The limited lifespan of Luxembourg’s reinforced concrete apartments

For any property owner, the situation is an absolute nightmare: you have bought an older, yet very expensive flat, perhaps taking out a bank loan with a term of over 30 years, only to be confronted with the realisation that, even before the loan has been paid off, the entire building is in a disastrous state.

And not only that: during the costly renovation, it’s discovered that the building’s structure is even worse than feared due to construction defects. You’re demoted from proud apartment owner to co-owner of a derelict, reinforced concrete property.

Post-World War II construction

A similar situation recently unfolded in Differdange with its town hall. The administrative building, constructed in 1964, was originally set to undergo extensive renovation and expansion.

However, at the end of 2025, after work had already got underway, evidence that significant shoddy workmanship had likely been employed during the original construction was uncovered.

Test drilling revealed that the ceiling slabs, intended to be solid, were actually thin ribbed ceilings only six centimeters thick. This was far below the 27 centimeters documented in the building plans. As a result, the Differdange authorities decided to demolish the entire building.

The 60-year-old town hall in Differdange is now to be completely demolished because the building structure is in significantly worse condition than previously thought. © Photo credit: Marc Wilwert

“In principle, with buildings from the 1950s and 1960s, you always have to ask yourself whether the effort is worthwhile,” said Christoph Odenbreit, civil engineering professor at the University of Luxembourg. “In the years after the Second World War, things often had to be built quickly,” he explained. That is why many buildings were constructed rather “sparingly”, meaning that, from a structural point of view, they often no longer meet modern standards.

A small crack with fatal consequences

Furthermore, a comprehensive renovation often changes the requirements for the building. “Then the layout and architecture may no longer be suitable, nor does the façade, and the entire building services infrastructure is out of date too,” said Odenbreit. “And then it’s often cheaper to tear everything down and build anew.” And this is despite the fact that the structure may still be sound.

Christoph Odenbreit is conducting research at the University of Luxembourg into the reusability of building components.  © Photo credit: Eva Krins

Regarding the building’s structure, larger office or residential buildings exhibit various forms of steel and concrete combinations. In a composite concrete-steel structure, for example, the building consists of steel beams combined with concrete slabs.

Reinforced concrete, on the other hand, means that the concrete contains reinforcing steel. This provides additional stability and load-bearing capacity to the concrete – but only as long as the steel remains protected from external influences.

In principle, with buildings from the 1950s and 1960s, one must always ask whether the effort is worth it.

Christoph Odenbreit

Professor of civil engineering at the University of Luxembourg

“One of many construction errors from the 1960s: you have the façade elements and the reinforcement behind them,” explained the university professor. “And then all it takes is a small crack, water gets in, freezes, and a bit of concrete flakes off.”

And as soon as water also reaches the reinforcing steel and it rusts, more and more concrete crumbles away. “These are façade errors from that era; we’ve come a long way since then,” said Odenbreit.

Salt and water: a dangerous combination

Yet there is still a great deal of older stock, and some of it cannot simply be demolished anyway – even if one wanted to. Take, for example, the University of Saarbrücken’s canteen in neighbouring Saarland. The reinforced concrete building, erected in the late 1960s, is in urgent need of renovation because, amongst other things, the façade is damaged.

And another sticking point: the technical systems, which would also need to be replaced, are largely encased in the concrete. “If the whole concept no longer works, then demolition is quickly on the cards,” said the expert from the University of Luxembourg. Only, that is not possible in this case. The canteen is listed as a historic monument, regarded as a work of art and one of the most significant buildings in the Saarland.

Concrete is actually a building material that lasts forever.

Romain Weydert

Civil engineer and expert

The problem is usually not the building material itself, but rather the conditions. “You can easily build a house with reinforced concrete that lasts 100 years or more,” said Romain Weydert, a civil engineer and expert with an office in Luxembourg City. “Concrete is actually a building material that lasts forever,” he explained. Problems only arise when the reinforcement begins to rust. This can be accelerated by the interplay of two factors.

If the building components are exposed to moisture and salt, this damages the concrete and the reinforcing steel.  © Photo credit: Shutterstock

“In parking garages or buildings with underground parking, it’s often the combination of moisture and salt,” the expert explained. “Then the buildings rot from the base up, for example, if one of the columns is standing in a puddle.” But even in such cases, renovation is technically feasible. “When apartment complexes from the early 1970s are demolished, it’s usually not because the reinforced concrete has reached the end of its lifespan, but because it’s a matter of cost-benefit analysis,” said Weydert.

CO₂ savings are becoming increasingly important

According to Odenbreit, however, this calculation could change in favour of preserving such buildings in the future. He himself researches the reusability of building components. As chair of the ArcelorMittal Chair of Steel Construction at the university, he is working with several partners in industry and research on a modular system for recyclable building components.

“Previously, the primary focus was on saving materials; now the emphasis is more on saving labour, and in the future, CO₂ savings will also play an increasingly important role,” he explained.

To improve their carbon footprint, there are already cases where only the upper floors are demolished to make way for new construction, while the basements remain. Regarding the lifespan of such buildings, even preserving the existing structure can extend it by at least another 50 years. “If the renovation goes smoothly, a building can easily last the same amount of time again,” said Odenbreit.

(This article was originally published by Télécran and republished by the Luxemburger Wort. Machine translated using AI, with editing and adaptation by John Monaghan)