|
Although the initial cost is slightly more than a traditional roof, the extra cost is recouped over a period of time in
several ways.
Firstly, covering the roof membrane with a blanket of soil prevents
heat build-up, and prolongs the life of the roof by 50% . . .
. . . This enables a traditional membrane system that
carries a 30 year warranty to last 45 years!
In turn, this keeps the old roof out of the landfill for another 15 years. The layer
of soil over the roof also protects the roof from severe weather, thus ensuring
the longevity of the membrane system.
The second and most significant advantage to green roofs is their ability to remove
heat from the structure they are covering, thereby reducing air conditioning
costs by up to 85%!
There is also a considerable amount of insulation value, with opinions as to how
much effective R value varying between R5 and R10.
In some cases more advanced systems are being developed into actual commercial farming
projects, or residential garden plots. Obviously there cost-reduction is in not
having to ship produce and better quality control over the end produce.
Roof gardens provide water retention, which in turn relieves stress on overburdened
civic drainage systems, and help prevent flooding. They also provide a wonderful
habitat for pollinators and birds while beautifying the area and removing carbon
from the atmosphere.
The sky's the limit when it comes to designing green roofs (pardon the pun),
as virtually anything you can do with ground landscaping can be done on the roof
as well. Suffice to say, the more complex the design, the more costly the project.
WHAT DEFINES A GREEN ROOF?
A green roof is a structure containing engineered soil and plants, which is
constructed over an existing roof. Most are constructed on low slope roofs
(I.E. slope of about 2%), but can be sustained on slopes up to 40% or greater when
measures are taken to prevent soil erosion.
A green roof structure consists of four major layers: 1) drainage board; 2) water
retention product; 3) root barrier; and 4) growing medium . . . and it
is best to work with a roofing contractor that uses a single source supplier that
provies a warranty covering the entire roof structure. That is why Apex
Exteriors works with Soprema, a recognized
world leader in roof protection systems and green roofing innovation.
Soprema introduced rooftop gardens to Canada and thanks to years of research and
an international team of experts, Soprema has now developed six systems for rooftop
gardens that range from the plain to the exotic. These designs can be installed
on all types of roofs (even on slopes up to 45 degrees), using inert materials
that do not affect the environment.
For example, Soprema's engineered soil mix is 100% organic, and
requires very little maintenance. Soprema has also recently developed a wild grass
sod that can be installed with the green roof system to provide an instant green
roof, which eliminates the need to tend a seeded soil, and helps it become
established. Shrubs, trees, and flowers can be planted immediately right into the
sod.
There are some things to consider before embarking on a rooftop garden project;
probably the most important of which is the weight load. Rooftop gardens have considerable
weight and your building must be passed by an independent structural engineer to
show it can withstand the load.
One other important thing to remember is that rooftop gardens have to be reverse
engineered in the planning process. They are living systems and everything depends
on what you want to plant and what other goals you wish to achieve with your urban
eco garden.
Please contact us with any questions you may have, and happy planting!
|