Two installers laying down vegetated mat on rock mineral underlayers on highrise flat rooftop.

Engineering Vegetated Roofing Systems to Optimize Stormwater Management

The StormCap™  green roof system  is complete vegetated roofing system. Quality pre-grown mats, engineered growing medium and high performing base layers help achieve long lasting results.Three dimensional image of layers that create the StormCap green roof system

Premium Components:  Enhanced by Urbanscape urbanscape-logo-by-knaufinsulation

Engineered base layers include Urbanscape’s Needled Mineral Hydro Blanket. VFormaldehyde-free, this innovative virgin rock product uses no chemical binders.  The Needled Mineral Hydro Blanket offers an environmental alternative to the other mineral wools on the market and has a superior performance of 90% of water retention by volume.  As a result, it is ideal for vegetated roofs acting as a water reservoir and supporting plant health. Hence, it can supplement or in some cases replace heavy growing media. For these reasons it is an exceptional rooftop stormwater management tool throughout the lifespan of the vegetated roof.

StormCap™ Key Features:

  • Pre-grown, instant “green” with 85% foliar coverage upon installation
  • Stormwater retention 2.6″ (1.6 gal/ft2)
  • Saturated weight 28 lb/ft2
  • Most of StormCap™’s base layers come in rolls for ease of transport and installation

Fully CustomizableImage of biopocket sedum and custom planting options.

The  StormCap™   is a fully customizable system with biodiversity options such as the BioPocket™. There are two BioPocketTM styles: a combination of sedums and perennials or color-blocked sedums-only.  The former requires a deeper depth of growing medium.

A detail rendering of the biopocket inserted in the StormCap vegetated system to create greater biodiversity.

Detail rendering of the BioPocket integrated into the StormCap vegetated system to add biodiversity and greater visual and topographic interest.

Contact us for an estimate or consultation on your roofing project.

Industry leading in performance and engineering

With deep roots in vegetated roofing, Stormwater Capture Co is committed to delivering breakthrough products and services that help with stormwater management solutions.

Stormwater Capture Co offers a single source solution for a complete green roof system package.  We customize your system to local requirements and provide warranty and support.  We are a one-stop-shop supplying vegetated mats, high performing base layers, pavers and accessories.

Rodney Chaney

Rodney Chaney, Technical Sales Manager, Stormwater Capture Co

Sluiceway Interactive Exhibit

Join Rodney Chaney for the hands-on Green Roof Sluiceway on Monday February 11, 2019.  It will take place 12:30-1PM in the Exhibit Hall at the New Jersey Chapter ASLA Annual Meeting at Harrah’s Waterfront, Atlantic City. Be sure to also stop by and visit us at Booth #73.

The workshop will explain the role innovative green roof technology plays in retaining and detaining rainfall and how green roof systems attenuate stormwater and reduce the environmental footprint.

Several Ways Green Roofs Reduce Environmental Footprint

Vegetated roofing systems reduce the environmental footprint in many ways, simultaneously.

For instance:
• Water: The green roof helps detain and retain rainfall at its source and therefore control runoff.

• Energy saving: Through shading, insulation and evaporative cooling the green roof therefore helps reduce energy use.

• Climate: Green roof reduces flash floods and combined sewage overflow. It addition, it mitigates the urban heat island effect.

Stormwater is the main way pollution gets into the rivers and waterways

A good rainfall really cleans the city streets.  All the road salt, cigarette butts, animal feces, antifreeze, dust, automotive rubber and metal — all is swept up in the rain, into the storm sewers and therefore into our waterways.

The Exibitor Lab workshop will illustrate this with an interactive demonstration of the how green roof systems help retain and detain rainfall. Following this, Rodney will present a 7-10 minute technical Power Point describing the green roof system’s benefits, with a focus on its capability to attenuate and retain stormwater and mitigate urban heat island.

Sluiceway interactive exhibit will be presented at the New Jersey Chapter ASLA Annual Meeting Exhibitor Lab Monday February 11, 2019.

