Are All Green Roofs Effective?

Quite a common question and one where there is probably no definitive answer.

It depends.......why is it there, what is it expected to do, what species are present, where is the site [ location /climate] and how it was built.

A recent article in Scientific American online has had a huge response in comments, many debunking the assertion the green roofs don't work, as claimed by the author.

Truly, there is no real evidence presented - either way, in the many words delivered on the topic.

But how can a successful green roof be assessed?

While not an exclusive list consider the following claims that are made.

• Reduces roof temperatures and thus air conditioning and /or heating loads for the building
• Produces more oxygen in a city environment
• Absorbs CO2 and other gases by the plants and even some particulates or metals into the soils
• Uses rainwater and so reduces stormwater loads in the neighbourhood as well as absorbing materials in the rainwater [gases and particulates]
• Improves roof aesthetics
• Costs more to install and maintain
• May require an additional water source to meet plant needs in periods of water drought
• May allow food production on the site as a small food garden
• Must be maintained at some additional cost

This is far from a full list, but indicates that a green roof is not for all.

Careful design can do a lot to improve the situation and allow a green roof to function effectively at minimal costs.  While some push for native species on green roofs, that is not an essential feature by my views.  It has to function at modest cost and inputs, once established.

In the warmer regions, grass can be a useful species.  Yes, it may have to be mown sometimes, but many are tough species, and you can select those with minimal nutrition and mowing needs.

In Darwin there is a great green roof, which many do not even think about - the Speakers Green at Parliament House.  That is built over the roof of the basement car park, and uses zoysia grass - it generally looks fantastic!  This area is highly maintained and used intensively for functions, while being decorative.

In Singapore, the new water facility at Marina Barrage has a  very large green roof - again it is grass!

Some types of green roofs can be identified as intensive or extensive. [ Both examples above are extensive types, although the former could be argued over and is used frequently]. The intensive type often has garden beds, small trees, formal paths and grassed or untended areas with mass plantings as a mixed development and may be used intensively, while extensive green roofs are ones that are sometimes just grassed, or with mostly less tended scrambling plants, less if any in the way of paths and garden beds, and often not greatly used.

The article is worth reading but many comments are very critical of the author, often for failing to really understand the subject.  So yes, there are a range of views.
http://www.scientificamerican.com/article.cfm?id=why-manhattans-green-roofs-dont-work-how-to-fix-them&WT.mc_id=SA_CAT_SP_20130520

In my view the green roof can be a great asset, but need a degree of planning involving several different professional inputs is needed for successful development.

 
  

Green Walls Grow in Singapore and Malaysia

Policy changes and enhancements are driving more green walls and roofs in SE Asia.

Becoming very common in both Singapore and Kuala Lumpur, and now in many new developments.

A good example is the new Park Royal on Pickering Hotel in Singapore which is Singapore's first Platinum Green Mark hotel.  Quite an achievement...........and a lot of green walls help to reach this achievement.

In the foyer of Park Royal on Pickering

Green Roof and shading

 

 

Green Wall Systems

There is a lot of interest in building design as well as more general landscaping, to encourage the use of green wall and green roof systems as part of a sustainability drive in the industry.

While there is little use so far in Darwin, Singapore has been very active in integrating these approaches into building and the environment.  Yet, with hot weather here, the concept of green walls and roof systems does have a lot of merit.  It is well known that green vegetation can be a major factor in providing shade to building walls and roofs, thus reducing heat gain and improving sustainability of design - and appearances too

A new system from Elmich known as Versiwall does offer some interesting concepts including some very clever ideas for dividing and /or external walls that can actively reduce sunlight on building walls and reduce heat gain.

The system has a recyclable plastic frame with specially designed pots that lock onto the wall frame.
A new take on the idea of a wire mesh or similar wall .

The pots can be arranged to match the size of plants to give a dense or not so dense wall cover, at a reasonable cost, and have a specially designed ctch to eliminate the risk of being dislodged, for example, in storms.

