Home/Frequently Asked Questions

BENEFITS

An employee-accessible rooftop garden may increase time available for breaks.

Extension of the lifetime of the roof; typical estimates are that a green roof potentially extends the lifetime of a roof between 200 and 300 percent, by protecting the rooftop from ultraviolet radiation, large temperature fluctuations, drying winds, and punctures.

Not only does the roof last longer, but there is reduced membrane maintenance. All this brings about significant cost savings over time. In some communities, storm water incentives may also bring substantial monetary benefits.

As the huge costs associated with stormwater runoff are becoming recognized and as smog and other pollution impacts our cities, many cities and states are encouraging “green” building methods, including green roof systems. By offering financial incentives for green roofs, municipalities help to reduce storm water surges, and therefore protect the ground water, lakes and streams, and encourage energy conservation.

Of course, incentives vary from city to city and state to state, but it is not uncommon for owners of buildings with green roofs to be generously rewarded.  The city of Portland, OR, provides financial, technical and educational incentives to participants through its green roof initiative.  Washington, Illinois, New York, Montreal, California and Maryland have also implemented incentive structures.  Cities all across North America are following suit, and grant money is often available for the energy conservation and air and water quality benefits that green roofs bring.  Be sure to check with your state and local governments. Don’t assume that nothing is available. States and municipalities benefit greatly from green roofs, and often provide tax credits, avoidance of fees assessed for impervious surfaces, grant funding, and/or favorable zoning to encourage their use.

Visit GreenRoofs.org for a list of some incentives, policies, and resources for green infrastructure.

Green roofs have been proven to bring about significant energy savings, particularly during the summer cooling season in which single story buildings can experience a reduction of greater than 25% energy use for air conditioning. Green roof soils insulate the roof from heat, and green roof plants transform heat and soil moisture into humidity, to create natural evaporative cooling. Each gallon of water transpired by the plants or evaporated from the soil surface liberates 8000 BTU of thermal energy.

In urban areas, impermeable surfaces (streets, sidewalks, rooftops etc.) dominate the landscape, preventing rainwater from following a natural cycle of absorption. Instead, as much as 75% of the rainwater runs into sewer systems carrying contaminates from the air and roadways (salt, oil, mercury, etc.). This water flows untreated into lakes and streams. In some cases, it may cause overflows of sanitary sewer systems, causing the dumping of untreated sewage (combined sewer overflow).

In contrast, LiveRoof green roof surfaces can absorb a substantial amount of rainfall reduce runoff, lessen the risk of combined sewer overflows and flooding, and to some degree filter the water as it percolates through the LiveRoof soil. Even when a rainfall is such that it can not all be absorbed by your LiveRoof, the excess rain that runs through the growing medium is filtered and delayed until after peak flows, which allows additional time for sanitary sewer systems to handle uncontrolled runoff.

In urban areas, impermeable surfaces (streets, sidewalks, rooftops etc.) dominate the landscape, preventing rainwater from following a natural cycle of absorption.  Instead, as much as 75% of the rainwater runs into sewer systems.  Carrying contaminates from the air and roadways (salt, oil, mercury, etc.), this water flows untreated into lakes and streams.  Older large cities often employ combined sewer systems, which can lead to untreated sewage release directly into local waterways during heavy downpours.  The detrimental effect of excess sewage release into local waterways often results in lowered property values, high cleanup costs or even hefty federal government fines to be borne by the local community.

In contrast, LiveRoof® green roof surfaces can absorb significant rainfall, lessen the risk of flooding, and to some degree filter the water as it percolates through the soil and as the plants take up certain heavy metals and nutrients.  Even when a rainfall is such that it can not all be absorbed by your green roof, the excess rain that runs through the media is filtered and delayed until after peak flows.  Because green roofs soak up much of the initial rain water during a storm, the municipal system has additional time to better manage the stormwater and reducing the likelihood of a combined sewage overflow (CSO).