How Green Roofs Help

The Workshop will ask two volunteers to pour gallons of water onto two sloping platforms.  Platform One will mimic a typical roof and feature a waterproofing membrane. Trash and that would be found on city walk and road ways and end up in the sewer system. Platform two features the StormCap pre-vegetated system that collects rainfall and helps with stormwater management.  At the end of each platform a 7-10 gallon storage bin will collect the “rainfall” and trash.  The audience will witness the performance of the StormCap vegetated roofing system and learn why vegetative roofing technology plays a key role in stormwater management.

Image depicts a lightweight green roof that captures rainfall and cools the roof compared to the grey roof to the right.

Image to the left depicts green roof benefits of protecting and cooling a building and capturing stormwater at the source.

Register and Visit Us

Register here for the 2019 NJASLA Annual Meeting.  Please visit us and Rodney Chaney at Stormwater Capture Co Booth #73.

Stormwater Capture Co offers a single source solution for a complete green roof system package . We customize your system to local requirements and provide warranty and support.  We are a one-stop-shop supplying vegetated mats, high performing base layers, pavers and accessories.

Green infrastructure offers climate resilience in urban environments.

Green Roofs Mitigate Urban Heat Island Effect

Acacia Smith explains the Albedo Effect. And, how your roof can help fight climate change.

The majority of the roofs in the world are dark-coloured and as a result have a low albedo and absorp excessive amounts of heat.

The majority of the roofs in the world are dark-coloured and as a result have a low albedo and absorp excessive amounts of heat. The ‘albedo’ of a surface is its ability to reflect solar waves; dark surfaces reflect very little whereas light surfaces such as ice have a high albedo and reflective ability. When sunlight hits a white surface, it bounces back and passes through the atmosphere. But once it is absorbed through a dark surface, sun is transformed into heat, which when reflected back during the night cannot pass back through the atmosphere and so remains in circulation.

Urban Heat Island Effect

The low albedo of cities is a problem felt in many urban areas and contributes to the ‘urban heat island effect’ causing deadly heat waves in cities.

The most recognisable outcome of the low albedo of cities is a problem felt in many urban areas throughout the world; the ‘urban heat island effect’ (UHIE). As naturally climate regulating vegetation is removed in favour of infrastructure, cities become pockets of higher temperatures. The difference between heat absorbing urban areas and their surrounding hinterland can be up to 5° degrees. The layers of smog that smother many cities today and the carry on health effects that are increasingly prevalent, are a result of UHIE.


Green Roofs Cool the Atmosphere & The Building

Image depicts a lightweight green roof that captures rainfall and cools the roof compared to the grey roof to the right.

One way to increase the albedo of a roof is to plant vegetation. Rooftop gardens, and green roof systems such as the StormCap, create a buffer preventing heat from entering the building. They have a positive impact on temperature both within the building and outside as well as improving air quality. Green roofs may be one of the only ways possible to reduce UHIE and to adjust the urban fabric of our cities to cope with increasing temperatures and fight against climate change . By regulating temperature variability, green roofs also reduce energy consumption. They provide added insulation in the colder months and prevent excessive heat absorption in the summer.

Vegetated roof reduces the heat flux through the roof.

Vegetated or green roof systems reduce the heat flux through the roof.

Green roofs are gaining popularity rapidly. Several cities are beginning to encourage green roofs through legislature and tax incentives. New York is offering tax rebates to people wishing to install green roofs. Tokyo has a new policy that requires 20% of new government buildings and 10% of private buildings to have green roofs.


“It just doesn’t make sense to leave thatspace unused when we could transform our energy future and reduce urban heat island effects with all the options.” Laurel J. Standley, Ph.D.  ~  Scientist, Author


Acacia Smith wrote the above for the Sustainable Business Toolkit which offers strategies, tactics and tools to help small business grow and propser.  To learn more about what they do click here.


