07 Nov 2017

High above ground level, invisible to many of us, green roofs are present in almost all climate zones mimicking nature, helping clean the air, cooling down temperatures, and keeping rainfall on-site, alleviating pressure on urban stormwater systems.

Green roofs, also known as vegetated roofs, are classified as either intensive or extensive.

Intensive roofs feature a variety of plants in a heavy and deep substrate layer of 10 inches or more.

Intensive green roofs may incorporate many sizes and types of plants found on ground level including shrubs and trees,

can include planters, benches and fountains, and are usually used as a rooftop amenity space.

Extensive roofs are lighter in weight due to shallower substrate (1-6 inches) and typically feature vigorous, low-growing, drought tolerant plant species such as sedums and mosses. Extensive green roofs are an economical stormwater management solution, easier to install, remove and repair, require less maintenance than intensive systems, and may be retrofitted on many existing buildings.

High performing extensive system.

Green roofs, whether intensive or extensive, experience the same cycles of growth, flowering and dormancy that occur to plants on the ground level.  Vegetated roofs that are properly designed for climates with four seasons, correctly installed and routinely maintained, have a greater probability of survival no matter the season.

Best autumn and winter practices for extensive vegetated roofs

Extensive vegetated roofs are a prevalent green infrastructure technology throughout North America, yet many questions arise as to their aesthetics, performance and survivability in winter climates.  Some people question whether green roofs die in the winter or whether snow damages the vegetation.

Others want to know whether the roof can be walked on in winter months or if vegetation needs to be re-seeded in the spring.


Extensive systems predominantly use hardy sedum species that can withstand harsh rooftop conditions year-round. Sedum are drought tolerant and thrive in harsh conditions.  The best suited rooftop plants are pre-grown outdoors locally, for several months or a year ensuring they are acclimatized to the local climatic conditions.  Ensuring that the vegetation is mature upon installation offers a higher probability of survival.  In colder plant hardiness zones or in areas where there are extreme fluctuations in temperature, green roofs require a deeper depth of engineered growing medium to help mitigate the effects of intense temperature and moisture changes.

Additional growing medium acts as a thermal mass helping moderate the temperature and further hydrating the plants – helping reduce significant die-back in the winter or during hot summer droughts.


In Autumn, as winter approaches, green roofs enter the dormancy cycle. As rooftop conditions are harsher than at the ground level, the exposed vegetation on rooftops enter into the dormancy cycle earlier than at ground level.

Dormancy is a natural reaction to adverse environmental conditions. It can happen in the summer during periods of intense heat and drought, or in the fall in preparation for the coming cold winter months.

During dormancy, plants simply stop further growth and development to conserve energy. Dormancy is a plant’s defence mechanism to keep itself alive. The retreating plants are not dead.

Dormancy synchronizes with the environment and can be triggered by a temperature drop or sudden changes in climactic conditions, such as reduction in rainfall and water shortages. Green roofs lose their flowers and change colour creating a beautiful landscape of reds, bronze and browns, to deep purples.

During winter dormancy, coniferus sedum plants retreat to form a dense mat of glossy and fleshy leaves, while the leaves of deciduous sedum species completely fall off.


Many vegetated roofs are installed in the Autumn due to the construction schedule and desire to finish the project. In such cases, it is critical to have mature and well established plants as they have greater survivability on rooftops than plants that are immature seedlings.Pre-cultivated systems should have a minimum of 80% coverage upon installation to ensure there is blanket coverage and minimum erosion of growing medium. The pre-cultivated vegetation may have been disturbed during harvest, transport and installation.  Therefore, after installation, it is imperative to keep the vegetated system hydrated during the establishment period for the plants to recover and take root and prepare for the coming winter.


Once cold temperatures set in, the vegetated roof will go into dormancy and prepare for winter. The blanket of pre-cultivated vegetation shelters the growing medium from erosion from the strong, cold winds. Snow accumulation is ideal as it insulates the vegetation.  A blanket of snow shelters the vegetated roof from strong winds and helps the plants retain moisture. If there is little or no snow accumulation, and the vegetated roof is subject to high winds, extreme fluctuations in temperature or a particularly severe ice storm, plant desiccation, or “winter burn” can occur. Desiccation a type of injury where the plant dries out and dies. This may expose areas of growing medium that may be subjected to erosion by high winds. If such damage occurs to the vegetated roof, a straightforward procedure for repair can be followed the following spring. This repair procedure also applies to other vegetated roof repairs due to excessive foot traffic or due to construction materials left on the plants forextended periods of time.

