Understanding Green Roofs and Their Benefits: A Comprehensive Guide

In the modern era, green initiatives are becoming increasingly popular as we strive to combat climate change and promote sustainability. One such initiative is the implementation of green roofs.

What is a Green Roof?

A green roof, also known as a living roof, is a roof of a building that is partially or completely covered with vegetation and a growing medium, planted over a waterproofing membrane. It may also include additional layers such as a root barrier and drainage and irrigation systems.

Note: Green roofs are typically installed atop flat or slightly sloped roofs.

In essence, a green roof is an outdoor garden space located on the top of a structure, featuring sedum or other succulents grown into low-level substrates.

Types of Green Roofs

Extensive Green Roofs

Extensive green roofs are lightweight and low-maintenance. They are often used on residential, commercial, and city buildings as they can be installed on a variety of structures. The sedum plants used are easy to manage and require minimal watering, making them ideal for areas that are difficult to access and maintain.

Modular Green Roofs

An innovative approach to green roofing is the modular green roof. This is a pre-grown roof that is developed in specially designed cassettes at a farm. These cassettes can be hand-carried and clicked together to form a seamless green roof.

The advantage of a modular green roof is that it provides an immediate green roof, reducing the time and disruption caused by traditional green roof installations. It also allows for easy access to the deck as they can be lifted into place and easily removed if necessary.

Advantages of Green Roofs

Green roofs offer a myriad of benefits:

  1. Aesthetically Pleasing: They improve the look of buildings, providing a natural, calming environment in urban settings.
  2. Temperature Regulation: They act as natural insulators, reducing the need for artificial cooling and heating.
  3. Biodiversity: They create habitats for wildlife, promoting biodiversity.
  4. Stormwater Management: They absorb rainwater, reducing runoff and mitigating flooding.
  5. Air Quality: They filter pollutants and carbon dioxide out of the air, improving air quality.
  6. Noise Reduction: They can help to reduce ambient noise.

Cost of Green Roofs

The cost of implementing a green roof varies depending on the type of green roof and the specific requirements of the project. For instance, the cost of an M-Trayยฎ, a type of modular green roof, is approximately ยฃ88 per square metre.

Please note, prices are subject to change.

Components of a Green Roof

A green roof typically consists of several components:

  1. Vegetation: The vegetation on a green roof is usually a mix of different types of sedum species. There may also be a mix of wildflowers and sedum available upon request.
  2. Substrate: This is the growing medium for the plants. It’s specially mixed to provide optimum drainage.
  3. Filter Membrane: This prevents the substrate from being washed away with the drainage water.
  4. Drainage Layer: This ensures that excess water is removed from the roof.
  5. Root Barrier: This prevents roots from penetrating the waterproof membrane.
  6. Waterproofing Membrane: This is an essential component that protects the building from water seepage.

Maintenance of Green Roofs

Despite their many benefits, green roofs do require maintenance. The sedum on green roofs is very hardy and can tolerate extreme conditions. However, watering during extreme conditions is advisable. Regular removal of dead leaves and vegetation is also recommended.

In addition, the application of a slow-release fertiliser at certain times of the year can promote plant health and growth.Additional Considerations

Before installing a green roof, there are several considerations to be aware of:

  1. Load Capacity: The weight of the green roof must be considered. Consult an engineer to advise on loadings.
  2. Light Requirements: While the plants on a green roof can tolerate partial shade, they do require some light to grow.
  3. Fire Regulations: A hard border between vegetation and the walls of buildings is required by fire regulations.
  4. Delivery and Installation: The green roof modules are delivered stacked onto pallets and must be unpacked within 24 hours of delivery. A crane and forklift may be needed to transfer pallets onto the roof.

Green roofs offer a unique combination of environmental benefits and aesthetic appeal. They represent a significant step towards more sustainable and environmentally-friendly urban environments. Whether you’re considering a green roof for your home or business, this guide provides a comprehensive overview of what you need to know.

Exadeck fire rated porcelain decking system

Brompton Road, Knightsbridge: May 2023

About the project:
A penthouse terrace required a Class A fire-rated decking system.

An existing timber deck mounted onto timber bearers had been strippedโ€ฆ.

โ€ฆ..out to reveal an unusual roof deck which had multiple levels and a series of upstands which appeared to be column supports from the structural walls beneath.

A secure substructure frame had to be constructed using Wallbarn MetalPad D adjustable height pedestals fitted to a selection of Wallbarn aluminium rails/joists. Both the Box Rails and the I-Plus beams were used due to the many varied height thresholds across the area.

At points the height thresholds were very tight, so the lowest height pedestals were fitted to 20mm Box Rails whilst in other areas, the 100mm high I-Plus Beam was double up and fitted to itself. These were then mounted onto much larger MetalPad D pedestals in order to create a consistent level to fit the deckboards.

