Green Roof Installation

January 12, 2015


Green Roof installation guide
At Eco green roofs we provide a complete installation of green roof systems, we work with roofing contractors on a daily basis and have grown our teams to over 12 teams on the road working everyday.
All of our green roof installers are trained to work on roofs and understand the importance of looking after the waterproofing below. We are the only green roof company where all of our green roof installers actually work for the company and are not subcontracted out or agency labour.
This allows Eco green roofs to have complete quality control over our supply and fit installations.
We also offer a supply only service and we send a full green roof installation guide with a helpline number to ensure a simple green roof installation.
When you are installing a green roof the first thing you must do is ensure the waterproofing membrane is suitable and in good enough condition to have a living roof over it.
Most new products on the market are suitable for green roofs and many manufacturers offer a protection or separation layer with their products.
The first thing to do is to brush off any debris from the roof. Once you have a clear surface roll out your drainage layer with the filter layer facing up. The drainage board ensures your roof drains freely, and the filter layer is in place to stop the fines and nutrients leaching from the green roof growing medium. Many of the green roof companies offer very deep drainage boards and try potential scare clients and use the word drainage to sell deeper boards for higher prices.
The drainage layer is important so that the system does not become water-logged during storm-water events and therefore prevents root rotting of the green roof plants. The drainage layer has also been adapted to retain more water in some cases, where water can be stored in egg-cup shaped boards for plants to access in times of drought stress.
At present there are many conflicting research papers that have tested the effectiveness of the different drainage boards currently on the market. At Eco Green Roofs Ltd. we stay up-to-date with the latest academic research to make sure we are providing the best possible green roof systems. At the moment the view is that cup based systems that hold water maybe detrimental to plant growth as the large void space (during drought periods) acts to dry out the substrates further. It is thought that the warm air within the voids will pull water out of the substrates (as water potential moves from regions of high concentration to low concentration) when the system is extremely drought stressed.
For this reason we are using a small stud board that will allow the green roof to drain freely and reduce any water stagnation during very wet periods but will not create large voids that maybe damaging to plants in very dry months.
The next layer is the growing medium this is undoubtedly the most important part of the system. This layer comes in different depths depending on the green roof system and the vegetation that needs to be supported. At Eco green roofs our Technical Director Dr Chloe Molineux holds a PHD in green roof substrates (growing medium) so we are in a unique and lucky position to be able to design individual substrates for different plant species, and different habitat creations. We actually bend different substrates to suit different plant species. Most green roof companies use generic mixes that have no real flexibility or speciality to them.
When you order a green roof with us we will automatically send you the exact amount of growing medium you require and all that is needed is you to equally spread the green roof growing medium.
The final stage is the vegetation this will come depending on your roof type. If it is blankets you will receive fully developed fully established turf rolls of either Sedums, wildflowers, herbs or grasses. If you have plug plants you will receive the exact number to populate your green roof, these usually come in 20 plugs per meter square.
The only other things you may need to be aware of is the numerous accessories that come with a green or brown roof. One of the most important things is a 20/40mm river washed cobbled edge, this is generally installed 300mm -500mm from around the perimeter of the roof and any roof lights or penetrations. This is to act as a firebreak for the green roof, although most green roof plants are succulents so it would be highly unlikely for the roof to ever catch fire.
An aluminium green roof edge can also be installed and is also often specified, this can be used to contain the green roof system, or this can be used to create an up stand around the roof.
On brown and bio diverse roofs you are trying to create a broad range of habitats to create a haven for various species of wildlife. We introduce logs,boulders, sand piles, rope, bat boxes and bird boxes. We actually just installed a Peregrine falcon box which had a cost price of over £2000!!!
So in short here is your quick stop check list to install your own green roof.
1. Clear and clean the roof
2. Roll out the green roof drainage board with filter layer up
3. Equally spread the growing medium rake if required
4. Roll out turf, or plant plugs
5. Add all accessories
6. Enjoy your brand new green roof
*Please note this is only a guide