Typically a basic lightweight green roof will weigh between 60 to 150 kg per square metre which will increase when saturated with rain or snow.
How much does a green roof weigh.
They can be specified to meet local biodiversity action plans or to support specific flora and fauna including bats bees butterflies birds and so on.
Weight of standard sedum roof a standard sedum roof has a saturated weight of about 80 kg m.
Check that there are no areas of damp rotting wood.
If necessary this weight can be reduced to approximately 40 kg m for roofs that can only bear a lightweight green roof system.
When saturated with water in the summertime when the plants are at their biggest and heaviest the mats weigh 40 45kg m2.
A semi intensive green roof weighs between 30 50 lbs per square foot.
Thus the saturated weight of a 3 inch deep system is about 20 pounds per square foot including a mature plant cover.
For example roofmeadow green roofs engineered to be both lightweight and efficient generally weigh about 6 75 pounds per square foot for each inch of media depth.
How much does a green roof cost.
Intensive green roofs are essentially roof gardens and may also need to allow for the additional weight of paving and terracing furniture and even trees.
System depth dry weight saturated weight 5 25 media depth 17 22 lbs ft 2 29 34 lbs ft 2 6 media depth 19 25 lbs ft 2 33 39 lbs ft 2.
So in dry state 50 m2 traditional green roof weighs around 5 tons while a similar sized urbanscape roof weighs just 1 ton scale this up and a 1 000 m2 traditional green roof space requires 100 tons of material to be brought on the roof and the urbanscape version only 20 tons and can be called a light weight green roof.
The weight of biodiverse green roofs varies according to the needs of the plant species required.
An interesting example of an intensive green roof is manaton the award winning private house on dartmoor that uses local meadow grass to blend the family home into the landscape.
On average an extensive green roof weighs between 10 30 lbs per square foot.
Biodiverse green roofs are low maintenance roofs designed to create or replace natural habitats.
Holds up to 9 litres of water per square metre so saturated weight is 9kg m2.
A flat roof built using the enviromat green roof system will weigh the following.
Let s crunch some numbers.