Additional detention is possible when a blue roof system is used in combination with green roof.  LiveRoof modules elevated with RoofBlue risers on rooftops with control-flow drains may reduce the size of drains, need for cisterns or underground storage tanks, and the costs of stormwater utilities.

Plants, soil, and trapped air and moisture in the soil are great acoustic insulators.

Studies have shown that green roofs can reduce indoor sound by as much as 40 decibels, a benefit not lost on those that work close to overhead highways and airports.

Simply put, it is the temperature difference that exists between urban areas and their surroundings.  Urban areas tend to be from 7 to 10 degrees hotter due to the concentration of heat-absorbing buildings, pavement, auto-exhaust, and hot air from cooling systems.  The bubble of hot air that encloses cities is in large part due to lack of vegetation and is a great contributor to smog, ozone and dust (from artificially created air currents from the rising hot air).  The urban heat island effect has also been shown to create unique weather patterns, with inordinate drought, high winds and electrical storms being more common than surrounding rural areas.

Traditional rooftops are usually covered with tar, black membrane, shingles or stone. As a result, they absorb sunlight.  On sunny days with an air temperature of 95°F, city roofs can easily reach temperatures of 175°F or more. The LiveRoof® system acts like a protective umbrella above the roof to shade and insulate buildings, avoiding the heat island effect associated with traditional rooftops.

Plants, of course, release oxygen and evaporate water, and the soil they live in evaporates water. Collectively, these processes are known as evapotranspiration and act like evaporative cooling systems to make the surrounding air considerably cooler. By implementing a LiveRoof® system, the combined benefit of eliminating the heat generated by a non-vegetated rooftop, along with the evaporative cooling effect, is significant.

DESIGN

LiveRoof is most commonly used on well-drained, low and mid slope roofs atop industrial, commercial, institutional, governmental and residential buildings which can support the weight of the green roof.

Green roofs must only be installed on appropriately engineered buildings.

A green roof can wholly transform a space! The ability to retrofit for a green roof depends upon the structure’s ability to bear the additional weight load.  A qualified structural engineer should ALWAYS be consulted to determine safety prior to installation of LiveRoof modules or RoofStone pavers.

The LiveRoof Lite system was developed to expand the opportunities for green roofs on existing buildings.  With 2.5″ of soil, the system’s saturated weight is 15-17 lbs / sq ft.

Certainly—median strips, patios, plazas, and malls can be instantly landscaped with fully mature ground covers using LiveRoof modules.

Yes, normally this is done on rooftop patios where the load limits do not allow for the weight of 2 or 3 feet of soil in the planters. In this case, all but the top 4-1/2 to 6-1/2 inches of the planter is filled with closed cell foam, then LiveRoof is set on top to give the illusion of substantial soil volume.

Read more about lightweight green roof implementation on our blog post.

These LiveRoof modules are elevated with with EPS foam to reduce the overall weight of the roof.

The LiveRoof® system weighs approximately 27-29lbs./sq. ft. (with a media depth of 4”) when fully vegetated and saturated.  The LiveRoof® soil follows FLL standards, enhanced to reflect current research regarding sustainable organic content.  We have intentionally avoided excessive organic content, which will shrink excessively over time due to decomposition.  Likewise, we have avoided perlite which may break down during the freeze thaw cycle.

The best irrigation method is the one that most efficiently applies the water and provides the lowest lifecycle cost. In the case of green roof applications, this choice is straightforward and simple. Spray rotor systems are the least expensive to install, easiest to maintain, and apply water most efficiently. This may run counter to what is sometimes spoken about spray vs. drip or sub-irrigation, but it’s the truth and has been born out by testing at LiveRoof, LLC and research at Michigan State University.

Closeup views of drip, sub, and overhead irrigation.

Closeup views of drip and sub-irrigation emitters and layout of overhead irrigation system showing four of six emitters.

