In addition the weight also depends on the water buffering capacity of the drainage layer.
Sedum roof weight.
In addition the weight also depends on the water buffering capacity of the drainage layer.
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A standard sedum roof has a saturated weight of about 80 kg m.
When using a biodiverse vegetation such as a mix of sedums grasses herbs plants and nectar plants the weight of the green roof is about 150 kilos m2 because a thicker substrate layer is required.
Here s a guide comparing types.
Weight of standard sedum roof.
Weight of standard sedum roof.
Typically the total depth of the green roof would be 85 100mm 12 20mm drainage layer 70mm of substrate and have a saturated weight of approx.
Individual complete modules are installed quickly and have a 90 fully grown sedum layer for instant greening.
If necessary this weight can be reduced to approximately 40 kg m for roofs that can only bear a lightweight green roof system.
The thicker the substrate layer the greater the weight of the total roof structure.
When sedum vegetation is applied to a green roof the weight is approximately 30 kg m2.
These provide aesthetic interest and diversity.
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.
Roughly speaking extensive green roofs have a substrate thickness of between 4 and 15 cm and a weight of 30 to 220 kilo per m2.
If necessary this weight can be reduced to approximately 40 kg m for roofs that can only bear a lightweight green roof system.
A standard sedum roof has a saturated weight of about 80 kg m.
When sedum vegetation is applied to a green roof the weight is approximately 30 kg m2.
Extensive built up.
So in dry state 50 m2 traditional green roof weighs around 5 tons while a similar sized urbanscape roof weighs just 1 ton.
Plugs or cuttings for plant material weight.
Sedum roofs with a natural drainage layer are designed to maximize water retention while sedum roofs with a synthetic drainage layer may focus more on minimizing weight.
Low weight can be crucial for huge building structures and retrofit projects with limited roof loads.
The weight of a green roof is one of a number of factors specifiers need to consider when deciding which roofing system to use.