The repair is done in the spring using a variety of sedum clippings sprinkled, where needed, to replace the sections that have been damaged or eroded.  Succulent plants such as sedums are easy to propagate. Many can be rooted from a single leaf, others will root quickly from a stem cutting.For areas that suffered erosion, additional engineered growing medium should be added, as required. After the initial planting of clippings, frequent, light irrigation is required to keep the vegetated roof moist and help ensure the plants take root.


Year-round maintenance is key to ensuring long-term survivability as well as the stormwater performance of the vegetated roofs.  One last maintenance check should be done in the autumn as part of the yearly routine.  Vegetated roofs are also known for their ability to protect the roof membrane, however, not taking proper preventative measures can also lead to unforeseen problems.

Autumn maintenance includes the removal of debris and inspection of all drainage paths.

In Autumn, it is best to remove fallen leaves and twigs from the green roof. Thick layers of leaves and twigs can also stick together to form an impenetrable mat and may lock in too much moisture, potentially causing rot or damage to the plants.

nlWeed, one last time, before winter sets in. In an effort weed control, make every effort to capture the seed pod intact and tuck it away for disposal to avoid seeds blowing away.  Some weeds may be tolerated, therefore maintenance personnel should be familiar with green roof plants and the owner’s green roof aesthetic preference.

Keeping the vegetated roof hydrated into the Autumn months helps the vegetationavoid winter’s freeze-drying effect caused by low temperatures and high winds.

If there is an irrigation system, it needs to be winterized around October in nothern States as frost typically sets in soon after. Maintenance crews typically use an air compressor to blow out the water from the irrigation system.

On ground level, perennials tend to be cut back. On the rooftop, however, tall grasses or wildflowers are ideally cut back the following spring. This encourages re-seeding and the stalks give winter protection to bees and other fauna. Snow-covered stalks also offer a pleasing visual aesthetic.

Vegetated roofs should not be fertilized past August, especially with a slow release type fertilizer. Fertilization may stimulate tender growth and compromise the hardiness of the plant. Secondly, plants won’t have a chance to fully take up the nutrients and the combination of high temperatures may cause the plants to burn. Slow release fertilizer is usually applied once, ideally in the spring.

Assess the performance of the green roof in the autumn and prepare for next spring.  It is a good idea to document  your visit with photos and record recent weather conditions for future reference and any potential warranty claims.

In cold climates, particularly when temperatures drop below freezing, foot traffic over vegetation must be avoided as it can prove lethal, leaving foot-shaped patches of dead plants. The damage will be obvious the following spring and recovery may take several months or may not happen at all.If pedestrian traffic is unavoidable, protective measures must be taken to diminish the impact of damage.  Materials like plywood sheets or insulation boards may be laid over the vegetation temporarily to help distribute the weight on the green roof, and removed at the end of each day to allow plants to recover.

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

Numerous municipalities have vegetated roof programs, incentives or requirements with a focus on stormwater management. Here are examples of a policies and incentives that are promoting the growth of the vegetated roofing industry.

RainScapes Rewards Rebates Program in Montgomery, MD offers qualified residential and commercial vegetated roofs tax rebate of $10/sf.

Baltimore Stormwater Fee Credit offers rebates for reducing impervious surface.

Blue Water Baltimore Green Roof Incentive offers $2/sf and covers up to 50% of total cost of project.

Green Roof Permit Program in Chicago, IL allows for density bonus and accelerated building permit.

Green Roof Tax Credit Philadelphia, PA, provides businesses a rebate of 50% for project cost up to $100,000.

Stormwater Management Incentives Program (SMIP) and the Greened Acre Retrofit Program (GARP) Philadelphia, PA offer stormwater management grants to non-residential property owners, and contractors.

Onondaga County’s Green Improvement Fund (GIF) Syracuse, NY has provided nearly $9 million in funding to local green infrastructure projects on private property

Green Infrastructure Grant program in NYC offers a grant program for private property owners in combined sewer areas of New York City. The minimum requirement is to manage 1″ of stormwater runoff from the contributing impervious area.

