Building onto a shared party wall in Portugal

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Either owner of a shared wall may build on it and insert beams up to the middle of the wall (Código Civil, art. 1373.º), and may raise it at their own cost (art. 1374.º), but opening windows needs the other owner's consent (art. 1372.º).

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Law

Código Civil (Decreto-Lei n.º 47344/66)

Articles

1372.º to 1374.º

Building on the wall

Either owner may build on the wall and insert beams, up to the middle of the wall (art. 1373.º, n.º 1)

Thin walls

If the wall is thinner than 50 cm (five decimetres), the middle-of-the-wall limit does not apply (art. 1373.º, n.º 2)

Raising the wall

An owner may raise it at their own cost and then maintains the raised part (art. 1374.º, n.º 1)

Weak wall

If the wall cannot carry the extra height, the owner must rebuild all of it at their own cost, taking any extra thickness from their own side (art. 1374.º, n.º 2)

Windows and changes

Windows, small openings or other changes in a shared wall need the other owner's consent (art. 1372.º)

Official text

pgdlisboa.pt/leis/lei_mostra_articulado.php?nid=775&tabel...

Sources

pgdlisboa.pt/leis/lei_mostra_articulado.php?nid=775&tabel...
pgdlisboa.pt/leis/lei_mostra_articulado.php?nid=775&tabel...
pgdlisboa.pt/leis/lei_mostra_articulado.php?nid=775&tabel...

Checked

2026-11-05