Typical roof garden sections

Below 2 typical roof garden sections. These are only to give an idea. Of course the designs change depending on the needs in the project.

The upper with conventional design. For drainage 2 nonwoven geotextile (filter fabric) layer and gravel in between were used on top of the waterproofing layer. (mineral drainage layer) Heavy and cost more to take the gravel to the roof. Bigger load on the concrete.

The below is with a geocomposite drainage layer, lightweight and easy to use. The drainage layer is only between 0.5- 1 kg depending on the material. ıt is factory made and tested material. The access water from the vegetation and soil comes to drainage layer and carried to channels.

Roof Gardens and Green roofs

Two systems - Two purposes

Roof gardens:

• To be used as a garden
• with rich vegetation on a thick layer of soil
• requires maintenance
  

Green Roofs:

• environment-friendly roof with a thin vegetal cover
• not to be used as garden
• low maintenance vegetation (mosses,
  sedums, herbs) on a thin layer of
  lightweight substrate

Geosynthetics erosion mats-Fields of applications

Fields of application of erosion control geosynthetic mats

• erosion prevention for embankments and slopes
• protection of riverbanks against erosion
• support of vegetation on steep slopes and geomembranes

Roof garden tips

Now it is spring and you may want to prepare a green roof. You know roof garden does not mean a garden on the roof only. It may be top of an underground garage or top of a underground structure.

An important thing is not to forget the drainage core of the drainage sheets or layers with a nonwoven (may be woven but non woven is cheaper) filter fabric.

The ready made drainage products already have filter on them. But you have to wrap filter on the drainage core. Otherwise the soil, gravel or etc may go inside the drainage layer and block the drainage or at least decrease the amount of water to be drained.

Drainage sheets are used to remove excess water.

On the drainage layers you may use a water retention layer depending on where you live.

For more information on green roof solutions check our roof garden section for all posts of this subject.

Synthetics in erosion kontrol

How does a three dimensional synthetic mat function?

A geosynthetic erosion control mat helps nature to establish a natural, vegetation cover, as it :

• acts as an artificial root-system


• holds soil particles and seeds


• reduces water and wind velocities


• creates a micro-climate and favours germination of seeds and growth


• reinforces the vegetation cover in the root-zone
  
  The protection improves in time with the establishment of vegetation; this may be the
  unique aspect of the synthetic erosion control system

Roof garden system

In the design of roof gardens designers should choose the design system depending on the local weather and plant conditions. Because the climate and the plants are different in al the world. Especially the drainage layer is important for the plants.

Below another roof garden design is shown.

On the concrete substrate there is a waterproofing membrane and a root barrier on it. But in some designs it is possible to lay a nonwoven geotextile to protect the waterproofing layer and a protection concrete could be casted. So, the root barrier may not be used depending on the type of plants.

For the drain layer a geocomposite drainage layer can be used. Because it is made of light materials. Otherwise you should use gravel for drainage and it will cause a load of about 150 kg/m2 on the building. So, it is much better to use a composite drainage layer.

The drainage layer should have a good filter layer to prevent clogging.

On the drainage layer landscaping architects may use a water retention layer.

You can use a prevegetated mat and soil as growth medium on the top.

This system may be used as a good drainage system.

How can we control erosion?

In nature it often takes thousands of years till erosion has stopped and a gradual building up of a natural, vegetal cover has taken place.
Mankind can make artificial protection with concrete, stone, wood, etc. or help nature to establish a natural cover.

Also it is possible to use prefabricated plastic erosion control products. Three-dimensional erosion control mattings, made of polyamide monofilaments welded together where they cross, with an open space of over 95%.

What is Erosion and why erosion control?

What is erosion?

Erosion is displacement of solids (soil, mud, rock and other particles) by the agents of ocean currents, wind, water, or ice by downward or down-slope movement in response to gravity or by living organisms (in the case of bioerosion). see http://www.wikipedia.org/

Why erosion control?

2 reasons

• during the erosion process soil particles are transported, resulting in the gradual deformation and destruction of slopes, banks, shores, rivers bottoms, etc.


• elsewhere, erosion causes undesirable sedimentation on agricultural land and roads, in rivers and drainage systems, etc.

Erosion control

Why erosion control

• during the erosion process soil particles are transported, resulting in the gradual deformation and destruction of slopes, banks, shores, rivers bottoms, etc.
• elsewhere, erosion causes undesirable sedimentation on agricultural land and roads, in rivers and drainage systems, etc.

How can we control erosion?

a)Existing slopes:

• prevent removal of the vegetation
• in case of new slopes protect the fertile surface layer by means of:
  -coarse, less erodible surface
  -flatter slopes / terraces
  -surface cover with concrete, stones, plastic sheets
  -temporary plastic sheets over surface in rain season
  -geosynthetic mats
  -biodegradable mats

b)In case of slopes of ditches/channels:

• revetment structure
• concrete blocks