Sustainable concrete repair

The level of repairs to concrete structures due to concrete damage is lamentably poor, European research shows. The repairs must by law be guaranteed for 10 years, but in practice often do not even last five years. Four interest groups in Belgium are now sounding the alarm and calling for sustainable concrete repairs. An interview with one of the initiators, Paul Steenmans of FEREB vzw, the association of specialists in repair, protection and strengthening of concrete.

Various forms of concrete damage.

The European study on concrete repairs shows that in 55% of the repairs carried out, damage reappears after only five years. "Basically, they are then back to square one and in need of repair again," said Steenmans. The reason for the poor quality of concrete repairs in Belgium has a number of causes, according to Steenmans. "First, there is often a lack of proper diagnosis. A correct diagnosis of the concrete damage is absolutely necessary to achieve a good repair. How 'sick' is a building or object and what technique and means should be used to 'cure' the concrete structure? This is why the VCB (the Flemish Confederation of Construction), the WTCB (the Scientific and Technical Center for the Construction Industry), the NAV (Netwerk Architecten Vlaanderen) and FEREB have created the VIS track Sustainable Concrete Repair. With the aim of increasing the professional knowledge and skills of Belgian companies (contractors and architects), active in the concrete repair sector, so that a sustainable and qualitative result is obtained."

Collapsing balconies

Another cause underlies the great peak in apartment construction in the 1970s. Steenmans: "At that time, concrete technology was not at the level it is today. Construction had to be fast and, above all, cheap. There was hardly any control. Now - some fifty years on - we are experiencing the problems of this: more and more concrete structures are showing damage. A huge market in Belgium, where we distinguish between two types of damage: aesthetic and structural. Especially structural damage, which is not always immediately visible, causes major problems. Damage to the reinforcement in the concrete has major consequences. We don't have to explain that in the Netherlands, with the collapsed balconies as recent examples."

New legislation

On January 1, 2019, a new law will take effect in Belgium that should ease the performance of concrete repairs to apartment buildings. A blessing, thinks Steenmans. "After all, when problems occur in apartment buildings, the costs must be borne by all residents. There are always a few who are financially unable to bear the costs. In the past, that put a brake on repairs. The new law makes that easier."

Project-based warranty insurance

FEREB, in collaboration with TÜV, has finalized a procedure for the renovation of apartment buildings that includes all aspects of sustainable concrete repair. "It is a complete package in which first a diagnosis is made on the basis of a preliminary examination and then the repair work is carried out with certified products and by certified contractors. After execution, a certificate is drawn up and the modalities are defined for an annual inspection and maintenance during the 10-year warranty period. Because insurers and banks are also involved in the procedure, the works can always go ahead and a high-quality end result is guaranteed," concludes Steenmans.    

Text | Roel van Gils   Image | FEREB