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.

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.

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.

Is the growing medium essentially topsoil?

No, the growing medium is a specially formulated lightweight 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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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

Is the growing medium essentially topsoil?

No, the growing medium is a specially formulated lightweight 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.

Are living roofs more susceptible to leaks or breakdown of the membrane?

No. In fact, properly constructed NEDLAW Living Roofs will extend the lifespan of your roof membrane, often by 30 to 50 years.

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.

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.

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.

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.

Can a living-roof system be applied towards LEED designation? If so, what points can be rewarded 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

For more information, visit Canadian Green Building Council.

What types of vegetation are used? Do they flower throughout the growing season?

There are two general types of vegetation used by NEDLAW Living Roofs. Succulents, known 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. 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.
These plants flower throughout the summer and provide a mixture of bright colors.

What are main benefits of a NEDLAW Living Roofs system for the building and its tenants?

Again and again, Living Roofs have proven to bring a wide range of economic, social and environmental benefits to building owners and tenants, including:

• Energy savings as heat transfer is reduced between the building and its outside environment
• Reduced life-cycle capital costs
• Reduced costs for roof maintenance
• Additional amenity space for tenants that did not previously exist
• Enhanced aesthetics of a building with added green space
• Improved psychological benefits, as people are happier when exposed to or have access to greenery
• Increased real-estate value, as buyers are willing to pay more for access to or a view of green space.

What maintenance is required?

It’s a misconception that Living Roofs require no maintenance. All NEDLAW living-roof systems come with a full two-year maintenance package. See Service for more details.

What about the warranty?

The NEDLAW Living Roofs standard warranty guarantees the workmanship of the
installation for the life of the membrane, and 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.

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.

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.