A roof that changes colour with the season

Flat roofs at TU Delft cover a total of more than 170,000 m2, 13,300 m2 of which are covered in sedum, grass, or a mix of the two.

Green roofs have numerous benefits. They provide good isolation; cooling in the summer and retaining heat in the winter. That helps to cut energy bills – by an estimated 5%, dependent on the type and thickness of cover. In addition to this economic benefit, a green roof also looks attractive. Sedum changes colour with the seasons. And a grassed roof or rooftop garden can be used for relaxation, recreation or studying in the open air, such as the grassed roof of the TU Delft Library. Of course, these social effects are more difficult to gauge than the energy savings.

Overview of buildings with natural roof covering

Building

New or existing building

m2

Since

Type of covering

TU Delft Library

Existing building

5,500

2009

Grass

Faculty of Technology, Policy and Management (building 31)

Existing building

1,400

700 m2 since 2002 and 700 m2 since 2016

Mix of sedum and different types of grass

Applied Sciences (building 22)

Existing building

600

2010

Sedum

Aerospace Engineering (building 61)

Existing building

2,000

2017

Mix of sedum and different types of grass

Civil Engineering (building 23)

Existing building

1,400

(2x700)

2018

‘Polder’ roof

3ME (building 34)

Existing building

1900

2018

Sedum and various types of grass

Applied Sciences South (building 58)

New construction work

500

2016

Various grasses and trees (in pots)

Total

 

13,300