Dead and imposed loads should be calculated in accordance with bs en 1991 1 1 be en 1991 1 3 and bs en 1991 1 4 and should include the weight of the waterproofing system saturated weight of the green roof components and substrate vegetation snow loads and imposed loads such as access by people and vehicles as well as point loads for.
Green roof roof drainage concepts.
For green roofs small plants with fibrous roots and low water requirements are best suited.
The green roof can be established on any load bearing components concrete tanbark wood.
Operating within the green roof are the interception of rainfall by the plant layer infiltration and storage in the substrate and reservoir storage in the drainage layer.
The waterproofing membrane root barrier the drainage layer.
In addition to stormwater source control green roofs.
These are collector drains that are designed to flow when only partly full.
Is not able to drain properly it can negatively impact the vegetation due to over.
The most critical role of the drainage layer is to provide an adequate flow of water off the roof during and after rainfall.
The roof garden build up allows for the realisation of a variety of design concepts even waterfeatures.
A green roof may require a separately plumbed secondary drainage system also known as the overflow relief system.
The drainage capacity is tested according to en iso 12598.
Primary drainage systems are not designed to remove all of the water that falls on a roof during exceptionally heavy rain.
The unique needs of a green roof installation.
The design of the different drainage layers allows for a portion of the stormwater to be retained above where the water is allowed to flow freely off of the roof.
Having proper drainage on a green roof is a critical aspect of the system.
On zero degree roofs a roof dam irrigation system can be installed which stores up to 40 mm of water.
The load bearing component of the roof.
Saturation of the soil.
The growing medium substrate the plant layer.
The roof can provide natural substrate and processes for plant growth.
A water proof layer material for water retention and proper drainage helps plant growth and at the same time protects the roof and building from damage.
As the soil takes on excessive amounts of water it continues to.
It is suitable for lawns perennials and with deeper growing media for shrubs and trees.
Design of drainage systems must be matched to the roof construction and catchment area.
A green roof is an additional roof system on top of an existing roof made up of a layer of planted vegetation.
Moisture will be lost to the atmosphere as a result of evapotranspiration during dry periods.
This makes for lush plant growth on relatively thin substrate layers.
There are two main forms of green roofs intensive and extensive.
Intensive roofs take more time to manage as they can hold up to 150 pounds of vegetation per square foot.
Integration with hard landscapes for example walkways terraces driveways or play areas etc.
