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Here we have a green roof. What I want to do is take you back
and explain how we got to this stage.
Today we have the Green Roof Project. The size of the green roof is approximately
20' x 26'. What we're going to be showing
you is the stages.
The first stage that we are going to get into is
putting down the root barrier. But before we do that we are going to be blowing off and
cleaning the entire surface.
There are no special preparations for the roof.
It's a torch-applied waterproofing that has been put down and then you will see the stages as we go on.
What we're showing here in this clip
is the actual waterproofing on the deck. As you can see here,
nothing special has been done. It's a torch-applied waterproofing
on top of the deck. It has been swept, it has been cleaned and it has been blown off
to get rid of any debris that was on top of it.
And from this point we're going to put down our root barrier.
What we're doing right now is rolling out our root barrier.
The root barrier is a polyethylene membrane.
typically 10 mil. Here is the drain spout, and what we're doing now is cutting an
opening for the drain spout.
Typically you cut a cross-section and push it down.
Once we have cut the X we are going to cut around the drain spout
nice and tight, all the way around.
Be sure not to cut into the waterproofing membranes below.
When cutting the root barrier be sure that you leave enough overlap
so that you can tuck it
underneath the parapet so that you cover the
actual waterproofing.
What we have here is the Cosella-Dorken DELTA-MS 20 (DELTA-FLORAXX).
DELTA-MS 20 means
20 millimetres dimple-height. As you can see they are
large cones which are
specifically designed for water retention, so the cups do fill with water.
What we have here
is perforations for the DELTA-MS 20. These perforations are designed
to allow water to flow through in case of overflow and too much rain.
DELTA-MS 20 perforated
comes in 2m x 20m rolls.
What I'm going to do now is lay the product down and roll it out.
Now that we have the DELTA-MS 20 down on top of the root barrier
we're going to roll out the product. As you can see I can stand directly on top of it
without affecting
the dimple configuration.
When you come to the end of a roll and you have to start
another roll, all you have to do is overlap the DELTA-MS 20 by 2 dimples
as I am showing right here.
I just finished laying down the DELTA-MS 20.
The next stage is to put down the geosynthetic fabric.
The reason why we're going to put down the geosynthetic is because we want to
maintain the cups free from
growing-medium so that they can fill up with water, but they
are not filled up with growing medium. What we recommend to use
is a geosynthetic with a weight of 4 ounces per square yard.
The reason why we chose a 4 ounce/sqyd fabric
is because we want to ensure that you have proper drainage so that the
soil particles from the growing medium do not clog up the fabric.
What we're showing here
is the assembly with the DELTA-MS 20
and the geosynthetic on top. The reason why
we have brought it to this point right here is to protect the waterproofing.
Riverstone will come right at this point,
but growing medium will not get behind and therefore cannot clog up the air gap.
So this is the reason why we actually put it all the way up to
where the root barriers is. So now we are going to
cut out the drain from the geosynthetic. I will cut an X which
I have already prepared.
I am going to push the fabric down.
We are going to take the fabric and tuck it underneath just like so,
and around the drain
what's going to happen is you're going to install your riverstone.
So we want to make sure,
by having the geosynthetic here in the riverstone
all the way around, we want to make sure that the
the particles from the growing medium
do not come in and clog the drain.
What I have done now is
I put down a little bit of gravel rock that is gonna go all the way around the
outer edges.
I just put a little bit down, just to hold the fabric so it doesn't blow away.
What I am showing here is the riverstone around the drain. Below the riverstone
we have the geosynthetic,
the DELTA-MS 20 and the root barrier. Again, the idea behind the riverstone
is to make sure that the roots from the plants
cannot come in and clog up the drain.
We are going to stop here and go over the steps that we did before.
We began with the waterproof deck. Then we laid down the root barrier.
The root barrier was a 10 mil polyethylene sheet that came underneath the stone and
up to the parapet.
Then we put the DELTA-MS 20 on top of
the root barrier. The DELTA-MS 20 finished
right at the corner. On top of that we put the
geosynthetic that has come in and
up to prevent any growing-medium particles from getting in behind
and to protect the edges, so that the
roots from the plants
cannot grow over, we put the bed of
riverstone. Typically we put the 14" of riverstone
from the parapet out, sloped towards the growing medium.
Now I am going to take
buckets of riverstone and basically lay them just like so.
You always want to cover this area in such a way so the UV
does not destroy the geosynthetic or the root barrier that's in behind.