13 Sep 2018

Experienced Green Roof Expert Joins Team

Stormwater Capture Co is proud to announce and welcome Rodney Chaney. Rodney is the new Technical Sales Manager and the company’s first point of contact for green roof inquiries. He will help deliver full life cycle vegetated roof solutions to clients across the North Eastern and Mid-Atlantic US.

“We are very excited that Rodney has joined our team and convinced that he will add another layer of success to our efforts in delivering much needed stormwater solutions,“ said Richard Aronson, General Manager. “Rodney comes to us with a wealth of experience, knowledge. He is respected throughout the industry for his honesty, integrity and accomplishments. He shares our vision, passion and above all, our commitment to satisfying our clients’ needs.”

Upon earning his Bachelor’s degree from St. Mary’s College of Maryland, Chaney embarked on a career in the construction industry with a focus on sustainable building systems.

Finding Real World Sustainable Solutions

“Finding real world, economic, sustainable solutions with a dedicated team of owner’s, roofers, GCs, engineers, architects drives my interest,” said Chaney.  “I was drawn to the opportunity with Stormwater Capture Co. because of the team approach with other partners to research, design, and apply common sense solutions for increasing storm water concerns.”

During his successful 10 year career, Chaney has gained vast experience at several companies that serve the roofing and vegetated roofing industries.   Chaney has been involved in estimating and delivering full life cycle new construction, retrofit, and rehabilitation green roof solution on over a half million square feet of structures.

“I’ve seen the growing environmental impact made by our built environment. This has led me to focus on sustainable low impact development as a career where I work closely with contractors, engineering firms and owners to incorporate green roof systems to ensure project success. I look forward to continuing this tradition as I begin this new chapter,” Chaney said.

Chaney’s notable green roof projects include:

  • Montgomery County Multi-Agency Service Park
  • McCormick Spice Headquarters
  • MLK Memorial Library

Meet Rodney and the rest of the team at CitiesAlive 2018, September 24-28, 2018 Brooklyn, NY. Alternatively, you may contact Rodney at 855.786.7626 ext 6,

About Stormwater Capture Co

Whether it’s a leading edge award-winning design or best value-for-money, the Stormwater Capture Co™ team delivers breakthrough vegetated roofing systems that help achieve results. The “go-to-single-source-solution” for the complete system package.





16 Jul 2018
Living Roof - Camden

Johnson & Johnson World Headquarters, New Brunswick, NJ

Stormwater Capture Co is featured in WATERPROOF! a quarterly magazine that is a great information resource for all types of waterproofers, including residential and commercial waterproofers, foundation contractors, and thousands of large roofing contractors.  The magazine reaches 10,000s interested readers throughout the U.S. every quarter.  Download the article: Waterproofing-Green-Roofs, Waterproof Mag, Summer 2018


About Stormwater Capture Co

Our team prides itself in being a hassle-free, one-stop-shop supplying vegetated systems that can be customized to local requirements, with warranty and maintenance support. We also offer ​access to a variety of analytical support service​s such as ​stormwater calculations specific to location ​and building/roof type.

We specialize in supplying green roof systems with​ high water retention-to weight ratio such as the StormCap system. Our premium base layers ​include​ the ​Needled ​M​ineral ​H​ydro ​B​lanket and can be easily cut to fit any shape and design.​ Contact us 855-786-7626 or send drawings to get an estimate for your project.


Copyright © 2018 Stormwater Capture Co. LLC. All rights reserved.



Dedicated to sustainability, NYC Convention Center embodies world-class technological innovation

NYC Convention Center green roof brings nature back to urban core.

The 6.75-acre green roof on the Javits Convention Center makes the 27-year-old building an example of sustainable retrofitting – attracting many species of birds, bats, bees and even tourists who go on rooftop tours.  This NYC landmark is also closely monitored by a team of engineers from Drexel University and The Cooper Union for the Advancement of Science and Art who have designed and installed sensor systems to track its environmental impact.

