Roof Tops Going Green
Overpopulation and the development of natural land into built-up areas have led to severe concerns over the environment, specifically, the imbalance that we are causing by removing sources of oxygen—plantlife—while increasing sources of carbon dioxide—industry and, well us.
While there will always be people who don’t care or even don’t believe there is a problem, many look to improve the situation in any way they can, however small an impact it might have. Green roofs have proven to be a way in which people, from individuals to large corporations, can do something to help ease the burden we are placing on the environment.
A green roof is a roof that is partially or entirely covered with plant life and serves several purposes on a rooftop, such as absorbing water and providing additional insulation against the external temperatures.
The term “green roof” may also refer to a roof that utilises various green technologies to save on energy use; however, this is a less common use of the term, with those types of roofing often being referred to as eco-roofs.
What are the Benefits of a Green Roof?
The natural follow up question to “what is a green roof?” is to ask what the benefits are. Beyond the obvious benefit of creating a small patch of carbon dioxide removing, oxygen-producing nature, there are actual benefits to the structure itself.
The first of which is the insulative properties of the green roof, which can help to keep the interior of a building warm during colder weather by keeping the heat in, while also working to keep the interior cooler during the hotter months by keeping heat out.
Green roofs also absorb water, which can help with drainage. Perhaps one of the more underrated benefits of a green roof is the positive effects it can have on the employees or residents of the building it is on.
If the building is relatively low, so that the green roof is visible from the ground, or if the green roof is accessible so that people can walk around it, it can markedly improve the mental health of those around it—particularly if the building is in a heavily built-up area, such as the centre of a large city, where nature isn’t perhaps as prevalent as it should be.
On a larger scale, green roofs improve the surrounding air quality and reduce the “heat island effect” of large urban areas. They also make an excellent little habitat for wildlife, which can help reduce the stress that our continued expansion places on our animal friends.
It is unlikely that anyone reading this will be unfamiliar with how removing plantlife can negatively affect the environment, but the basic explanation is that plants produce oxygen, and we need that oxygen to live. Every tree we cut down, every field of grass we concrete over, is a source of oxygen we no longer have.
The fibres are small and embedded into the concrete facing in all directions. This ensures the reinforcing effect of the fibre is effective regardless of the direction any forces are coming from.
Fortunately, the natural world is effectively a two-dimensional plane. No, we’re not saying the Earth is flat, but you very rarely find situations in nature where plant life is growing above other plant life. Forests may seem like an example of this very thing, with plenty of nature going on under the canopy of the trees. But even there, the trees themselves are rooted in the same floor as the rest of the forest’s flora.
What this means in practical terms is that if we remove a patch of grassland in order to build a skyscraper, but we then convert the roof of that skyscraper to a green roof, we will have reclaimed a lot of the lost benefits of the original grassland.
There are limits, of course. For one thing, it is not feasible to reclaim 100% of the land that was lost in the construction of whatever structure is being built—there will always be areas that can’t be made green for structural or convenience reasons. It is also challenging to plant things like large trees on a green roof, since they need a lot of soil depth to grow, and will weigh a considerable amount when mature.
These are only shortcomings when you compare them to the original patch of untouched land, however. When compared to a natureless concrete structure, a green roof is lightyears ahead of the alternative.
How Are Green Roofs Made?
There are many ways to make a green roof, but the same basic principles are involved. Firstly, the structure needs to be strong enough to support a green roof. The weight of soil should not be underestimated, particularly when it gets wet.
The next step is to ensure the roof is thoroughly waterproofed since any leaks will be considerably harder to repair once the green roof has been laid down. From there, various membranes need to be laid down, such as root barrier—which prevents the plants in your green roof from ingressing into the structure of your building—and drainage membranes—which channel water to any desired spots, preventing it from pooling and adding unnecessary strain to your roof.
Next up, you would have a filter layer that should prevent things like soil from getting into the channels of your drainage membrane. After that, you are ready for your growing substrate. In a regular garden, this would be soil. However, there are other options when it comes to a green roof. Indeed, the soil is often an inferior choice for this purpose. Be sure to research what you intend to grow before choosing your substrate since the intended plantlife will change what the best substrate is.
Finally, you are ready for your vegetation. Of course, you could plant anything up there, but certain plants are more suited than others. These tend to be hardier, low maintenance plants that will be able to endure the occasional minor drought.
For green roofs where the appearance is not crucial, mat-forming plants are particularly popular, as they achieve excellent coverage and require very little in the way of help to get going. As you might expect, different plants are better suited to different roofs, so look into which plants are best for the kind of green roof you want to build before buying.