Here are some questions that architects commonly ask us about NEDLAW Living Roofs™:
What types of vegetation are used?
What types of living roof systems does NEDLAW install?
What component materials are included in a layered living roof system?
Is the growing medium essentially topsoil?
Are living roofs more susceptible to leaks or breakdown of the membrane?
Is a new roof membrane required before an installation?
What types of roof decks can you install a living roof on?
What is the weight load of a NEDLAW Living Roofs system?
What is the R value of the system?
What about the warranty?
What are the conditions of warranty?
What is the cost?
What maintenance is required?
How many Living Roofs has NEDLAW installed?
Can a living roof system be applied towards LEED designation? If so,
what points can be awarded for a NEDLAW system?
What types of vegetation are used?
There are two general types of vegetation used by NEDLAW Living Roofs. Succulents,
such as sedum or stone crop, are a common type of plant used on living roofs
in North America and Europe. Sedum is a ground cover commonly found in alpine
regions characterized by harsh climates, which makes these plants suitable for
rooftop growth. Our pre-grown sedum include eight to ten species that are decorated
with both bright and earth-tone colors.
The second type of vegetation used is native meadow and prairie species. This
mat consists of twenty different species of prairie grasses and wild flowers
that are indigenous to Southern Ontario. These plants flower throughout the
summer and provide a mixture of bright colors. Like sedum, this native vegetation
is found growing naturally in tougher conditions where soil and moisture are
both limited, which makes it ideal for rooftop conditions.
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What types of living roof systems does NEDLAW install?
NEDLAW Living Roofs typically use a layered living roof system as it provides
greater flexibility in design and application compared to a modular system.
However, we can produce and install modular systems if requested.
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What component materials are included in a layered living roof system?
No matter the type of roof that you start with, there are seven general layers
that typically compose a living roof: the structural support, roofing membrane,
a root barrier, drainage, a filter, growing medium, and vegetation.
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Is the growing medium essentially topsoil?
No, the growing medium is a specially formulated light-weight mix designed for
high water-retention capacity and a low density. Once in contact with moisture,
the growing medium’s binding agents are activated to prevent soil loss
due to wind and water erosion.
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Are living roofs more susceptible to leaks or breakdown of the membrane?
No. In fact, a properly constructed living roof will extend the lifespan of
your roof membrane, often by 30 to 50 years.
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Is a new roof membrane required before an installation?
It’s very important to verify the integrity of the membrane before installing
a living roof. If the membrane is still in good condition and is at less than half
its expected lifespan, the membrane will not need to be replaced. However, if
the membrane is in poor condition or over half its expected lifespan, the membrane
should be replaced.
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What types of roof decks can you install a living roof on?
NEDLAW Living Roofs systems have been built on steel, concrete and wooden
roof decks.
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What is the weight load of a NEDLAW Living Roofs system?
Weight load can vary significantly depending on the soil depth used. Our sedum
Living Roof system requires as little as one to two inches of growing medium
or as much as four inches. Accordingly, weight can vary from ten to twenty pounds
per square foot. Our Native Meadow Living Roof system requires four to six inches
of growing medium for a weight load of between twenty to thirty pounds per square
foot.
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What is the R value of the system?
The R value of our Living Roofs range from twenty to fifty, depending on the
depth of growing medium.
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What about the warranty?
The NEDLAW Living Roofs standard warranty guarantees: the workmanship
of the installation for the life of the membrane, that all components of the
landscaping system will perform as per spec for the life of the membrane, as
will all vegetation from the date the installation is completed.
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What are the conditions of warranty?
NEDLAW requires that all maintenance be conducted as per specification and that
it be carried out by NEDLAW Living Roofs or a NEDLAW Living Roofs-certified
installer. Any removal and replacement of the living roof, due to other work
required, must also be completed by a certified installer.
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What is the cost?
The cost of a NEDLAW Living Roofs system varies depending
on materials required and the detail of the work. In general, prices can range
from $8/sq. ft to $50/sq. ft. On average, prices range from $10 to $15/sq. ft.
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What maintenance is required?
It’s a misconception that living roofs require no maintenance. All NEDLAW
Living Roofs systems come with a full two-year maintenance package. See Service
for more details.
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How many Living Roofs has NEDLAW installed?
According to a 2007 industry survey, NEDLAW Living Roofs systems accounted for
twenty-five percent of all living roofs installed in Ontario. By the end of
2008, we will have installed over 70,000 sq. ft. of Living Roofs.
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Can a living roof system be applied towards LEED designation? If so,
what points can be awarded for a NEDLAW system?
Yes, the installation of a NEDLAW Living Roofs system can be applied towards
LEED designation, and will play a role in the following points:
Sustainable Sites:
SS 6.1: Storm-water Management – Rate & Quantity
SS 7.2: Heat Island Effect: Roof
Water Efficiency:
WE 1.1: Water Efficient Landscaping: Reduce by 50 %
WE 1.2: No Potable Water Use or No Irrigation
Energy & Atmosphere
EA 1.1: Optimize Energy Performance
Materials & Resources:
MR 4.1 & 4.2: Must contain 7.5 % to 15 % recycled content
MR 5.1 & 5.2: Must consist of 10 % to 20 % regional materials
Innovation & Design Process:
ID 1.1: Innovation in Design
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