FREQUENTLY ASKED QUESTIONS

What’s so special about the LiveRoof® system?

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.

Why Do I need a Southeast Specific Green Roof Expert

The climate in the Southeast is predictable - hot and humid. Standard, run of the mill green roof plant performance in the Southeast is not predictable. At James Greenroofs, we have dedicated years of research into finding the plants most well adapted to our harsh environment. We’ve reached outside of the typical succulent based plant mixes, incorporating species native to the southeast region along with cutting edge breeding to provide a mix of plant species that will outlast and outperform anything the competition provides. However, our southeast green roof expertise does not stop at our plant knowledge. We provide everything from in person design consultation to on-site installation certification. Our group of local, certified installers ensure a team of well trained professionals will provide outstanding workmanship to complete your LiveRoof project.

Does my green roof need irrigation in the Southeast?

A vegetated roof top in Southeast will need supplemental irrigation during periods of extended drought.  We recommend using overhead pop up sprinklers along with PipeRunner for a low cost, efficient, and reliable green roof irrigation system.  A cistern on site will provide a sustainable resource for irrigating your green roof.  Weather sensors can be incorporated in the irrigation system to protect against over or under watering.  

Requirements for irrigation amounts will vary depending on the location and environmental considerations specific to the vegetated roof.  A fully vegetated roof in Atlanta, Georgia will experience temperatures well in excess of 100 degrees F in the summer.  An extensive vegetated roof with 4-6" of soil and a custom, drought tolerant plant mix will require full soil saturation every 7-10 days during the summer months.  

 

What rebate programs are currently available for green roofs in the Southeast?

A green roof rebate is currently available in Metro Nashville for private properties within the combined sewer system area. Metro Water Services offers a maximum total credit in the amount of $10 per square foot of green roof installed. The private properties sewer charges will be credited for 60 months or until the maximum total is reached. Per the Metro Water Service green roof credit requirements, the vegetated roof portion must cover at least 50% of the roof space and must reduce total runoff volume (Runoff Volume Reduction) by 60%.

Energy savings – what can I expect?

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. Plants transform heat and soil moisture into humidity, to create natural evaporative cooling. Each gallon of water that is transpired by the plants or evaporated from the roof surface liberates 8000 BTU of thermal energy.

Why doesn’t the LiveRoof® system use filter cloth? And, won’t the soil run out the drain slots?

Filter cloth, like any filter, is designed to filter. Filters in time can plug up (think of your car’s air and oil filters, your furnace filter, coffee filter, etc.). When a green roof filter plugs up, then what? Hint… bathtub (ok for water lilies, but not ok for green roof plants).

Because of the aggregate nature of LiveRoof® soil, the soil stays in the LiveRoof® module as it would if you poured it into a funnel. It’s like the square peg in a round hole scenario. In addition to this simple act of physics, the roots of your LiveRoof® plants bind the soil together and hold it in place.

Why doesn’t the LiveRoof® container have moisture reservoirs?

Because it was designed by horticulturists. Horticulturists know that moisture reservoirs store water. Stored water is oxygen deprived, and roots sitting in oxygen deprived water become diseased with fungal and bacterial rot. This weakens the plant, may spread to the crown of the plant, and may perpetually handicap the plant and predispose it to secondary disease and insect infestation.

What is so special about LiveRoof® soil?

Unlike cheap soils that are marketed as light weight, and packed with peat moss and perlite, LiveRoof® soil is predominately composed of high quality inorganic aggregates, contains a special clay particle to bind nutrients, contains an acid rain buffering component, and is formulated with disease suppressive organic material at a level that is consistent with ecologically sustainable soil/plant communities. LiveRoof® 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. Perlite after several freeze thaw cycles may shatter repeatedly and turn to dust. It may also float to the soil surface after heavy rains, then blow away when conditions are dry and windy.

Note: regional adapatations of LiveRoof® engineered soil will vary somewhat in composition. Each is specifically developed based upon climate, water quality, and regionally available components.

How much does the LiveRoof® system weigh?

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.

Can I retrofit my existing building?

It depends on the load capacity of the existing building. Also, some older buildings can be redesigned for the additional weight of the LiveRoof® modules. A qualified engineer must always conduct a thorough analysis.

What are the best plants to use with the LiveRoof® System?

Those that have extreme drought resistance through some means other than the root system. This means succulent, water-holding plants like Sedums, Alliums, Sempervivums, Delospermas and a few others. The best LiveRoof® plants will both store water and have a special type of metabolism called ‘Crassulacean Acid Metabolism’, CAM for short. CAM plants are unique in that under drought conditions their stomates (leaf pores) are open at night rather then 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.

LiveRoof® plants have been selected for extreme drought tolerance, disease and insect resistance, long life, low maintenance, and beauty. LiveRoof® plants are planted in the LiveRoof® modules at Hortech and other nurseries and cared for until shipped to the job site. Plants are selected by local horticulturists in order to meet the above objectives as well as the local climate and customer preferences.

Can I grow edibles with the LiveRoof® System?

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.

What is the urban heat island effect?

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, 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 within the city, with drought, high winds and electrical storms being more common than surrounding rural areas.

How does the LiveRoof® system help mitigate the urban heat island effect?

Traditional rooftops are usually covered with tar, 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, a process known as evapotranspiration, and act like evaporative cooling systems to make the air surrounding them 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.

How does the LiveRoof® system reduce storm water 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. In some cases, it may cause overflows of sanitary sewer systems, causing the dumping of untreated sewage. In contrast, LiveRoof® green roof surfaces can absorb up to 99% of a 1” rainfall, reduce runoff, lessen the risk of 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 media is filtered and delayed until after peak flows, which allows additional time for sanitary sewer systems to handle uncontrolled runoff.

How does the LiveRoof® system reduce noise?

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.

Where can the LiveRoof® system be used?

LiveRoof® works well on low-sloped (non-pitched) roofs, on industrial, commercial, institutional, governmental and residential buildings. LiveRoof® works on any building where the building is appropriately engineered and the owners are progressive-minded and value the many economic, environmental, and health benefits that come from vegetated roofs.

Can the LiveRoof® system be used in nonroof areas?

Certainly—median strips, patios, plazas, and malls are also great opportunities to use the LiveRoof® system.

Can I lift up a LiveRoof® module if I want to access my roof?

Yes, it’s relatively easy. First, using a flat bladed shovel, probe the planting to locate the container edge. 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). Using a sturdy pair of pliers, lift up and remove the exposed module. Any additional modules may be removed by trimming around them with the handle of a spoon and lifting them up. Once you are finished, replace the modules. Note: Never use sharp intruments around roof membranes.

Can LiveRoof® modules be cut to fit odd dimensions and angles?

Yes, LiveRoof® modules can be cut to size and shape, either while pre-vegetated or empty with the use of a radial arm saw (with masonry blade) 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.

Can I walk upon my LiveRoof® plants?

Yes, you can do this a couple times a week without causing permanent harm. If you want to pamper your plantings and avoid foot prints, make yourself a small pair of “snowshoes” out of plywood. Make them about 8 x 14 inches and attach some elastic cord to strap them to your feet. This will spread out your weight and protect your plants. Note: Be careful walking in such “shoes”, it will be a bit awkward and you don’t want to fall off of the roof. Always follow OSHA guidelines: “tether” yourself when working near the roof edge.

How do I go about having a LiveRoof® system installed?

Call us today. Our team would love to hear from you.