Check out the system at www.elmich.com or see the photos below.  Pots are made of a very durable plastic and are modestly priced.

The system is very new to Australia, with the first designs being installed later in the month.
Watering is integrated into the system, and recycled or grey water use is possible.

 

 

Green Roof and Walls

The Elmich Effect -   The Largest Greenwall in the World!! .

 

Officially the World’s Largest Greenwall Project - Singapore ITE Headquarters & College Central                                                        Hats off, to our colleagues at Elmich Singapore, who have just completed the largest greenwall installation, in the world.  Standing at 35m tall and totaling 5,300 m2, Elmich VGM Green Wall modules transformed the campus walls, both internal and external, into facades of living green vegetation, in-line with the college’s Eco-Initiative to create an environment conducive to learning. The highly engineered Elmich VGM architectural living wall system uses UV-stabilised plastic modules and stainless steel support brackets and pilasters that enable easy mounting and dismounting of VGMs during installation and maintenance. Topped off with 2400m2 of Extensive Greenroof 2,400 sq m of roof space, over three campus blocks, was 'Greened' using the Elmich Extensive Greenroof system. VersiDrain 25P® drainage and water retention trays were placed directly over the waterproofing and overlaid with a geotextile and a lightweight engineered growing media. Pearl Grass was selected for its heat tolerance and low maintenance and an automated pop-up irrigation system was installed to ensure abundant growth, maximising the benefits of this greenroof.

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While this is actually part of advertising by Elmich, it does show the fantastic green wall and roof developed for this new building complex  in Singapore.

Even more interesting is the new type of grass used for the roof.

Pearl grass [ their term] is actually a dwarf variety of broad leaved carpet grass [ Axonopus compressus] , with broad leaved carpet grass common as a turf in tropical Australia.

Does it have a place in tropical Australia?  I would think it might.

Urban Stormwater Management – Smarter Solutions and Better Stormwater Use

While almost no urban sewerage system in Australia is designed to also handle stormwater, as is the case in some older cities, particularly in the USA, the management of stormwater productively is quite a challenge.  With our increasingly hard surfaced cities, the stormwater system has grown, usually channelling away water that previously would have often dissipated within the landscape where it was generated, often even into the ground, or at least nearby.

While there are places around Australia where the stormwater is planned to move and actually recharge local aquifers, with Mawson Lakes near Adelaide a good example, as is some stormwater even around Palmerston, recharging the aquifer under the city in the wet season.  Normally, most stormwater runs off, and is lost to local use.

With about 80% of contaminants on hard surfaces, being moved with the first flush of rain [even more in the tropics with the first break storms of the wet season], colleting that and filtering through land and used by plants is a major and distinct improvement to the quality of stormwater discharged into nearby rivers, creeks and ultimately the harbours and oceans.  Most of the pollutants are remediated by soil borne organisms.

But driving that change is difficult as engineering has dominated how urban stormwater has been managed and the usual method has been pipe, or surface hard channel it, away.

More localities are reconsidering this however, through design modification to use plant based drains and detention areas before excess water flows elsewhere.  Volumes handled by expensive engineered solutions are often decreased as is cost, and water is used productively near where it is produced.

Better design can actually increase volumes handled by bioengineering approaches, so often even reducing overall costs.  This type of approach may even be retro fitted at modest cost or with little disruption to existing facilities.

It is more difficult in monsoonal areas with major differences in urban water between the wet and dry seasons, but it is possible to modify designs to at least allow a reduction in irrigation in the early and late wet seasons by better using locally generated surface waters locally with better design of roads and local parklands.

Some projects have been finished in Sydney as well as overseas. There are some smart designs on the web site of www.atlantiscorp.com.au  used in Sydney, an Australian company in this design space.  See more here -  http://www.atlantiscorp.com.au/solutions/civil-engineering/road-solution-drainage .