Green Roof Tax Abatement Program, New York, NY, offers rebate of $4.50/sf up to $100,000 per project.

Green Roof Rebate Program in Washington, DC: provides base funding of $10/sf, and up to $15/sf in targeted sub-watersheds.

RiverSmart in Washington DC provides reduction in stormwater fees and property taxes.

Green Infrastructure Partnership Program in Milwaukee, WI offers $5/sf for approved vegetated roofs.

Stormwater Credit Program in Minneapolis, MN includes vegetated roofs for stormwater utility discount of up to 100%.

Green Roof Credit Program in Nashville, TN offers up to $10/sf of green roof installed.
Stormwater Management Credit for Green Roofs in Devens, MA vegetated roofs may reduce size of stormwater management systems, save land and money.

Clean River Rewards Incentive and Discount (CRID) Program in Portland, OR provides property owners with the opportunity to earn a discount on their monthly stormwater utility charge by treating stormwater runoff onsite. Discounts are available to property owners based on the extent and effectiveness of on-site stormwater management practices that control flow rate, pollution, and disposal.

Density Bonus Incentive in Seattle, WA allows downtown commercial, residential, and mixed-use developments which gain LEED Silver or higher certification to build to a greater height and/or floor area than would normally be permitted.

Green Factor Program in Seattle, WA requires 30 percent of a parcel in the Neighborhood Commercial Zone to be either vegetated or functionally equivalent to a vegetated area.

Downtown Density Bonus Program, Austin, TX allows buildings with vegetated roof greater floor area than would normally be permitted.

Green Roof Loan Program in Cincinnati, OH offers $5 million in low-interest loans to property owners – residential, commercial, or industrial— for the design and construction of green roofs with an option to incorporate on-ground stormwater controls.

Stormwater Management Tax Credit in Anne Arundel County, MD offers 10% of the cost of the material and installation of an approved stormwater management practice, limited to $10,000.00.

Green Roof Rebate in Palo Alto, CA provides $1.50 per square foot for the installation of a vegetated roof to a maximum of $1,000 per single-family residential property and $10,000 for commercial/industrial and multi-family residential properties.

The Green Building Ordinance in San Francisco, CA sets standards for stormwater runoff and allows for expedited permits for green buildings.

Contact us for more info.

11 Sep 2017
Green infrastructure offers climate resilience in urban environments.

How vegetated roofs alleviate impact of climate change

Vegetated roofs, otherwise known as green roofs, are a key part of infrastructure resilience in an era of extreme heat events and more frequent and intense downpours.

Below are 4 ways vegetated roofs can have an immediate impact to improve resilience:


1. Help manage localized flooding

Vegetated roofs absorb rainfall, and help prevent water from overwhelming stormwater sewers and flooding streets or basements.  This reduces damage to infrastructure and property. They also reduce the volume of stormwater that flows into streams and rivers and thus protect local watersheds.


Vegetated roofs help mitigate urban heat island effect cooling the building, surrounding air and improving human health and comfort.

Vegetated roofs help mitigate urban heat island effect cooling the building, surrounding air and improving human health and comfort.

2. Help reduce urban heat island 

Vegetated roofs are a natural cover for rooftops that would otherwise absorb and retain heat.  Vegetated roofs mitigates air pollution levels an remove heat from the air through evapotranspiration. On hot days, vegetated roofs, reduce temperatures of the roof surface, and the surrounding air, improving human health and comfort.



Vegetated roof reduces the heat flux through the roof.

Vegetated roof reduces the heat flux through the roof.

3. Help lower building energy demands 

By shading the surface of the building, the vegetated roof is reducing the heat flux through the roof and reducing the indoor temperatures and demands on air conditioning.





Vegetated roofs delay peak flow and reduce pumping and treatment demands for municipalities.

Vegetated roofs delay peak flow and reduce pumping and treatment demands for municipalities.

4. Help save money managing water

Vegetated roofs retain and detain rainwater, delaying peak flow into sewer systems which helps reduce pumping and treatment demands for municipalities.