CEO very pleased with performance of vegetated roof

In a recent interview with NPR (see video below), Javits’ CEO Alan Steel explained the significant aesthetic, environmental and economic benefits of the green roof.

Honey harvested in Fall of 2017 from NYC’s rooftop.

“Besides the great reaction, there are practical benefits.  We have three hundred thousand bees, we’ve seen 25 different species of birds on the roof. We reduced the temperature out here by about six degrees Fahrenheit and we also save about seven million gallons of stormwater runoff that’s absorbed in the  soil and the plants.  We’ve been able to reduce our energy consumption by about twenty six percent and that translated for us last year (2016) into a saving of about three million dollars.”  Javits is now also selling honey harvested from the rooftop.

“The success of our sustainability program epitomizes our rebirth as an organization, and this first batch of honey illustrates how far we have come in our efforts to reduce energy, create a wildlife haven and improve the quality of life in our neighborhood,” said President and CEO Alan Steel.

Green roofs are a learning laboratory for Engineers

Professor Franco Montalto in the department of Civil, Architectural and Environmental Engineering at Drexel College is the lead researcher on the Javits green roof project. He says in recent years the City of New York has made major commitments to sustainability and green infrastructure.

“The Javits Center green roof exemplifies the kind of environmentally sensible urban redevelopment projects that the City wants to encourage. The retrofit building will reduce urban runoff, mitigate the urban heat island effect, and, potentially have a cooling effect on the streets and buildings that surround it. Our research will seek to quantify these benefits,” said Montalto.

Watch NPR feature on Javits

Montalto’s research team is currently also monitoring more than 15 other green infrastructure sites in New York, New Jersey, and Pennsylvania. Students from The Cooper Union will monitor the data and use it to learn about and model functional sustainable design projects.

“The Javits Center green roof project provides Cooper Union students with a significant learning opportunity to study sustainable design and use New York City as a learning laboratory,” said Dr. Joseph Cataldo, a professor in the Albert Nerken School of Engineering at The Cooper Union.  “Our students are presently developing a model to predict the thermal behavior of the green roof using climate and infrared data. This information will be helpful to better gauge hydrology and temperature variations of the green roof, which, subsequently, is an important part of determining and understanding temperature patterns in green roofs and New York City as a whole.”

“Water and energy are intimately linked through the process of evapotranspiration,” Montalto said. “Incident solar radiation changes liquid water, originally deposited on the roof by precipitation, into water vapor which then leaves the roof surface. The energy consumed by this process keeps the roof and building cooler than it otherwise would be, since without the green roof this energy would simply heat up the roof surface. At the same time, if the air in the vicinity of the air conditioner intake pipes is cooler, these units have to work less to cool the -already cooler- building.”

For more on the Drexel and Cooper Union green roof research, click here.

About Stormwater Capture Co – Supplier of High Performing Vegetated Roofs

Stormwater Capture Co supplies green roof systems with high water retention to weight ratio, ideal for retrofits and new builds.

Our team prides itself in being a hassle-free, one-stop-shop supplying vegetated systems that can be customized to local requirements, with warranty and maintenance support. We also offer ​access to a variety of analytical support service​s such as ​stormwater calculations specific to location ​and building/roof type.

Stormwater Capture Co supplies a range of systems from lightweight to biodiverse.  Premium base layers ​include​ the ​Needled ​M​ineral ​H​ydro ​B​lanket.  Sedum blanket and base layers can be easily cut to fit any shape and design.​

Contact us 855-786-7626 or send drawings to get an estimate for your project.

Copyright © 2018 Stormwater Capture Co. LLC. All rights reserved.

StormCap pre vegetated roof system

The StormCap vegetated roof system above uses Needled Mineral Hydro Blanket and retains 2.6 inches of rainfall. Photo: Greg Van Riel


Vegetated roofing has long been recognized as an effective stormwater management tool in urban centres to help store and attenuate runoff from impervious rooftops. New technological advancements are helping further increase stormwater retention capacity on rooftops while keeping weight low.

