Frequently Asked Questions About Green Roofs
There are some things about green roofs that everyone needs to know before they start on a project. I hope that you can find the information you need, on this page, but if not, please don’t hesitate to contact us. Our friendly customer service team can usually find the answers to your questions.
- How much does a green roof weigh?
- What does a sedum roof cost?
- What is the depth of a green roof build up?
How much does a green roof weigh?
For the Enviromat green roof build-up described on this website, please allow for a loading of 120Kg per square metre. Should you be using a different green roof build-up, remember that the more growing medium you use, and the bigger the plants that are established on the roof, the heavier your green roof will be.
The standard Enviromat green roof build-up using drainage mat, water retention mat and Enviromat sedum matting has a saturated weight of up to 60Kg per square metre BUT, when designing your green roof it’s important to allow extra strength for live loading ie for snow, or for somebody walking on the roof to install or maintain it. We recommend that your roof has a minimum load bearing capacity of 120Kg per square metre if you are using the standard Enviromat green roof build-up
What is the depth of a green roof build up?
There are many different ways to make a green roof but if you choose to use the Enviromat green roof build-up, you will be adding three or four layers (depending on the slope) of blanket to the roof.
For a flat green roof, you will need on top of your waterproofing; a polyethene root barrier, a drainage mat, a water retention fleece and Enviromat sedum matting. The combined depth of all of these layers is 45-50mm
For a pitched green roof, you will need a polyethene root barrier, a water retention fleece and Enviromat sedum matting. The combined depth of all of these layers is 25-30mm
What is the cost of a sedum roof?
This is a difficult question to answer as costs can vary enormously according to access, size, who is doing the work, the design of the edgings etc etc etc