Agriculture Reference
In-Depth Information
(substrate) depth may be 25-150 mm, while the surface may be either level or graded
with low topographic features. Extensive living roofs are vegetated with typically low
growing plants. In general extensive living roofs are not irrigated, except in climates with
long summer drought periods, during the establishment period, on very steep roof
slopes with exposed aspect, or where aesthetics demand perpetual “green.” Extensive
living roofs are sensitive to foot trafic, and therefore vegetated areas should be
protected from direct contact (except for maintenance). The aim is to create a resilient
system to manage stormwater runoff, with relatively low requirements for maintenance,
including fertilizer, irrigation or weeding.
An intensive living roof is deined as:
A multi-layered system (drainage, growing media and plants) designed individually or as
a composite, manufactured system. The substrate depth is usually >150 mm, either
levelled or with variable topographic features. Although they are vegetated, they may
also incorporate hard landscape features like paving and structures like pergolas.
Vegetation allows and includes the whole palette of plants from herbaceous plants, to
shrubs and trees. Regular irrigation is usually required for intensive living roofs to protect
the more expensive resource (e.g., trees) or enable adequate production (e.g., urban
agriculture). Intensive living roofs' main application rests in the creation of a full garden
or landscape lying above a built structure, and are synonymous with rooftop gardens.
In this topic, we focus on technical and architectural design of extensive living
roofs. As will be explicitly detailed in Chapter 3 , extensive living roofs can provide
adequate capacity to manage runoff from “everyday” rainfall events that pose a
signiicant threat to receiving water health. Conversely, the complexity of the
construction, increased structural burden, and the potentially higher maintenance
of an intensive living roof make a less convincing tool for stormwater mitigation.
1.4 funCtional Components
A living roof typically consists of multiple layers ( Figure 1.3 ) , each of which plays
an important role in the overall system function. The basic function of each layer
Plants
Growing medium
Geotextile
Drainage layer
Waterprooing
membrane integrated
root barrier
Insulation
Vapour barrier
Figure 1.3
Typical living roof
assembly
Roof slab/deck
 
 
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