Unsafe floor construction used in up to 150 buildings in Netherlands

A construction method used in a parking garage at Eindhoven Airport that collapsed earlier this year, was also used in between 100 and 150 other buildings spread throughout the Netherlands, Paul Rijpstra, chairman of the Netherlands Construction Association, said to RTL Nieuws. Each of these buildings will be carefully inspected in the coming months.

The affected buildings were identified in a first analysis, in which 600 buildings were examined based on drawings and construction calculations. The next phase is to individually inspect each building by drilling samples from the concrete floorboards, and looking for cracks and sagging. This will take two to four weeks per building. Most of the affected buildings are hospitals, schools and offices, completed from 1999 when the construction method was first used.

The involved construction method is called wide-slab construction, according to the broadcaster. It involves relatively thin concrete slabs produced in a factory, that then get a thick layer of concrete poured over it at the site. The concrete slabs are supposed to have a rough top, so that the poured concrete binds to it properly. The slabs used in the Eindhoven Airport parking garage were smooth, which meant that the poured over concrete did not bind well to it, causing the collapse.

The upcoming inspections will determine whether the concrete slabs used in the affected buildings had rough tops. After that, the inspectors will check whether it is possible to fix any found mistakes, or whether the building will have to be demolished.

Several buildings have already been closed due to possibly unsafe floor structures, including Erasmus University's Polak building in Rotterdam and Windesheim University's building X in Zwolle. On Friday the Leerpark Presikhaaf high school in Arnhem also announced that it is closing temporarily due to this floor problem. The school will be closed until at least Wednesday, De Gelderlander reports.

After the Dutch Safety Board concluded that the parking garage collapsed due to unsafe floor construction, the Ministry of Home Affairs ordered all municipalities in the Netherlands to find out which of their buildings were constructed with the same method.