To understand why spray irrigation uses less water than drip or sub-irrigation systems on green roofs, one must realize that green roof soils are engineered to maintain their volume and last the life of the building, and therefore are different in composition and characteristics than nursery or natural field soils. Nursery and natural field soils are typically high in organic content. But, green roof soils are very low in organic content, to avoid volume loss via decomposition of the organic matter. In nursery and natural field soils, drip or sub-irrigation systems can often conserve water, because these types of soil are good at dispersing water laterally or wicking it upward by capillary action – through the absorbent and capillary qualities of the soil. But green roof soils, which are predominantly composed of inorganic aggregates, have poor capillary qualities and do not conduct water effectively in either a lateral or vertical manner. To irrigate them with drip irrigation, one must set the tubes so closely together that the cost is prohibitive. And, to irrigate them with sub-irrigation, one will use more water than spray irrigation and may risk root rotting diseases, from too much water saturation to the lower level roots.

Horizontal movement of LiveRoof substrate subjected to drip irrigation.

Representative horizontal movement of wetting front for Live Roof substrate subjected to drip irrigation after 5, 15, and 25 min.

Horizontal movement of LiveRoof substrate subjected to sub-irrigation.

Representative horizontal movement of wetting front for Live Roof substrate subjected to sub-irrigation after 10, 20, and 30 min. Orange flags show location ofsub-surface emitters.

A well-designed overhead spray irrigation system, very much like what would be used in a home or commercial landscape, provides even coverage to the surface of plants and soil at a very low installation cost. Such systems are simple and inexpensive to maintain, and apply the water quickly and efficiently. Studies by Dr. Bradley Rowe, PhD, and others at Michigan State University Department of Horticulture compare the effectiveness of drip, sub, and overhead spray irrigation methods, and the researchers found that drip and sub-irrigation systems wasted more than double the water lost in an overhead spray irrigation system.

Sedum growth by several irrigation methods.

Plant growth of Sedum album and Sedum floriferum subjected to overhead, drip, sub, and no irrigation following 12 weeks.

Images courtesy of: D.B. Rowe et al. / Ecological Engineering 64 (2014) 306– 313

LiveRoof’s project showcase contains volunteered projects from across North America. Submit your project today using our simple online form. Submit high resolution photos to sales@liveroof.com and/or call 800-875-1392, and you may see your project featured in our next design guide printing.

RoofStone follows the roof contour and can be used to create walkways, patios, and landing areas on most non-ADA compliant roofs.

RoofStone can also be used on roofs that must be ADA-compliant with slope up to 1:48, which equals 2.08% or 1.19 degrees. This is ¼ inch per 1 foot, which is the norm (minimum) roof slope for drainage.

The need for irrigation (beyond normal rainfall) will depend upon the plants selected, the local climate, and specific weather patterns, roof slope, and which LiveRoof system is selected.  In the north temperate zone (Standard system), supplemental irrigation may seldom be required. Even so, we suggest a backup irrigation system in the event of prolonged hot, dry, windy, sunny weather. During long bouts of dry weather, plants can shrink up, desiccate, die and expose soil. This can increase maintenance requirements as weeds can become established in bare soil and supplemental planting may be required. Excessively dry soil also causes the evaporative cooling effect of the green roof to stop.

Sprinkler irrigating a LiveRoof system.

Irrigating, even once per month during protracted dry weather, can keep your green roof looking its best and pay dividends through maintenance reductions and evaporative cooling. How frequently one must irrigate during protracted hot, dry weather will vary plant material, climate, exposure, wind, temperature, humidity and roof slope. Installing an appropriate irrigation system brings the peace of mind that when irrigation is needed, it can be applied quickly and conveniently.

Note: In areas of predictably hot and dry spring, summer and fall weather, one should always incorporate an irrigation system into the design. But, irrigation should not be used excessively – please consult your local LiveRoof grower for specifics.

A blue roof is designed to slow or store stormwater runoff, easing the burden on the stormwater systems.  When combined with the LiveRoof® brand green roof system—which in itself is an effective stormwater tool—the RoofBlue system maximizes rooftop stormwater management capability.  This may greatly reduce the need for other onsite stormwater management tools, such as cisterns, detention ponds, or underground storage tanks.