One such significant advancement is the use of rock mineral wool (RMW)—which offers both advantages—in place of a greater depth of traditional growing medium. There are several varieties of mineral wool on the market, produced for different applications.



When it comes to stormwater retention and vegetated roof survivability, not all mineral wools are created equal.


Mineral wool is a general term for a light, artificial wool made of an inorganic substance such as glass, stone, or slag. It was originally invented in the mid-19th century for thermal and acoustic insulation in the construction industry.

Almost 50 years ago, a modified form of RMW in the form of slabs, blocks, and bonded fibres started being used as a substrate in hydroponics in Denmark. (For more, read the 2002 article, “Substrates and their Analysis” by M. Raviv et al., published in D. Savvas and H. Passam’s Hydroponic Production of Vegetables and Ornamentals by Embryo Publications in Greece.) Today, it is present in virtually all advanced horticultural markets, and is used for growing hydroponic fruits, vegetables, herbs, and flowers.

RMW for vegetated roofing applications is manufactured by a fiberization process induced by heating a mixture of various rock components (usually diabase, dolomite, granite, basalt, etc.), which are melted together at high temperatures. (Further information on mineral wool production can be found in B. Širok et al.’s 2008 publication Mineral Wool Production and Properties from England’s Woodhead Publishing Limited.) The melt is spun into thin fibres on fast-rotating machines and is later bound for dimensional stability.

Generally, there are two major differences between methods of making the loose, melted rock fibres dimensionally stable and transforming them into slabs, blocks, or wool. They can be bound using a chemical-free needling process to physically interconnect loose fibres, or those loose mineral wool fibres can be glued with binders. Examples of the latter option include:
• sodium silicates;
• polyesters;
• melamine urea formaldehyde;
• polyamides;
• resin-based phenolic; or
• furane-based resins. (From Kowatsch’s article, “Mineral Wool Insulation Binders,” published in Phenolic Resins: A Century in Progress from 2010.)


Advancements have been made in the manufacture of mineral wool over the decades, offering environmental alternatives and products with superior performance. One development has been the use of formaldehyde-free binders, which rely on renewable resources. This new generation of mineral wool is an environmentally responsible alternative to phenol-based products. It uses renewable resources for binding agents and has enhanced water absorption characteristics. The most notable development is the production of the needled rock mineral wool, the Needled Mineral Hydro Blanket, Hydro Cubes and Hydro Flocks, manufactured without additives or binders.


The high water retention of needled or binderless mineral wool (Hydro Blanket above, Hydro Cubes and Flocks) reduces the need for irrigation and improves plant survivability. Photos: Knauf Insulation

hydro cubes

Hydro Cubes and Flocks are designed to be mixed with traditional growing media to increase rainwater holding capacity.


Flocks and Cubes are recommended for containers, patios, and ground level landscaping and contribute to better soil structure, water-holding capacity, and aeration of growing media.











It is important to understand how this engineered product supports long-term stability and stormwater retention performance in outdoor applications such as vegetated roofing. Needled rock mineral wool can be ideal for vegetated roofs, as it acts as a water reservoir and supports plant health, replaces heavy growing media, and performs exceptionally as a rooftop stormwater management tool throughout the lifespan of the vegetated roof.

Categories of rock mineral wool

Installation of Needled Mineral Hydro Blanket on Camden, NJ school rooftop.

Various types of RMW are currently available, each complete with its own unique advantages, drawbacks, and properties.

They are those that use 1) traditional chemical binders, 2) bio-based binders, and 3) needled or binderless RMW. The latter is the most recent innovation in RMW. Below are details why binderless RMW is ideal for vegetated roofs.

