TU Library, Delft

Pitched green roof with lawn and railing
project profile data
Area: ca. 5,500 m²
Reconstruction: 2009
Architect/Design: Mecanoo architecten, Delft
Contractor: Van der Tol B.V., Amsterdam and
Mastum Daksystemen B.V., De Meern
System build-up: “Lawn” with Elastodrain® EL 202 and a permanently installed irrigation system
Project report

The library of the University of Technology in Delft was designed as an extension of the surrounding landscape. Like a wedge the building seems to be pushed below the lawn area, which is often used by the students for sitting or sunbathing during summer time. Unfortunately, after little more than ten years of use, significant deficiencies appeared at the roof and it had to be subjected to an overall refurbishment. So a pressure-resistant thermal insulation made of foam glass was installed as well as a new bituminous waterproofing with a top layer of root resistant EPDM. Also, the green roof build build-up was chosen in such a way that it resists even the highest mechanical demands; therefore it is based on the solid drainage and protection layer Elastodrain® EL 202.

The roof area is now made fully usable again and even in case somebody tries “digging” or skiing or sleighing in winter time – against orders –, the 13° sloped roof will remain perfectly protected.

  • Pitched green roof with lawn
    A broad flight of steps leads up to the entrance under the green roof.
  • Green roof with lawn and railing
    Railings provide safe access to the green roof.
  • Large green roof with lawn
    The library is topped by a huge steel cone as a symbol of technical engineering.
  • Grass and clover
    Clover and grass form a resilient and low-maintenance green carpet.
  • Bird's eye view of the library building with the green roof
    The building seems to be pushed below the lawn like a wedge.
  • People sunbathing on a pitched grass roof
    The roof is often used for recreation - even during winter time.
  • Grass roof with railing and raven
    The green roof also provides habitats for birds.