Retention means that a specific volume of water is retained on the roof for an indefinite period of time.  Detention means to temporarily detain stormwater before discharging it as runoff.

RoofBlue is intended for use as part of a water detention system, whose main function is to delay and control the flow of stormwater runoff.  This delay allows more time for municipalities to treat runoff, which helps to prevent stormwater and combined sewage systems from overflowing (untreated) into local waterways.

Control flow drains are designed to slow the rate of runoff from roofs during storm events.  These drains typically have an insert with a weir that regulates the flow of water through the drain.  They are available in a variety of heights.  Generally, flat roofs have lower weir heights than sloped roofs.  Some models have adjustable weirs which can be set for each drain / location, and some may utilize copper flanges to inhibit root growth.  All control flow drain systems should be carefully designed by a licensed professional engineer. These manufacturers sell controlled flow drains:

RoofBlue applications should be designed to hold no more than 3.5” of water beneath the green roof system.

Each inch of water weighs approximately 5.2 pounds per square foot, so at maximum water detention, the blue roof solution would add up to 18.2 pounds per square foot of load to the weight of the green roof modules (find saturated weights here).

In our experience, most roofing assemblies recommend that water does not stand for longer than 24 hours.

However, we recommend that architects and engineers confirm the maximum amount of time allowable for detention with the membrane manufacturer before specifying the type, size and placement of drains and pipes.

Most membrane manufacturers will have special requirements for blue roof applications.   In the early stages of blue roof design, is absolutely critical for engineers and specifiers to work with membrane manufacturers to select appropriate materials, thicknesses and to provide assembly instructions according to local code.

Also, confirm that the waterproofing specification complies with code.  Some municipalities have specific requirements for blue roof applications.  (Example: New York City stomwater construction guidelines address blue roofs).

INSTALLATION

Contact your LiveRoof local grower. See our grower network or call LiveRoof at 1-800-875-1392 or by email at sales@LiveRoof.com.

Colorful, completely-vegetated LiveRoof modules being placed on a roof.

Professional landscape and roofing contractors interested in offering LiveRoof installation services should contact their local representative for more information about opportunities to join our Certified Installer network.

We have developed an online training program for contractors working on their first LiveRoof project.  The course covers product, installation and initial maintenance specifications to equip estimators in preparing bids.  Prior to the first project installation, LiveRoof representatives conduct in-person training with the job site foreman and installation team.

Using a reciprocating saw to shape a LiveRoof module.

Yes, LiveRoof® modules can be cut to size and shape with the use of a masonry saw or reciprocating saw. When custom cutting LiveRoof® modules, the cut side should abut the non-cut side of another module, in order to contain the soil and minimize the work of installation.

If the cut side ever abuts edging, it should not be edging that is located on the low, draining side of the roof.  Always fit modules tightly against edging or parapet or surround with drainage fabric for added security.

MAINTENANCE

The life cycle of most weeds is about four weeks. Therefore, by weeding every 2 weeks, for just a few minutes, the few weeds that come from birds and the wind are not allowed to reproduce (and become many). This is the “smart” way to manage a LiveRoof, and it is what allows one to have a pristine LiveRoof with almost negligible maintenance costs.

Minimally and sparingly. One person can do this a couple times a week without causing permanent harm.  However, you must avoid walking in a single path, standing in one place, or trampling your plants.

If you must service a wall, parapet, or rooftop equipment, wait until the foliage is dry and conditions are not too sunny or hot.  Then, cover the plants with plywood or closed-cell foam for up to 4 hours.

Avoid repetitive foot traffic when plants are wet or frozen.

Whenever possible, avoid installing the green roof until all other trades have completed work on the skylights, parapets, HVAC or other rooftop equipment.  In our experience, the most common cause of plant losses are foot traffic from other trades performing work to equipment adjacent to the green roofs.