15 Aug 2017
Birds eye view of the vegetated roof on Mastery Cramer Hill Elementary.
Architectural rendering of Cramer Hill Elementary School in Camden, New Jersey designed by Blackney Hayes Architects.

Mastery’s first newly constructed school, Cramer Hill Elementary utilizes the latest approaches in construction technology.

CAMDEN, NEW JERSEY, UNITED STATES — The start of the new school year will be a fresh start, in more ways than one, for the Camden community that the new Mastery Cramer Hill Elementary school will serve.

“This brand new, safe and beautiful facility is one step in the right direction offering a world class education to Camden kids,” says Joseph Ferguson, Chief Operations Officer, Mastery Charter.

“That first day of school, what will really matter to me is that students and parents take pride in the school that was designed and built with them in mind. I want them to take ownership and truly believe this is a place where they can learn, and grow.”

World Class Education for Camden Kids

The city of Camden suffers extremes of poverty, and is reported to have among the nation’s highest violent crime rates. Many kids are in schools that are historically lower performing – in the bottom 10 per cent statewide – some in classrooms with no windows and no natural light.

Happy second-graders at one of Mastery's 24 schools in Philadelphia and Camden.

So impressed with their approach to education, talk show host Oprah Winfrey generously donated $1 million to the Mastery Charter organization.

Come September that will change for up to 750 local students who will attend the new school on East State and River Streets. Ferguson says that when students arrive at their new school, he wants them to “experience joy and great instruction.”

Cutting Edge Approach to Education and Technology

The vegetated roof, a high performing StormCap™ system, will be part of the learning as it is visible from classrooms on two levels. “In the construction of this new facility, the green roof presented a very economical and environmentally friendly stormwater solution,” says Ferguson. “It also provides an educational opportunity. Our teachers are excited and are looking forward to program the space in the future. We want students to be able to appreciate it. We want it to be part of the science program, by explaining why we have it, how it works, and how it helps the environment.”

Panorama photo of the construction of the Mastery Cramer Hill Elementary School vegetated roof.

Architects Kevin Blackney and Troy Hill of Blackney Hayes Architects designed the building. They say the green roof was proposed early in the design process to help with storm water management, and also as a learning tool. “This is Mastery’s first newly constructed school and in keeping with their cutting edge approach to education and technology, they thought it was important to utilize the latest approaches in construction technology,” said Troy Hill. “The green roof technology also gives the teachers the opportunity to use its function and maintenance to supplement their curriculum.”

The vegetated roof and pervious parking reduce runoff and manage stormwater on-site helping keep the local waterways clean. “Like most projects in urban environments with aging infrastructure, the storm sewer in the area is “combined” with the sanitary sewer flows,” explained engineer Charles Chelotti. “During heavy rainfall events, this combined system discharges directly to the local waterways and rivers. For this specific project, although there was net reduction in impervious coverage from the pre-existing condition, it was still necessary to reduce the impact to the “combined” system in the area, some of which may be over 100 years old.”

In addition to superior stormwater management, the vegetated roof offers other benefits for the building and the environment such as cooling the building, prolonging the lifespan of the roof itself, providing natural habitat and reducing the urban heat island effect. Also, research shows that biophilic design has direct advantages to students and teachers as views of natural landscapes from classrooms benefit academic achievement and behavior.

Workers unroll the sedum blanket onto the growing medium.

A team of workers from Ganter Contractors install the nearly 3000 square feet of vegetated roof in less than one day.

Ferguson, who is overseeing the construction of Mastery’s brand new building, is excited, too.

In mid-July under the blazing sun, Ferguson was present to watch workers from Ganter Contractors install the nearly 3000 square feet of vegetated roof in less than one day. “It looked very organized and straightforward. The team knew exactly what they were doing and I was very impressed with how efficient the installation happened.”

With school just around the corner, the team continues to work hard on the finishing touches to welcome new, eager students who will learn to love to learn.

About Mastery Charter Cramer Hill 
Mastery Charter operates 24 schools in the cities of Philadelphia and Camden. Cramer Hill Elementary is their first newly constructed school and will welcome up to 750 students and their families from kindergarten through 8th grade. From music to art to field trips – students will get a well-rounded education. Mastery schools are a special place where children experience the joy of learning in a safe, positive environment with a focus on 5 core values: respect, responsibility, hard work, teamwork and kindness.

