The library of Delft University of Technology, designed by Mecanoo Architects, was completed in 1998 and won the National Steel Award because of its special construction. Because the intensive green roof was not constructed correctly, a complete renovation became necessary the first 10 years.
The library has a 5,500 m2 sloping grass roof, one of the first grass roofs built at this scale. However, the multifunctional use of space for which this grass roof was designed turned out to be a cause of various leaks after a short time. The roofing had become damaged due to its use as a ski slope and camping site, but also due to the sliding of the grass roof and insufficient attention to proper detailing.
Because of an initially cheap, loose-fitting roof insulation system choice, it was impossible to trace the leakage points and repairs had to be limited to symptom control. In 2006, the TU decided that complete renovation was the only good solution. The FOAMGLAS® insulation is completely adhered to the building, and both the insulation and the roof covering are completely stuck to each other. In this way, leakage and diffusion of moisture in the system is completely prevented.
The new construction with the sustainable and environmentally sound FOAMGLAS® Compact Roof System was completed in 2009, after the expiration of the guarantee period for the original roof insulation system.