The need for irrigation (beyond normal rainfall) will depend upon the plants selected, the local climate, and specific weather patterns, roof slope, and which LiveRoof system is selected.  In the north temperate zone (Standard system), supplemental irrigation may seldom be required. Even so, we suggest a backup irrigation system in the event of prolonged hot, dry, windy, sunny weather. During long bouts of dry weather, plants can shrink up, desiccate, die and expose soil. This can increase maintenance requirements as weeds can become established in bare soil and supplemental planting may be required. Excessively dry soil also causes the evaporative cooling effect of the green roof to stop.

Sprinkler irrigating a LiveRoof system.

Irrigating, even once per month during protracted dry weather, can keep your green roof looking its best and pay dividends through maintenance reductions and evaporative cooling. How frequently one must irrigate during protracted hot, dry weather will vary plant material, climate, exposure, wind, temperature, humidity and roof slope. Installing an appropriate irrigation system brings the peace of mind that when irrigation is needed, it can be applied quickly and conveniently.

Note: In areas of predictably hot and dry spring, summer and fall weather, one should always incorporate an irrigation system into the design. But, irrigation should not be used excessively – please consult your local LiveRoof grower for specifics.

Yes, but likely not every year. The need to apply fertilizer will depend upon a number of factors, including plant type, climate, weather patterns, irrigation water, and more. Thus, LiveRoof recommends that each spring, before spring growth flush, a sample of green roof soil is sent in for testing to a lab qualified to test green roof soils (as compared to a typical field soil test).

If the Nitrogren (N) levels are low, the green roof will benefit from an application of controlled release fertilizer:

If Phosphorus (P) tests are low and the municipality allows for a fertilizer containing Phosphorus – we recommend Lesco 14-14-14. The application rate can vary based on need, and typically ranges from 1.5 to 3.0 pounds of actual Nitrogren (N) per 1000 square feet which is appx. 10 to 20 points of actual fertilizer per 1000 square feet. It comes in 40 pound bags, so a bag would cover 2000 to 4000 square feet of green roof.

If P tests are low and the municipality does not allow P in the fertilizer – we recommend Lesco 21-0-21. The application rate is typically 1.5 to 3.0 pounds of actual N per 1000 square feet, but in this case calculates to 7 to 14 pounds of actual fertilizer per 1000 square feet. It comes in 50 pound bags, so a bag would cover 3500 to 7000 square feet of green roof.

No, LiveRoof plants are damaged by de-icing chemicals. If your LiveRoof is adjoined by pedestrian walkways, you should use sand or cat-litter as an anti-slip measure after shoveling.

It is relatively easy to remove a LiveRoof module to access the roof deck.

  1. First, using a flat bladed shovel, probe the planting to locate the container edge.
  2. Then peel away some plant material. This is easy to do as the root systems of LiveRoof® plants is fibrous and easy to separate (not at all like sod).
  3. Using a sturdy pair of pliers, lift up and remove the exposed module.
  4. Any additional modules may be removed by trimming around them with the handle of a spoon and lifting them up.
  5. Once you are finished, replace the modules.

Important:  Never use sharp instruments around roof membranes.

Dog urine and excrement are toxic to (and will kill) succulent green roof plants. Therefore, unless you have a green roof that is specifically developed for dog traffic, dogs should be kept off of the green roof.

If your green roof has been specifically developed for dog traffic, then it is likely vegetated with either a turf grass or a lily-turf, such as Liriope NoMo® or Liriope spicata. Such roofs require a minimum of 6 inches of soil (the LiveRoof deep system), and should be cared for so as to preserve the plants material. Excrement should be picked up and the plants should be watered regularly, not just for hydration, but to flush the urine from the soil.

PLANTS & SOIL

In the Lite and Standard systems, we only recommend plants which have extreme drought resistance through some means other than the root system.  This means succulent, water-holding plants like Sedums, Alliums, Sempervivums, and Delospermas in the northern temperate regions, and similar species farther south.