More are being planned, with some further details here –

http://e360.yale.edu/feature/to_tackle_runoff_cities_turn_to_green_initiatives/2613/

And then there are green roofs, aimed at collecting and using water that falls on buildings and preventing much of that getting to street level – it helps cool buildings too, reducing heat load on concrete roofs.  More of these options are developing.

 

We just do not do enough of these more appropriate solutions here in the NT. 

Stormwater Management - Green Roofs Play a Part

The concept of using green roofs has more been around overall city heat mitigation, reduced heat absorption on concrete roofs, more oxygen in the city, even reuse of waste water.

Recent work has indicated that the 'green roof" may be significant in stormwater management, a slightly different outcome than was expected.

While Australia and many other regions do not have a single stormwater and sewer pipe system, some cities do. There the collection of stormwater on green roofs appears to greatly reduce the amount of stormwater entering the sewer system, and thus reduces the potential overflow, quite a problem for these types of systems.

In the areas with separate storm water and sewer disposal systems, it would seem that the collection of especially higher intensity storm rain, the event that often overloads streets and stormwater disposal designs, would also be enhanced, and less stormwater would flow through the system. And, even if it was partially reduced, it would most likely time shift and reduce the major flows, after the rain had flowed down through the green roof and then out down a drainpipe to the ground. The green roof would also assist with removal of pollutants, often in the rain in cities.

More details of the study here -http://www.enn.com/top_stories/article/42701

Green roofs lend themselves well to regions with some regular rainfall, year round. Has not been much development here in the NT, due to our very strongly seasonal rainfall - wet for half the year, generally totally dry for the other half, so plants require watering then.

There is a good example of a green roof in Singapore, at the Botanical Gardens. It seems to work well.

Food Prices WILL Go Up

Mankind has enjoyed several decades of falling food prices, and relative abundance. Some even say that food prices have really been trending down ever since about the mid 1800s, although there have been some periods where that has not been so clear.

Modern agriculture has improved productivity of most farm animals, crops and even trees and enhanced efficiency of the use of inputs such that more is produced for less.

Recent trends in agricultural productivity increases are much lower, a lot of the productive land is used already, some even disappearing into urban sprawl, and new areas are far less available, or have other constraints eg clearing of rainforest, and may even be less productive intrinisically.

Malthus and his predictions are back in the spotlight.

A recent short article from the Lowy Institue in Australia, a respected academic institue has examined this issue more critically.
link is here - http://lowyinstitute.org/Publication.asp?pid=1565 and the publication can be downloaded as a pdf.

We need 71% more food production to feed the world population of 9.1 billion [estimated] by 2050.

So far, it does not seem to be recognised as a serious issue, with R and D expenditure on agriculture still declining, and some are suggesting that it will be difficult to again obtain the agricultural productivity gains of the past 60 years. These are years in which use of hybrid crops, the development of the "green revolution" in Asia with both wheat and rice, etc etc all took place.

Genetic modification has been embraced by some.......and strongly rejected by others.

Many scientists do think that some form of major genetic advance will be needed to ensure this food will be produced, and that there will be significant changes in how and where food is produced. Will we see more food produced within cities? Many think so, grown in novel ways too.....even vertically on walls, replacing the lawn with a food garden, food grown on building rooftops and there will be greater use of recycled water and nutrients including organic materials eg compost. These are happening in some way already around the world.

At present there is a nett movement of nutrients from farms to cities, and it just about all goes down the sewer or into landfill. That might have to change.

Science might be capable to develop new food production systems but social and cultural adjustments might be needed too. They might be more difficult.

Less Greenhouse Gas - Modest Steps and Tangible Actions Work

A lot of the debate around alternate energy, energy efficiency and even a carbon price or tax has focussed on climate change. That nebulous, end of century effect that no one is really sure about whether real or imagined, and which sceptics of climate change then have great delight in demolishing any argument to do anything about issues now. I am not a sceptic of man driven climate change, but for many it is just a difficult concept.

The ex Governator - or maybe the ex Terminator - has had quite a bit to say over the past few days, while delivering a very well received address at a conference in the US. And it offers some common sense about effecting change.