1) Traditional binders

The most common mineral wool on the market is sprayed or bound with phenolic resin or diluted phenol-formaldehyde (PF) for dimensional stability. These binders also help make the product water-repellent. This type of mineral wool is typically used as insulation in the construction industry. When traditional mineral wool is modified with a hydrophilic (or wetting) agent, it can be used as a growing media for hydroponic cultivation in a strictly controlled environment. If this type of mineral wool is used as an alternative to other growing media, it requires uniform conditions such as a greenhouse where usage cycles tend to be relatively short (i.e. from one growing season to five, in the case of ornamental plants). If it is exposed to any varying, uncontrolled climatic conditions (e.g. dry/wet periods, freeze/thaw cycles, or high/low temperatures) for longer periods, its water-holding characteristics will change significantly, resulting in decreased hydrophilic ability. In other words, cycles of drought or precipitation will negatively influence the material’s long-term performance and its water absorption capacity. This phenomenon likely occurs due to the hydrophilic agent rinsing out, which causes the initial hydrophobic character to prevail. Therefore, traditional mineral wool is not ideal for outdoor applications such as vegetated roofing. Its hydrophobic propensity renders it an inconsistent and unreliable stormwater management product over time, unable to effectively sustain rooftop plants under significant stress in hot and dry seasons.

2) Formaldehyde-free binders

A new generation of mineral wool providing a solid alternative to the traditional variety has been invented and commercialized in the last decade. Bound together using a bio-based technology, this mineral wool is free from formaldehyde, phenols, and acrylics and uses no additional artificial colours, bleaches, or dyes. This reduces harmful manufacturing emissions and workplace exposures, improving the overall sustainability of buildings into which the product is incorporated.

However, as with traditional mineral wool, bio-based binders will typically render the mineral fibres hydrophobic. A hydrophilic agent must be added to improve the hydrophilic capacity of the material. While mineral wool with bio-based binders will retain more water than phenol-based mineral wool, its long-term water absorption capacity decreases, as it does with the phenol-based variety, due to the flushing of the hydrophilic agent during periods of drought and precipitation.

3) Needled or binderless innovation

Fig 1. Needled rock mineral wool without binders—virgin material (SEM analysis, zoom 1000x).

The most recent advancement in this industry is the manufacture of needled rock mineral wool—a non-petroleum-based and formaldehyde-free alternative. Products made this way are known as Needled Mineral Hydro Blanket, Cubes or Flocks. The needling process provides dimensional stability without the use of any binders—mineral wool is formed by a mechanical interconnection of pure mineral fibres. This process forms a structurally stable, lightweight, and porous material with longer fibres (Figure 1) that can maintain excellent water-holding properties. It is consistently hydrophilic, even after varying weather cycles throughout the year. The material can hold 90 per cent of its volume in water. When wet, the majority of the retained water is easily available for plants’ uptake. (This was tested by pH curve. The authors can provide data upon request.) A minimum of 10 per cent oxygen is left in the needled mineral wool, enough to support the oxygen levels in the root zone and, therefore, healthy roots. The material is inert, with chemically stable fibres. On the left side of Figure 1, the condition of fibres three years after installation is shown with soil particles attached.




Fig 2. Needled rock mineral wool after three years of installation (SEM analysis 800x). Photos courtesy Institute Jožef Štefan

The hydrophilic characteristics of the Needled Mineral Hydro Blanket can offer long-term stability, as nothing rinses away. The physical attraction between fibres and water remains the same throughout the lifetime of the product.  Binderless mineral wool offers hydrophilic characteristics that better support root growth and overall plant health, making particularly suitable for many vegetated roof applications, with long-term survivability in various climatic zones.







