Thank you for all the comments on the blog post:
We believe a lot of people in North
America agree with the comment that in some areas Green Roofs can't thrive without irrigation. We at Green Roof Technology don’t disagree nor agree. Allow us to bring the
discussion into a fundamental perspective:
Before you built a structure, you have to remove nature or
simpler living plants that nobody watered before. Modern green roof technology
is able to mimic this type of environment and allows to promote exactly this
drought tolerant and hardy vegetation. With a little more understanding of this
technology, it is even possible to increase the plant varieties or the plants
Nevertheless the attractivity might not
meet the expectations of us (humans). Our picture in mind of a roof garden is a
lush green vegetation form that is created with plants that please us (humans),
that are not poison or dangerous. In some areas we can achieve this goal by utilizing
resources that haven’t been available at this location before the structure was
By using natural resources (and water is the most valuable)
we start changing our environment (we take water away from somewhere – from plants
somewhere) just for our own comfort. Understanding that and the value of water
should create an awareness to green roof professionals or engineers to design
modern green roof technology in a way that no water or super highly restricted
amounts of water are utilized.
Unfortunately, the irrigation industry and most of the green
roof designers grew up in an environment where resources are endless. With that
said the current waste of water on green roofs is simply not acceptable to me
and in these cases green roofs are an environmental nightmare - just for our
pleasure (and cash) and that things look “nice and green”.
When I drive around in neighborhoods in San Francisco in the
morning, my car is being washed by all the sprinklers and nobody has a problem
Simple and efficient technology is here since many decades but
not in the interest of the industry, nor “re-invented” in the US or there is a
lack of common sense – maybe it is a combination of all.
Most issues I am confronted with, are a result of high tech
irrigation that is just not doing what it is supposed to do, there is not the
right app, poorly designed and installed, too complicated for facility people
etc. or simply drains the budget of building owners over time this water costs
are going up.
Let’s discuss further and email us directly: firstname.lastname@example.org
Comment by Jure Šumi ((LinkedIn):
Response Jörg Breuning:
Thank you Jure.
My starting point of thoughts about irrigation on extensive
green roofs goes back to a fundamental point and only a handful people make
Humans are capable to replace nature with a manmade structure
on any location on Earth and they make it suitable for people to live there. In
these fundamental thoughts, I expect that humans are also able to create this
lost part of nature on top of these structures.
I agree this is not always cheap and not everybody is
blessed with creativity or experience. Nevertheless, it is possible and it is
our responsibility if we respect nature.
The rooting depth of plants is certainly a key element - it
isn’t a road block. It seems it is the preferred excuse that we don’t need to
feel responsible in what we re doing and that we don’t feel guilty.
I also think it using water for cooling buildings in an open
system (what any green roof is) is considered - in my world - using elementary,
limited and precious resources for our convenience. In the case that producing
water (in dessert states) for the wasteful irrigation of plants (to make our
close environment nice) might be a problem to justify to more than 100 million
people that have no access to dependable water resources.
What I am saying is, that growing plants even in areas where
plants would hardly grow can be done with extremely low impact on natural, precious
resources at costs that are lower in the short or long term. The current hype
for green roofs can create significant drawbacks in 15 or 20 years from now to
building owners if the costs of water continue to rise. Keep in mind a 20 year
old green roof is not even the half of the life span of a green roof (at least
that is what I know from experience).
Professionals need to start thinking long term
and not for quick profit, they should disregard fancy fashions or get away from
desperate LEED point collecting terms if they seriously respect nature.
Picture: Deep rooting plant on roof with hardly any soil and never intentially planted (in Texas at the border to Mexico).