pays to appear higher in the results, and your diagnosis result is calculated from your answers, not from the partners. The details are on the page explaining how we make money.