The best LiveRoof plants will both store water and have a special type of metabolism called ‘Crassulacean Acid Metabolism’ (CAM). CAM plants are unique in that under drought conditions their stomates (leaf pores) are open at night rather than during the day, as is the case with most plants.  CAM plants exchange gasses (oxygen and carbon dioxide) in the dark when it is cooler and less windy.  CAM plants are up to ten times more efficient with water conservation than non-CAM plants.

In the Deep and Maxx systems, with irrigation, a broader plant palette is possible.

In all cases, consult with your local LiveRoof licensed representative for recommendations of the best plants for the climate.

Numerous vegetables, herbs, and select fruits (such as strawberries and melons) may be grown on intensive green roofs that receive frequent watering, have ample sunlight, and have proper soil.

Edible plants require sufficient nutrients to support their rapid growth cycle and the energy needed to bear fruit.

When growing produce on green roofs, a blend of organic soil and traditional green roof growing media yields the best results; however, the soil will need annual amendments to maintain volume and provide sufficient nutrition.

LiveRoof® brand engineered green soil is composed of approximately 94% high quality inorganic aggregates (by dry weight), contains a special clay particle to bind nutrients (in most regions), contains an acid rain buffering component (where appropriate), and is formulated with disease-suppressive organic material at a level that is consistent with ecologically sustainable soil/plant communities.

Our soil is designed to last indefinitely and to not substantially shrink over time. Cheap mixes with high levels of peat and compost will decompose and wash away as humic acid.

High quality, engineered green soil.

LiveRoof soils are formulated regionally by approved blenders.  These local adaptations of LiveRoof engineered soil will vary somewhat in composition based upon climate, water quality, and regionally available components.

Filter cloth, like any filter, is designed to filter. Over time, filters may plug up—think of your car’s air and oil filters, your furnace filter, coffee filter, etc. If green roof filter plugs up, then what?

Because of the aggregate nature of engineered soil, very little escapes through the LiveRoof module’s drain holes.  It’s like trying to push marbles through a funnel or a square peg through a round hold. In addition to this simple act of geometry, the roots of the plants bind the soil together and hold it in place.

PRODUCT FEATURES

With its unique patent pending Soil Elevators™ and Moisture Portals™, the LiveRoof® system gives you the look and function of a conventional green roof “membrane” system, with the turn-key benefits of a modular system. LiveRoof® represents the best aspects of modular and conventional green roofs combined in one simple, attractive effective system. LiveRoof® is an integrated system designed by growers in conjunction with experts in the fields of architecture, roofing, logistics, and ergonomics.  It is designed to grow plants! Composed of recycled plastic materials, LiveRoof® is based upon sound horticultural principles.  It is earth-friendly, as well as rooftop functional and aesthetically pleasing.  LiveRoof® systems, because they are pre-vegetated at the nursery, require minimal maintenance.  Compared to site-built green roofs, which are time-consuming and costly to install and maintain, LiveRoof® offers a turn-key alternative that doesn’t require you to be a horticulturist.  LiveRoof® modules can be vegetated with various plant assortments to address your particular design needs and climate.  And if there is ever any need to make changes to the roof, LiveRoof® modules are easily moved aside and replaced after the work is done.

The cost of any green roof is the sum of four costs:  acquisition, maturation, maintenance and lifecycle.  If one fixates on low aquisition cost, they are likely to get stuck paying for high maturation expenses, high ongoing maintenance costs (ongoing headaches) and a high lifecycle cost (with a system that is short lived).  With LiveRoof, that is not the case—we deliver quality, beauty and long term value.

LiveRoof is a value system It is not typically the “cheapest” system to acquire (nor is it the most expensive).  Compared to other options, it will likely cost a great deal less over time. Here is why LiveRoof is the best value:

  • LiveRoof is fully mature, there is no cost of maturation—that has been done at the nursery where it was fully grown, before it was ever delivered to the job site.  Plant-in-place systems may require 3,4 or more years of expensive (more than $1 per SF per year) of questionably effective rooftop cultivation.  Such systems are unlikely to ever become fully mature to the extent of LiveRoof, and most define success as 80% coverage after 3 years.  That means 20% of the roof will be “unvegetated,” and thus unsightly, a haven for weeds, prone to erosion and a drain on cash.

