There are many good green roof systems available on the market today. Both tray systems and mat systems are widely popular. Pre-filled soil bags for the roof and other green roof designs are also available.
With so many choices, how do you know what system will be best for your green roof project?
I am going to offer a few suggestions here.
Importantly, you should first talk with licensed knowledgeable professionals in your area. Make sure you talk to roofers that have been doing business in your area and have a solid reputation.
Just as important, make sure you involve a local landscape architect for plant selection.
Ultimately your installation should be completed by those who have experience with green roofs. This will involve a company or team that is knowledgable about both roofing systems and plants.
A roofer that doesn't know plants may put on a good roof system but your plants may die soon thereafter if he or she doesn't understand how to choose the appropriate plants.
A landscaper may have a solid understanding of what plants are more likely to survive the harsh roof conditions in your area, but may not be licensed to install those plants on a roof, or may damage the integrity of your roof during inappropriate installation.
A successful green roof requires a team of professionals. A good green roofing team can help you select the type green roof system best suited for your geographic area, your cost and your project requirements.
The above photo, for instance shows a green roof mat being installed over white roofing TPO (thermoplastic olefin). We will discuss TPO as a green roofing component in another blog entry. Due to TPO's stability (TPO contains a significant amount of stable polypropylene - ppe) the material is used frequently in roofing (and may make for a good root barrier in some applications).
Mat-based green roof systems have different preferred applications than tray systems. Both have their place in Green Roofing.
Here in Florida, plants tend to grow quickly due to the extended growing season (some year-round) and mild climate. Mats tend to allow plant root systems to grow radially all they want to. Mats also allow the plants to 'move' across the roof over time until they find just the right spot for the species' requirements.
Another advantage of the mat system is it's light weight profile and interlocking ability to allow roots to grow through the mat weave - holding plants in place during storms or on slopes.
Again, your green roof project should involve a number of team professionals - those who understand plants and those who understand roofing.
As always, email me with your green-roofing questions and I'll use your questions here on the blog to help share green roofing data and information!
Happy Green Roofing!