The laying pattern of the Exadeck porcelain deckboards was to be on a diagonal plane to the building so the top layer of aluminium rails needed to be fixed on this angle to allow the decking fixing clips to be mounted at right angles to the rails.

Connector brackets were used where rails met each other for structural strength and stability to the substructure.

The Exadeck porcelain decking board is manufactured with a side milling profile. Hidden wing clips are fitted into the side profiles to securely hold the boards in place and provide a consistent gap between the boards for drainage.

This gives a tidy and consistent gap between boards. It is important to remember that Exadeck porcelain boards are rectified as part of the manufacturing process. This means dead straight lines are assured across the area and there is no risk that the boards themselves curl or alter in thickness or width.

We overcame challenging detailing because cutting a material with such consistency allows us to achieve sharp, clean lines effortlessly.

The various different parts of the duplex terrace was decked out with a clean, modern and consistent finishโ€ฆ

โ€ฆproducing a stunning, sturdy, natural looking decked terrace fully compliant with the highest fire regulations.

The Importance of Proactive Green Roof Maintenance

Fertiliser added to a green roof

Maintenance. Youโ€™ll hear a lot of talk about this when designing and planning for a green roof installation. How often? What does it entail? How expensive is it? Is it necessary?

Some clients, specifically those who are mainly interested in undergoing the project to meet their municipalityโ€™s stormwater retention requirements, think they can skip out on investing in a professional green roof maintenance contract, and go with a cheaper, less qualified landscaper to do the work instead. Or, even worse, they donโ€™t sign on with anyone at all to do maintenance. These clients often end up calling back after a few years because the plants are not doing very well on their roof. 

Proper maintenance is critical to the long-term survival of the plants and the likelihood they will thrive. Healthy plants contribute to more stormwater retention, more evapotranspiration, support biodiversity and look great. Green roof maintenance has nuances that a traditional, ground-level, landscaper could easily overlook without prior experience with rooftop greenery. This skillful practice is not a one-size-fits-all type of deal; maintenance regimes will look different for intensive green roofs, sedum extensive roofs, pollinator meadows, and rooftop farms. Implementing spring maintenance of a green roof is especially critical to ensure a prosperous growing season.

Beyond the different types of green roofs, your spring maintenance regime will look slightly different based on your respective climate zone. For example, a green roof in a tropical climate like Singapore will have a much different plant palette than one installed in Denver, Colorado. A big goal of the roof in Denver is to retain as much moisture as possible to withstand the summer heat and possible drought. A core challenge of a green roof in Singapore is ensuring proper drainage so the plants donโ€™t drown from excessive rainfall. In essence, a significant difference in climate will translate to differences in the kind of maintenance conducted. This is due largely to the difference in plants chosen based on the desired functions of the system. However, the main pillars of spring maintenance remain more or less the same, no matter the type of system or geographic location. 

Soil/Growing Medium Health

As a green roof owner or maintainer, youโ€™ll want to pay close attention to nutrient levels in the soil/growing medium to ensure it is healthy and able to foster optimal, long-term plant growth. Once there is no longer a concern of frost, that is a good time to conduct a low cost, lab-tested soil/growing media sample. Although there should be sufficient nutrients in the growing media used on a roof, it is proactive to have samples taken once or twice per year, even for juvenile green roofs, ones that are still in the establishment period. The first tests on a new roof set a baseline for that siteโ€™s nutrient makeup, so that every test after that point can be looked at in comparison. 

For more information, please visit – https://livingarchitecturemonitor.com/articles/importance-proactive-green-roof-maintenance-sp23

Green roofs, solar panels and digital monitoring: How the worldโ€™s buildings are changing

Installing M-Tray green roof

From older structures modernized using connected devices, to more recent developments which integrate sustainable and technologically-advanced design features, the buildings people live and work in are changing.

Itโ€™s clear that, as governments and businesses around the world look to increase economic productivity while reducing their carbon footprint, the built environment will need to be both functional and sustainable in the years ahead.

Itโ€™s a big challenge. According to the latest Global Status Report for Buildings and Construction, emissions stemming from building operations hit their highest-ever level in 2019.

 

Slowly but surely, however, change is afoot. Below, CNBC takes a look at some key features of three buildings that made the shortlist for the upcoming BREEAM Awards 2021.

BREEAM is a sustainability assessment method from the Building Research Establishment which covers infrastructure, masterplanning projects and buildings.

According to its organizers, the awards โ€” which will take place in March, virtually โ€” recognize organizations, individuals and projects deemed to be โ€œleading the way with significant achievements in sustainable building design, development and management.โ€

Center for Sustainable Landscapes, Pittsburgh, U.S.

