Key facts
| Data | Value | Source |
|---|---|---|
| Usual order of the signs (1992) | Rust, cracks, spalling | Informes de la Construcción (CSIC), 1992 — Inspection, diagnosis and repair of high-alumina cement joists (in Spanish) |
| Air with no corrosion expected | Average relative humidity below 60% | Informes de la Construcción (CSIC, Spanish National Research Council), 1992 — Corrosion of reinforcement in high-alumina cement concrete and its inspection (in Spanish) |
| Areas with most damage in 1992 | Barcelona, Canary Islands and Seville | Informes de la Construcción (CSIC), 1992 — High-alumina cement concrete in Madrid (Madrid City Council, in Spanish) |
| Turó de la Peira collapse (Barcelona) | November 1990 | CAATEEB (Barcelona association of building surveyors) — “Aluminosi 20 anys”, L'Informatiu, 2010 (in Catalan) |
| Signs unique to high-alumina cement | None: damp Portland joists rust too | CAATEEB (Barcelona association of building surveyors) — “Aluminosi 20 anys”, L'Informatiu, 2010 (in Catalan) |
The signs, from mild to serious
First come rust stains on the underside of the joists, then cracks running along them, and finally concrete breaking away and exposed steel. That is how INTEMAC engineers described it in 1992 in Informes de la Construcción (CSIC). A ceiling that bulges or sags needs action the same day: warn the owners and call a professional.
In a hospital building with high-alumina cement joists, studied in 1992, INTEMAC engineers found damage ranging from rust stains on the underside of the joists to cracking and loss of the concrete cover over the steel, with prestressing wires that had lost much of their section and some that had snapped. That is the typical order: rust first, then cracks along the piece and finally spalling and exposed steel.
Another sign is a change of colour in the joist concrete, recorded in 1992 in the stands of a Madrid stadium. The extreme is a ceiling collapse, like the one at Turó de la Peira in Barcelona in November 1990: a ceiling that bulges or sags calls for action the same day.
Where to look on a viewing
Corrosion advances where there is water, so start with bathroom and kitchen ceilings, utility areas, top-floor flats under a roof or terrace and the areas next to drainpipes. In basements, garages and storerooms the joists are often visible without any finish.
Be wary of new suspended ceilings in those areas: they can hide the floor structure. In the Madrid stadium, suspended ceilings created damp cavities with condensation, and that is where the corrosion was worst. If you can, ask why they were installed.
Why is damp the key?
Because the steel in the joists corrodes mainly when the concrete is damp. According to CSIC researcher Carmen Andrade, in a 1992 study, if the air is always dry, with average relative humidity below 60%, no corrosion is to be expected even when the high-alumina cement concrete is partly converted.
Over the years, high-alumina concrete becomes more porous and, as it carbonates, loses the alkalinity that protects the steel. According to CSIC researcher Carmen Andrade, the rate of corrosion depends above all on how damp the concrete is; if the setting is always dry, with average relative humidity below 60%, corrosion is not to be expected even if the concrete is partly converted.
That is why Madrid City Council saw less damage in 1992 than on the Mediterranean coast, with its drier climate. And it is why a leak in a bathroom can matter more than the type of cement.
Are these signs unique to aluminosis?
No. The Barcelona association of building surveyors (CAATEEB) noted in a 2010 article that the typical damage in these floors does not depend on the cement: an ordinary Portland cement joist that stays damp for years also rusts and cracks. Seeing rust does not prove high-alumina cement, and not seeing it does not rule it out.
The Barcelona association of building surveyors points out that the typical damage in these floors does not depend on the cement: a Portland-cement joist that stays damp for years also rusts and cracks. Seeing rust does not prove there is high-alumina cement, and not seeing it does not rule it out.
A crack in the plaster or a damp patch can have other causes, such as a leak. Shape and position are what set them apart: those that follow the line of a joist deserve more attention.
What to do if you see a sign
Take dated photos with something for scale, note where they are and ask the owner and the property manager whether they know about them and whether there are reports or repairs. Ask for the building inspection (ITE or IEE) and look at the section on floors.
If you see fallen concrete, exposed steel or a sagging ceiling, do not wait: tell the owners' association and a professional, and keep people away from that area.
How HOUSINGFAX checks it
Check 03, “Is there a risk of aluminosis?”, combines the Catastro year with the damage recorded in the building inspection, where the regional register is integrated: cracks, deflection, corrosion of reinforcement, spalling or loss of section in floors, joists, beams or columns. The result is a level in words, from very low to very high, with what to check on the viewing.
The free report shows the check with your building's real data and the key information blurred; the essential report costs €11 and the complete report €19. The report does not replace a technical inspection of the building.
Short answers
What are the symptoms of aluminosis?
Rust stains on the underside of the joists, cracks running along them, concrete falling away, exposed steel and, in serious cases, sagging ceilings. They usually appear where there is damp.
Does a rust stain on the ceiling mean aluminosis?
Not on its own. It shows the steel is rusting, which also happens to Portland-cement joists exposed to damp. It is a reason for a professional to check the floor.
Can there be aluminosis without symptoms?
Yes. The joists may be high-alumina cement and still sound if the setting is dry. They may also be hidden behind a suspended ceiling. The absence of visible signs rules nothing out.
Which parts of a flat should I look at?
Bathroom and kitchen ceilings, utility areas, spots next to drainpipes, top-floor flats under a roof or terrace, and basements or garages, where the joists are often visible without any finish.
When is it urgent?
When concrete has fallen, steel is exposed or a ceiling bulges or sags. In that case, tell the owners' association and a professional, and keep people away from the area.
Official sources you can consult
The links let you review the primary source. Their inclusion does not widen their purpose or turn a piece of context into a diagnosis.
- Informes de la Construcción (CSIC, Spanish National Research Council), 1992 — Corrosion of reinforcement in high-alumina cement concrete and its inspection (in Spanish)
- Informes de la Construcción (CSIC), 1992 — Inspection, diagnosis and repair of high-alumina cement joists (in Spanish)
- Informes de la Construcción (CSIC), 1992 — High-alumina cement concrete in Madrid (Madrid City Council, in Spanish)
- CAATEEB (Barcelona association of building surveyors) — “Aluminosi 20 anys”, L'Informatiu, 2010 (in Catalan)