Needled or Binderless Mineral Wool is Ideal for Vegetated Roofs

Needled mineral hydro blanket absorbs stormwater and feeds plants for improved survivability. It also reduces the need for irrigation

• It is lightweight;
• It can supplement or, in some cases, replace heavy growing media;
• It can act as a water reservoir while supporting plant health;
• It achieves more credits under the Leadership in Energy and Environmental Design (LEED) program (The material contributes to eight additional points under LEED v4. These include credits in the Sustainable Sites [Protect or Restore Habitat, Open Space, Rainwater Management, and Heat Island Reduction], Energy and Atmosphere [Optimize Energy Performance], Materials and Resources [Environmental Product Declarations], and Indoor Environmental Quality [Thermal Comfort and Acoustic Performance] categories.); and
• It performs exceptionally and reliably as a rooftop stormwater management tool throughout the lifespan of the vegetated roof (as seen on Sweden’s Karolinska University Hospital, Rentenversicherung headquarters in Berlin, and various projects throughout Baltic and Scandinavian countries).

Needled Mineral Hydro Blanket comes in a roll and has a density of 286 to 319 lb/35 cf. It is also available as Hydro Cubes (0.8 x 0.8 in) and Hydro Flocks (0.1 to 0.8 in.) and is recommended for containers, patios, terraces and ground level landscaping applications. Cubes and flocks are added to a traditional growing medium and contribute to better soil structure, water-holding capacity, and aeration. The retained rainwater inside the Hydro Cubes or Hydro Flocks is easily available for plant uptake and improves plant survivability.

Research and analyses

As the needled manufacturing process does not require binders, it ensures the product’s natural hydrophilicity remains intact, making it highly reliable for long-term stormwater management performance in vegetated roofs (Figure 2).When it comes to long-term water absorption, research shows needled mineral wool (Hydro Blanket, Cubes and Flocks) designed for growing plants outperforms traditional horticultural RMW by up to three times. Water uptake (WOK) analysis is used to determine this. This method shows the velocity of water absorption in time for specific substrates. After saturating and drying out, the capacity of absorption is measured for 1500 minutes. The results show long-term water absorption of needled mineral wool for growing plants is 70 per cent, whereas traditional phenol-based horticultural mineral wool absorbs significantly less—between 20 and 35 per cent. (Water uptake analysis test method developed by Regeling HandelsPotgronden [RHP], Netherlands.)


Fig 4. Stormwater testing lab in Virginia.

As experience and numerous studies show, RMWs using binders are commonly recognized as products for hydroponic growing, and the needled or binderless type—due to its unique characteristics—is ideal for outdoor environments. For example, it can be used in vegetated roofs for significant improvement of stormwater performance and roof longevity in different climate zones. Research indicates RMW positively influences plant growth and development on vegetated roofs as well as in other applications. (From D. Majkovič et al.’s 2016 presentation, “Promote Vegetated Roof Stormwater Performance with Mineral Wool Layer,” from Cities Alive in Washington D.C. Also from C. Arkar et al’s 2015 publication, “Lightweight Green Roofs’ Thermal Response Under Freezing Conditions,” from Energy Procedia 78.) It also showed great potential in container substrates as an alternative growing medium in the 1990s. (The study that determined this can be found in W.C. Fonteno and P.V. Nelson’s Physical Properties of and Plant Responses to Rockwool-amended Media, published in 1990 by the Journal of the American Society for Horticultural Science.) Applications of the new generation of Needled Mineral Hydro Blanket confirms this finding. (See A. Šušek et al’s presentation from Ramiran 2015 at the Hamburg University of Technology, “The Impact of Rock Mineral Wool on Water Retention in a Conventional Growth Medium, and Development of Zonal Pelargoniums.”)

Fig 5

Vegetated roofs constructed with binder-free needled mineral wool are tested and have been applied in various climate zones from moderate to extreme. Going forward, the focus continues to be on stormwater performance in retention testing, where vegetated roofs with a needled mineral wool layer are compared to traditional, engineered-growing-media-based vegetated roofs. One stormwater testing laboratory in Virginia (Figure 4) uses custom technology to apply replicable computerized rain events mimicking real-life rain events to evaluate assemblies 80 sf in size. In Figure 5, the quantity of water retention and transient water is shown as measured on those samples in 90 minutes. Full and dotted blue lines represent the values for a vegetated roof with a binder-free needled mineral wool layer, which is nearly doubled in stormwater performance compared to a 4-in. vegetated roof with traditional engineered growing media only (shown with grey full and dotted lines in Figure 5). The mineral wool layer does not significantly affect the dynamics of the release, but strongly influences the quantity.