Located at Phipps Conservatory and Botanical Gardens in Pittsburgh, Pennsylvania, the Center for Sustainable Landscapes opened in 2012.

The building itself has been designed to maximize daylight, while other features include using rainwater to flush toilets. A green roof provides insulation and is home to wide variety of plants, some of which are edible.

The site uses solar panels and a wind turbine to produce electricity, while geothermal wells โ€“ located hundreds of feet underground โ€“ provide heating and cooling.

When it comes to technology, a building management system can control, monitor and offer feedback on a range of metrics to boost energy efficiency.

This includes notifying users if conditions related to air quality, temperature and humidity are favorable enough for windows in some areas to be opened, providing natural ventilation.
 
For more on this story, please click here.

Sustainable Housing Represents a Win-Win for Everyone

Aluminium edging on edges of a green roof

January 2020 now seems like a lifetime ago. The way we lived, the priorities we had, the hugs we shared. Was that really us?

While our notions of safety, wellbeing and personal space have shifted dramatically in the last year-and-then-some, one issue hasnโ€™t budged an inch: Climate change. Sustainable living was the biggest crisis the world faced 18 months ago, and while our mobility patterns have changed somewhat thanks to COVID-19, the overall issue of climate change continues to run deeper.

Now that we are hopefully seeing the light at the end of the pandemic tunnel, itโ€™s time to move the issue of green living back to front and centre again. Did you know that cities are by far the biggest contributors to greenhouse gas (GHG) emissions? In fact, 70% of the worldโ€™s GHG emissions come from cities and 53% of Torontoโ€™s emissions are from buildings. Itโ€™s the by-product of living in a densely populated and prosperous urban centre; one that enjoys a relatively high standard of living while weathering dramatic shifts in climate patterns. 

The responsibility for igniting change rests with the homebuilding industry. With a renewed and urgent focus on sustainable homebuilding, Toronto can be part of the solution as we move toward a fully-functioning green economy.

 

The good news is that we have made significant progress over the past decade. Many condominiums are now allocating a certain percentage of parking spaces for EV chargers. Smarthome technologies are giving individual residents greater control over their indoor environments (and their energy bill). The number of green roofs cresting our cityโ€™s skyline has grown significantly. Every little bit helps!

The KING Toronto condominium by Westbank Corp and Allied Properties offers an excellent example in building toward a greener tomorrow. Inspired by a mountain range, the condominiumโ€™s revolutionary architecture incorporates over 200 plant species across the buildingโ€™s faรงade.

To view the full story, please click on the link below.

Sustainable Housing Represents a Win-Win for Everyone

Bringing Green Roofs To Royal Ascot

The M-Tray green roof at Royal Ascot

Royal Ascot is an annual Flat racing meeting held for five days in mid-June which is one of the highlights of the UK’s sporting year. Hosting 18 Group races (the highest quality Flat races), this year’s event is taking place and providing a welcome distraction from the current issues.

The Perfect Solution

Issues relating to accessibility and concerns relating to disruption during installation are common reasons for property owners assuming that the installation of a green roof may not be possible for their building. Particularly when it comes to retrofitting a green roof onto a rooftop area.

However, thanks to the modular nature of the M-Trayยฎ, we are able to provide a viable option for areas which are simply not suitable for other types of green roof installation.

Wallbarn is at the forefront of developments in the green roofing sector and has always provided products that combine top-quality ingredients with user-friendly, hassle-free maintenance. The purpose of M-Trayยฎ is to enhance rooftop living.

A Stunning Installation

As the trays simply clip together they are quick and easy to install. The vegetation begins to blend within days giving plenty of time to look their best before being exposed to the general public.

Once clipped together, the vegetation in the trays blends together resulting in a seamless green roof.

Ascot racecourse green roof

Here’s to a fantastic week at a truly iconic venue, known throughout the world!

  • For more on the M-Trayยฎ, please click here.

What Makes Green Roofs a Must-Have for Modern Cities?

Green roof single storey extension

Take a birdโ€™s eye tour of many of the worldโ€™s well-known cities and thereโ€™s one noticeable feature they have in common: a growing number of green roofs.

Whether itโ€™s carefully cultivated gardens on Chicagoโ€™s skyscrapers, urban farms nestled among Hong Kongโ€™s towers or grassy layers atop many of Copenhagenโ€™s large buildings, more cities have brought in planning laws mandating green roofs on new developments.

Toronto, for example, introduced laws for new buildings or extensions greater than 21,000 square feet back in 2009. Since then, developers have had to cover between 20 and 60 percent of their buildings with vegetation โ€“ and while they can opt out for a fee, fewer than 10 percent choose to do so, according to data from Torontoโ€™s City Hall.

