Attic conversion: do you need a permit in Portugal?

Independent site: we are not a public authority, and this is not legal or tax advice.

Fitting out an attic as living space inside the existing roof is exempt interior work, but a change of use must be filed. Raising the roof, adding dormers or roof windows changes the outside and needs a licence.

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Answer

Inside fit-out exempt; change-of-use filing needed; exterior changes need a licence

Inside works

Exempt if nothing changes outside and stability is not affected (art 6(1)(b))

Exterior changes

Raising the roof or adding windows or dormers changes heights, roofs or facades (art 6(1)(b)(i)) and needs a licence, or prior communication where art 4(4) allows it

Change of use

Filed as comunicação prévia com prazo if no licensed works came first (art 4(5) and 62-B)

Council rules

Your council can add detail in its own building regulation where the law lets it, so ask before you start.

Legal basis

RJUE art 2(d) and (e), 4(5), 6(1)(b) and 62-B, RJUE (Decreto-Lei 555/99) as republished in the Annex of Decreto-Lei 108/2026

Sources

data.dre.pt/eli/dec-lei/108/2026/05/29/p/dre/pt/pdf

Checked

2026-11-05