StormCap pre vegetated roof systemAbout the Vegetated Roof System 
Innovative and easy to install, this green roof system is enhanced by the Urbanscape® Needled Hydro Mineral Blanket to maximize stormwater retention and keep weight down. The vegetated roof system uses pre-grown mats, engineered growing medium and high performing base layers loosely laid on a Sika Sarnafil roofing membrane making a more reliable roof.

StormCap™ vegetated system has superior water retention properties.
This green roof is customizable and contributes to 8 additional LEED points in the following credit categories:
• SS – Site Development Protect or Restore Habitat; Open Space; Rainwater Management; and, Heat Island Reduction
• EA – Optimize Energy Performance
• MR – Environmental Production Declarations
• EQ – Thermal Comfort; Acoustic Performance

22 Mar 2017

Launching advanced solutions:  Innovative rooftop technology for Designers, Landscape Architects, Engineers and Building Owners


NEW YORK, USA, March 21, 2017 /EINPresswire.com/ — In recent years, flooding has occurred more frequently affecting a broader range of communities than ever before. Dense urban development, aging sewer systems and increasingly extreme weather are some of the main causes – calling for increased on-site stormwater management. The Stormwater Capture Co™ crew is on top of it with rooftop solutions to reduce the impact of major rain events on your building, your city and neighboring watersheds.

With deep roots in vegetated roofing, the Stormwater Capture Co™ team delivers breakthrough products that will help achieve results. The goal is simple: To be the “go-to-single-source-solution” for the complete system package, to certify and train qualified installers and to demystify green roofing for owners and designers alike.

“Whether it’s a second level rooftop garden, a 10th floor amenity space, or a non-accessible rooftop on the 25th story, there is a vegetated roof solution for almost every building. Our team simplifies the task of choosing the right vegetated roof for your building,” said Richard Aronson, General Manager at Stormwater Capture Co. “With a wealth of experience in our field, our team provides specialized technical and design consulting, as well as a high level of customer support whether it’s for bid package preparation or on-going maintenance. We pride ourselves as being a one-stop shop where you get everything you need in a greenroof, and nothing you don’t.”
Capture Rainwater On Site: Start With Your Roof

One of the products offered is the StormCap™ system, a high performing, easy to install green roof enhanced by Urbanscape®’s needled mineral hydro blanket. Manufactured by Knauf Insulation, the hydro blanket offers superior water retention making it ideal for vegetated roofs, as it is lightweight, can supplement or, in some cases, replace heavy growing media and can act as a water reservoir and support plant health.

During a major rain event, the StormCap™ system will retain 2.6″ of rainfall or 1.6 gallons per square foot. StormCap™ is also easy to cut and fully customizable.

With premium base layers, the StormCap™ system contributes to 8 additional LEED points in the following credit categories:

• SS – Site Development Protect or Restore Habitat; Open Space; Rainwater Management; and, Heat Island Reduction
• EA – Optimize Energy Performance
• MR – Environmental Production Declarations
• EQ – Thermal Comfort; Acoustic Performance


Custom Feature: Biodiversity

A perfect addition to the StormCap™ vegetated roof is the BioPocket™, a custom feature that provides an island of biodiversity and enhanced aesthetics where you want it. Working like a butterfly or bee island, the BioPocket™ is used to create a berm, or knoll, on your green roof to provide habitat and food for pollinators. The BioPocket™ brings a burst of color, perennials or grasses and is placed on various depths of growing media, depending on the building load capacity and your design goals.

A perfect addition to the StormCap vegetated roof is the BioPocket™, a custom feature that provides an island of biodiversity and enhanced aesthetics where you want it.

Control runoff under patios, walkways and fire-free zones

Walkways can also be designed to help absorb rainwater using the innovative SpongePaver™ System which incorporates the needled mineral hydro blanket with a drainage mat under a traditional paver. This offers a unique solution to control stormwater runoff on the rooftop.

The SpongePaver™ System incorporates the needled mineral hydro blanket with a drainage mat under a traditional paver to help control runoff under rooftop patios, walkways and fire-free zones.