Other cities have opted for more flexibility. In San Francisco, 15 to 30 percent of roof space on new buildings must incorporate solar panels, green roofs or both.

โ€œLocal government policy has and continues to be the major gamechanger as more cities aim to improve air quality, protect against flooding and heat stress during heatwaves, and build nature back into the urban environmentโ€
Isabel Scruby, Planning, Development & Heritage consultant at JLL

Itโ€™s a far cry from when green roofs first appeared 50 years ago when it was often charities or housing cooperatives leading the charge in German cities such as Dรผsseldorf and Stuttgart, today considered Europeโ€™s green roof capital.

Driving a greener future
Today, there are often financial incentives for going green. In Hamburg, green roofing measures for both residential and commercial buildings are subsidised with up to โ‚ฌ50,000 via the Hamburg IFB bank. In America, Washington DCโ€™s storm water regulations and Philadelphiaโ€™s tax credit scheme both encourage green roofs. In London, there are no such incentives. However, itโ€™s now home to some 42 percent of the UKโ€™s overall green roof space, in part through residential schemes such as Barnetโ€™s Collingdale Gardens and Islington Square.

โ€œSince 2008, there has been a clear drive in the uptake of urban greenery in London โ€“ specifically living walls and green roofs โ€“ as part of the Living Roofs and Walls Policy,โ€ says Scruby. The challenge is for those areas where there are low levels of greenery to improve, says Erin Williams, consultant in JLLโ€™s Upstream Sustainability Services team. โ€œThat will require more developers and existing real estate owners to embrace to the idea.โ€

While there are certainly practical issues to overcome, from transporting materials onto the roofs to ongoing irrigation and stormwater management, there are also benefits for investors and tenants. โ€œDevelopers or redevelopers sometimes need convincing of the benefits of a green roof on a propertyโ€™s long-term value and energy efficiency,โ€ says Williams. While utility costs vary between cities, the National Research Council of Canada estimates a green roof can reduce air-conditioning use by up to 75 percent.

And comparing the expected cost of a conventional roof with the cost of a 21,000 square-foot green roof, a 2006 study from the University of Michigan found that over its lifetime, a green roof would save about $200,000, with almost two-thirds of that in energy.

Appealing to modern tenants
While green rooftop space can be left vacant or landscaped for recreational use to help improve health and wellbeing among building tenants, some rooftops are going down a different route.

With greater public concern over climate change and a growing appetite for locally sourced produce, urban farming is starting to take off โ€“ with rooftops often offering high quality environments to grow fresh produce. The worldโ€™s largest urban farm, Agripolisโ€™ Nature Urbaine, recently opened on a central Paris rooftop.

For more information, please click here.

What Would Happen to Auckland If We Put a Green Roof and Green Wall On Every Home

M Tray module and flowers close up

Graham Cleary, founder and CEO of green architecture and landscaping company Natural Habitats thinks so too, and heโ€™s been on a crusade to green up our cities for 30 years.

A green wall or roof is essentially a panel of vegetation. Where a standard garden is horizontal, a green wall has been flipped on its side. The science is in how you put a garden on its side, make it light enough, and choose resilient plants that wonโ€™t outgrow basic maintenance. Natural Habitats uses a recycled polystyrene that mimics soil and incredibly, the plants react to it like soil. The panels of plants are light and can be easily moved and clipped onto a metal structure on the walls of the building.

For all you plant nerds, the type used are called epiphytes (perching plants). Epiphytes naturally perch inside other plants and are happy in tight spaces, and growing from heights. Natural Habitats uses natives, philodendrons, astelia, small shrubs from the pohutukawa family and orchids.

โ€œGreen walls and roofs contribute to better air quality, reduce city noise and provide a layer of insulation resulting in energy efficiencies. They can keep buildings cooler in summer and warmer in winterโ€
Graham Cleary
Natural Habitats CEO

โ€œGreen walls and roofs contribute to better air quality, reduce city noise and provide a layer of insulation resulting in energy efficiencies. They can keep buildings cooler in summer and warmer in winter,โ€ said Cleary. And they donโ€™t need as much maintenance as you might imagine.

The benefits of green architecture/biophilia

  • Mitigates climate change because plants absorb carbon
  • Aids climate change adaption because increased urban vegetation lowers urban temperatures and helps to slow storm water flows
  • Green walls and roofs are natural air filters. They convert carbon dioxide to oxygen and toxic substances, including those found in modern buildings, are removed from the air
  • Remedies biodiversity loss because increased urban vegetation will potentially provide increased habitat for urban wildlife
  • Improves human wellbeing because exposure to and interaction with nature has physical and psychological benefits for people. Hospitals built with green architecture have halved the bedtime of their patients and employees in green offices take fewer sick/mental health days.

Read more by clicking here.