Failure patterns by construction era
What each era was built from, and what it fails at
The era narrows where an engineer looks first. It does not diagnose an individual building, and two properties of the same year diverge across a century of maintenance.
Pombalino and pre-1890
1755 onward
Built from
Masonry with a braced timber cage: gaiola, frontais and tabiques working in three dimensions.
Characteristic failure
The cage dismantled by open-plan renovation. Timber decay at joist and frame bearings inside the wall.
Visible at a viewing
Floors that bounce or announce every step. Internal walls removed in a recent refit. Cement render sealing a traditional wall.
Gaioleiro
1890 to 1930
Built from
Tall unreinforced masonry, weak lime mortars, timber floors, no coherent lateral system.
Characteristic failure
Joist ends decayed where they bear into wet masonry. Corroding embedded ironwork in balconies and cornices.
Visible at a viewing
New laminate laid over an old deck. Spalling render on projecting elements. Crack patterns running from opening corners.
The placa transition
1940 to 1970
Built from
Reinforced concrete floor slabs meeting masonry external walls. Galvanised steel plumbing, early wiring, asbestos-cement components.
Characteristic failure
Carbonation reaching thin and inconsistent cover. Galvanised pipe corroding from the inside. Wiring without earthing.
Visible at a viewing
Rust staining and spalling at concrete edges. Discoloured water and weak flow. Plasterboard covering services in one step.
Rapid expansion
1970 to 1990
Built from
Reinforced concrete frame with hollow ceramic brick infill. Single glazing, uninsulated cavities, continuous concrete elements.
Characteristic failure
Sits before the 1983 code became routine practice. Out-of-plane infill behaviour. Cold internal surfaces in winter.
Visible at a viewing
Mould in external wall corners and behind furniture. Ponding on flat terraces after rain. Earthing on some circuits and not others.
Modern appearance
1990 to 2005
Built from
Reinforced concrete frame, external insulation systems (capoto or ETICS), modern glazing.
Characteristic failure
Detailing at junctions. Insulation stopping short at slabs and columns. Water behind ETICS with no route out.
Visible at a viewing
Mould in a straight line along a ceiling edge or column position. Cracking along panel joints. Staining below window openings.
Read this before using the right-hand column
These signs identify the era and identify later work. They do not establish that any work was unauthorised, and they do not diagnose a defect. Both of those questions are answered against the approved drawings and by measurement on site.