Stormwater Capture Co serves the Great Lakes region and the rest of the north eastern United States, helps meet your goals whether the roof is a leading edge award-winning design or best value-for-money. Come meet us at the North/East Roofing Contractor’s Association (NERCA) Annual Convention and Trade Show, March 28-31, 2017 in Atlantic City, N.J. where samples of the StormCap™ system and the BioPocket™, among other products, will be shown.

01 Feb 2017

The most notable development to date in vegetated roofing is the production of the needled mineral hydro blanket – a non-petroleum and formaldehyde-free alternative.

Knauf’s innovative needling manufacturing process provides dimensional stability without use of chemical binders.  The needled hydro blanket is formed by mechanical interconnection of pure mineral fibers.Needled Mineral Hydro Blanket

This process forms a structurally stable, lightweight and porous material with longer fibers that maintains excellent water holding properties. It is consistently hydrophilic, even after various weather cycles throughout the year. Up to 90% of the material retains rainwater. When wet, the majority of the retained water is easily available for the plants uptake.

The water absorption characteristics are not affected over time as nothing rinses away and will remain the same throughout the lifetime of the products.

The Needled Mineral Hydro Blanket is ideal for vegetated roofs, as it:

  • can supplement, or in some cases replace, heavy growing media
  • can act as a water reservoir and support plant health
  • achieves greater LEED credits
  • performs exceptionally and reliably as a rooftop stormwater management tool over the lifespan of the vegetated roof

Needled Mineral Hydro Cubes and Hydro Flocks

hydro cubesThe above needled, binderless, mineral wool also comes in the form of small hydro cubes (about 0.7 cubed) or hydro flocks (0.1-0.7 inch pieces) to mix with traditional growing media.

This is an innovative method of  improveing traditional growing media. Cubes and flocks contribute to better soil structure, water holding capacity and aeration of growing media. The retained rainwater inside the hydro cubes or hydro flocks is easily available for plant uptake, improving plant survivability. Cubes and flocks are specially recommended for patios, terraces and home gardening.


24 Jan 2017

Everything you need in a green roof: And, nothing you don’t. 

The StormCap™  is a complete vegetated roofing system using quality pre-grown mats, engineered growing medium and high performing base layers.

StormCap pre vegetated roof system

Superior Components:  Enhanced by  urbanscape-logo-by-knaufinsulation

The engineered base layers include Urbanscape’s needled mineral hydro blanket, made solely of virgin rock fiber. This mineral wool has no binders and therefore has superior retention of 90% of water by volume and withstands freeze/thaw cycles.

Most of StormCap’s base layers come in rolls that are easy to transport and install. It is a fully customizable system with biodiversity options using the BioPocket™.
BioPocket options









Industry leading in performance and engineering

With deep roots in innovative vegetated roofing solutions, Stormwater Capture Co is committed to delivering breakthrough products and services that will help achieve much needed stormwater solutions.

01 Dec 2016

Many remember the Eastern United States flooding of June 2006, a widespread flood that affected numerous watersheds and communities from North Carolina to upstate New York, causing millions of dollars in damages and taking 16 lives.

In the Federal Triangle, two metro stations were flooded and several federal buildings such as the National Archives, the Internal Revenue Service, the Department of Justice and several Smithsonian museums were forced to temporarily close.


In response to severe weather events such as the 2006 flood, District Department of Energy and Environment (DOEE) prepared and recently released the Climate Ready DC Plan which identifies 77 actions to reduce risks to infrastructure and its citizens. Among other things, the plan aims to make “100% of District waterways fishable and swimmable by 2032″. No small feat.

One goal is to “Relieve pressure on stormwater infrastructure and reduce long-term flood risk” with a target of capturing 75% of rainwater on-site for filtration or reuse. The first on its action list for stormwater management is the creation of two million additional square feet of green roofs by 2032. Such actions will “help prevent runoff from ruining river water quality and destroying plant and animal habitats”.

Mayor Vincent Gray’s ambitious vision is for Washington to become the” healthiest, greenest, and most livable city in the United States”. In achieving these goals, Washington “will be a model of innovative policies and practices that improve quality of life and economic opportunity”.

It is am important and grand plan. Let’s not only wish them luck but let’s work together to make it happen.

Photos credits: Sierra Club