The most common root barriers used are thin polyethylene sheets laid over the waterproofing membrane.
Green roof airation layer.
Of course this is not all that.
The clay and silt content of materials used in a rock aggregate drainage layer should be 10 per cent by mass.
They can also be used to increase the size of the root growth zone and provide space for an aeration system.
The rock aggregate should also have a suitable ph and be low in soluble salts to ensure plant growth is not adversely affected.
They fall into three main categories extensive intensive and semi intensive.
Protection drainage and filtration.
Older green roofs often used a permeable layer of rock aggregate such as scoria or gravel for drainage.
Root barrier the root barrier is the system that avoids the membrane underneath from being pierced and penetrated by roots ensuring that the system can remain in top shape for as long as it possibly can without needing any adjustments or changes.
These may not be required if the waterproof membrane is certified as root resistant.
Thicker welded root barriers will be needed for green roofs involving trees bamboo or other vigorous spreading grasses.
They can also provide additional functions for the green roof other than just drainage.
What is a green roof.
It is made of a filtration veil and the polyamide monofilament fibre network layer.
Although there are no precise definitions of them an extensive green roof has a shallow growing medium usually less than six inches with a modest roof load limited plant diversity minimal.
To assist in excess water drainage rubber or plastic modeled drainage elements are often included in this layer.
Additional green roof layers.
Also the green roof drainage layer material is made to be sturdy and strong so that piercing can be limited and that the integrity of the entire program can be retained with ease.
A green roof is a layer of vegetation planted over a waterproofing system that is installed on top of a flat or slightly sloped roof.