  • LiveRoof is uniquely easy and inexpensive to maintain—this is because of the unique plants that we select, breed, test and utilize.  LiveRoof has developed a unique plant palette designed specifically for rooftop applications.  These plants are tested to be hardy, dense-growing, and long-lived.  When maintained according to the LiveRoof standardized protocol, it is possible to care for an acre-sized LiveRoof (43,560 square feet) in as little as 15 hours per year.

  • LiveRoof is designed to last essentially forever.  The system itself is underground, and therefore protected from the elements, and therefore expected to last indefinitely.  And, the specially engineered soil is designed to maintain its physical characteristics indefinitely.  It will probably outlast many other aspects of the building, and can even be moved and reused, if that ever became desireable.

  • LiveRoof is amazingly beautiful.  There is far to little attention paid to the aesthetic and social value of the green roof.  In fact, there are those that try to dumb down the emphasis on beauty, and attempt to commoditize green roofs as they would rubber membrane or gravel.  Reference to the plant material as an “assortment of Sedums” is about as sensible as referring to carpeting as an assortment of fibers.  You wouldn’t buy just any old carpeting or shingle, you would match it to the color scheme and design vision of your building.  The same ought to be true of your green roof system and your plant selections—for the same reasons: design, quality, maintenance, lifecycle and value.

  • LiveRoof growers have access to a unique palette of RoofTop Proven™ plants that can yield amazing colors, textures and beauty to optimize the aesthetic quality of your project while minimizing maintenance. Beauty yields intrinsic value—that can equate to monetary value.  Consider this; beautiful vistas yield happy customers, tenants and employees, and that equates to monetary value through loyalty, productivity and efficiency.

Horticultural experts avoid standing water. That’s because standing water is deprived of oxygen, and roots sitting in oxygen-deprived water become diseased with fungal and bacterial rot. This weakens the plant, and may perpetually handicap the plant and predispose it to secondary disease and insect infestation.

After considering pros and cons of powder coating versus anodizing, we chose to anodize RoofEdge.  Powder-coated finishes offer flexibility in color options; however, the durability of the finish can vary greatly.  With some products, we observed loss of paint in as little as two years.

As green roofs are intended to last decades, we need a finish that would last as long.  As anodization is a change to the chemical composition of the aluminum component’s surface, it becomes a permanent feature.  This finish is most suitable for salty environments (such as near ocean spray) and its hardness allows the finish to endure more abuse than a coated product.

  • RoofBlue raises the modules an additional 3.5” from the roof surface.  The riser void space is approximately 90.5%.
  • At 3.5”maximum water depth, RoofBlue provides up to 455 cubic inches (approximately 2 gallons or 7.4 litres) of water detention per square foot.
  • The control flow roof drain insert should be even to the lowest point of the green roof installation, the water will not exceed 3.5” in height.  This ensures that the plant roots are kept out of standing water.
A diagram showing the maximum water height in RoofBlue risers.

The RoofBlue riser is compatible with all LiveRoof module sizes.  The riser will raise the green roof system by an additional 3.5”, which means that taller aluminum edge restraints are required to surround the entire blue / green roof assembly.

Edging Recommendations

  • RoofBlue with the LiveRoof Lite (2.5”) system: Use RoofEdge Deep (6.5″ tall)

  • RoofBlue with the LiveRoof Standard (4.25”) system: Use RoofEdge Maxx (8.5″ tall)

  • RoofBlue with the LiveRoof Deep (6″) or Maxx (8″) systems: Specify an edge restraint of approximately 10.5″ for Deep/RoofBlue or 12.5″ Maxx/RoofBlue (typically custom fabricated).  Alternatively, it may be more economical to use one or more rows of LiveRoof Standard (4.25”) vegetated roof modules at the perimeter and transition to the LiveRoof Deep (6”) or Maxx (8”) systems in the field of the installation.  The modules are designed to integrate between these sizes without edging.