Fig 6

The second graph (Figure 6) indicates stormwater performance is equivalent between a 101-mm vegetated roof with a needled mineral wool layer to which 72 gal is applied after 90 minutes (again, shown with blue full and dotted lines) and a 8-in. vegetated roof without a mineral wool layer (with 68 gal applied after 90 minutes). Introducing the needled mineral wool layer on the roof leads to significant load savings and the possibility of applying this solution when retrofitting. (Mineral wool weighs approximately 10 times less than the same amount of soil.)


Technological developments in needled or binderless mineral wool over the last decade have focused on increasing water retention and maintaining long-term performance. Needled mineral wool’s characteristics better support root growth and overall plant health in various climatic zones, from hot and arid to frigid and wet, whether used in indoor applications such as urban farming or outdoor applications such as landscaping or vegetated roofing. Having been used in Europe for the past decade—with the largest projects being in Scandinavia, the Baltic States, and Germany—needled mineral wool has recently become available in North America, providing American designers and engineers a viable solution to landscaping in arid areas and increasing the stormwater management capacity on rooftops where this would otherwise be impossible.



A performance evaluation tool developed in collaboration with the Laboratory for Sustainable Technologies in Buildings, University of Ljubljana, helps assess the real performance of a defined roofing system in any city in the world or in different climate zones. A software package was created from its results
Photo courtesy Knauf Insulation

To help design/construction professionals more effectively create vegetated roofs, various manufacturers are introducing new tools and software to the industry. In collaboration with the Faculty of Mechanical Engineering’s Laboratory for Sustainable Technologies in Buildings at the University of Ljubljana, Slovenia, one company has developed a performance evaluation tool as a result of a two-year in-situ performance study of different types of vegetated roof systems. This tool helps assess the real performance of a defined roofing system in any city in the world or in different climate zones.

The University of Ljubljana test and evaluation has been ongoing since 2014, and the initial two-year results have been used to create a software package intended to help current and potential users and owners of extensive vegetated roofs understand the real performance they can expect. As well as vegetated roofs’ stormwater performance, this software provides data on how such roofs can improve buildings’ energy performance and how they can reduce heat island effect.

Darja Majkovič is the head of products and applications in green solutions at Knauf Insulation. For nearly a decade, Majkovič was a researcher at the University of Maribor, focusing on agricultural economics and econometrics. Her work includes collaboration on numerous national and international research and development projects. Majkovič was a visiting researcher at the French National Institute for Agricultural Research (INRA) and a university lecturer, and has written more than 160 articles. 

Jure Šumi is the business development director at Knauf Insulation, leading several teams. These include “Urban Green Infrastructure,” which focuses on developing lightweight green roof systems for stormwater management, “Landscaping and Gardening,” which focuses on developing substrates and systems for water conservation in arid climates, and “Horticulture,” which focuses on developing environmentally responsible hydroponic alternatives. Šumi has more than 20 years of experience in business and market development for multinational companies in a variety of sectors. 

Cristina Senjug serves as the communications manager at Stormwater Capture Co.  

Stormwater Capture Co prides itself in being a hassle-free, one-stop-shop supplying vegetated systems that can be customized to local requirements, with warranty and maintenance support. We also offer ​access to a variety of analytical support service​s such as ​stormwater calculations specific to location ​and building/roof type.

We specialize in supplying green roof systems with​ high water retention-to weight ratio such as the StormCap system. Our premium base layers ​include​ the ​Needled ​M​ineral ​H​ydro ​B​lanket and can be easily cut to fit any shape and design.​

Contact us 855-786-7626 or send drawings to get an estimate for your project.

Copyright © 2017 Stormwater Capture Co. LLC. All rights reserved.