Green roofs are unique environments, so you can’t just throw a batch of soil up there and call it good. What media should you use instead? And does it need to be customized or not? We answer those questions here.
Thinking about a green roof? There are a lot of factors to consider, as you already know.
What will you plant? How do you want it to look? Can you, like, eat breakfast on it and stuff?
Well, that all depends. Not only on your space and your vision, but on what kind of plants your particular ecosystem can support and the benefits you hope your green roof will achieve.
And that in turn depends a lot on the media you use.
Many people ask us whether or not they need custom media for their green roofs, so we thought we’d take a crack at answering that today.
What Is Green Roof Media?
At this point, most people understand that to build a green roof properly, you’re not going to just chuck some topsoil up there. Not only is that a waste of valuable topsoil, there are other constraints, including:
- The loadbearing capacity of a roof, which often can’t support the weight of true soil, especially when saturated
- The necessary water-retention and detention capacity of media
- Nutrient requirements of plants
- The tendency of topsoil to compact when exposed to the demands of a green roof environment, and the difficulty of loosening it once it does
Instead, we rely on green roof media. This ranges hugely, from expanded shale and clay to pumice to mineral wool and other fabrics. Many of these are available as premade substrates that you can buy from green roof supply companies or that your contractor will source for you.
However, in some cases, you may wish to go with a custom green roof media.
Why Would You Want Custom Green Roof Media?
Although many green roof projects can go with an off-the-shelf variety, there are a number of reasons you might go with a custom blend. This is true if you:
- Have particularly exacting weight constraints on your roof
- Are hypersensitive to the use of plastics in your green roof
- Have high drainage requirements or otherwise demanding detention and retention needs
- Use plants with certain requirements for what they’ll grow in
- Are planning an intensive green roof, with media depths of up to 2 feet or so
- Have a pitched or sloped roof
- Are using a specific water retention layer that demands a custom green roof media
If this is the case, it’s time to consider custom green roof media. Here at Ecogardens, we have a number of ways of taking care of this. We might involve a soil scientist, for example, or ask our media vendors to create something that takes the exact needs of the roof into account.
Would you like to learn more about custom green roof media and how we can help you? We invite you to get in touch today!