Our employees at Sky Garden often get asked the same question: how much does a green roof cost per m2?
Unfortunately, this question does not have a straight forward answer!
Although green roofs seem straight forward, there are many factors that can affect the cost of a green roof. Once you know these factors, you will have a better understading of how green roofs are priced and how much a green roof will cost per m2 for your specific project.
Green Roof Size
The size of a green roof can vary the cost per m2 of the system greatly. Larger projects benefit from economies of scale in delivery and materials needed for the green roof system.
For example, the delivery cost per pallet decreases as the number of pallets needed increases. This saving is carried across the overall cost of the green roof, leading to a lower cost per m2.
Type of Green Roof
The type of green roof system plays a part in the cost per m2. This is down to the different materials that are needed within different systems, and the quantity of these materials required.
A standard bio-diverse green roof system does not require pre-grown vegetation, which can lead to a saving. A sedum blanket system requires less growing medium than a wildflower blanket system. A green roof cost per m2 can change significantly with just a different choice in system.
Unfortunately not much can be done to change this factor.
Logistical challenges for the delivery of a green roof system may lead to a cost increase. For instance, a delivery location in the centre of London may not be suitable for a large delivery vehicle. A higher number of smaller vehicles would be required which increases the cost of delivery.
When asking how much does a green roof cost per m2, the inclusion of labour can make an incredible difference to the overall price of the project.
It has become a legal health and safety requirement for at least two workers to be on a green roof installation, no matter how small the project is. In some cases, this labour cost could double the cost per m2 of a green roof.
Installation of a green roof is straight forward. If you are looking to have a small green roof installed, it may be worth watching how to install a green roof, ordering the materials via our green roof shop and have a go yourself.
It is well worth checking exactly what is included in your green roof quote, or what is needed before getting your quote from a green roof company.
If you have a parapet around your roof, you will not need an aluminium edge retention detail. If you have access to your roof and are happy to water it yourself, you will not need an irrigation system for the green roof.
It is always worth going through your quotation carefully to see what is included or excluded in your green roof cost per m2.
As you can see, answering how much does a green roof cost per m2 is a tough one! Our advice to you would be to research the type of green roof you require, the size of the green roof needed and any extras you think you may need. Once you know this, a green roof company should be able to give you an accurate green roof cost per m2.