His premise is that climate change is just too abstract for most people to conceive [ apparently especially Americans] and that those wishing to effect change at grass roots level and in society need to be focussing more on real effects now, tangible things. These include:

• job creation from green jobs related to mandated renewable energy use,
• reductions in oil use and hence dependence on other countries for energy,
• energy efficiency that offers real benefits in reduced costs due to efficency improvements in homes and businesses,
• health benefits from reduced use of oil,
• vehicle efficiency improvements to reduce fuel use,

among a range of issues.

http://news.cnet.com/8301-11128_3-20037752-54.html?tag=nl.e703

offers a reporters view of the address.

This seems a very pragmatic approach, well wrapped in some humour too, and does offer a way forward at even local levels. Getting back to the old cliche - "act locally, think globally' a catch cry slogan of the environment movement. And implies a degree of personal responsibility, in California's case also in some areas offering state support.

There have been a number of reports available of business case studies that created quite substantial real $$ savings by embracing energy efficiency, for example and many jurisdictions do have programs to assist in taking this approach and actions.

Also read an earlier post - http://abovecapricorn.blogspot.com/2011/02/how-to-effect-climate-change-now.html

Urban Agriculture - Concepts for 2050

While 2050 might be 40 years in the future, planning and development thinking has already been evolving about what agriculture might be like.

There have been options mulled over including : -

• agriculture and horticulture as part of green roofs on multi story buildings
• use of the vertical surfaces of building to have plants growing on the facades
• use of warehouses to convert to hydroponic production [ currently being done in some rundown city areas in the USA]
• local community gardens
• locally reprocessed and used organic wastes and water

and the most recent scenario is even more ambitious.

It is the integration of production, processing and sale of fresh produce including fish farming and potentially some animal production such as chickens and other poultry in an integrated manner in a single facility.

It also potentially offers urban recycling as presumably a facility might also require composts and recycled water.

The link is: -http://www.justmeans.com/Agropolis-Future-of-Urban-Agriculture/30772.html

It is an intriguing concept and it would have many advantages for many cool regions of the world.

It is reproduced below. Read and think........

Last week at the Nordic Exceptional Trendshop 2010, held in Denmark, one presentation took urban agriculture to the next level. A collaboration with NASA, you might even say it launched urban agriculture out of this world, and into the future.

The idea is called Agropolis, a combination grocery store, restaurant, and farm all in one building, employing the most advanced technologies in hydroponic, aeroponic, and aquaponic farming. As it stands, Agropolis is still just a mere idea, with little more than some cool graphics to back it up.

But regardless, Agropolis ushers forth a new wave of thinking about urban food systems.

The team behind the Agropolis concept proposes that this new generation of store would be an ecosystem unto itself, a finely tuned orchestra of parts in balance, that would not only be totally envrionmentally sustainably and friendly, but also just plain producing the freshest food around.

But what would all these innovative, NASA-inspired state of the art hydroponics and other high-tech solutions look like in practice? ............According to the vision of Agropolis, a customer would walk into a store that is covered in green. Vegetables growing on the walls as far as the eye can see. And below the floors one would see tilapia swimming, working in tandem with vegetables in an aquaponic system. You would buy a tomato that was literally just picked, from a plant that you can see in front of you. The store would bring a whole new meaning to local, and one-up the notion of hyper local, since all the food available to eat or buy would have traveled zero miles from the farm to the store. At most, just a few steps.

It all sounds grand, and more than a little space-age. But the challenge given to the team that came up with Agropolis wasn't entirely outside reality: Create a farm without relying on arable lad. As the Earth's healthy soil and other resources dwindle, it may not be out of the realm of possibility that a system like Agropolis be needed, particularly in urban areas.

And while urban agriculture has come a long way, incorporating all kinds of creative and innovative ideas and technologies, in order to make it work on a large and global scale it may be time for something as futuristic and high-tech as Agropolis. But imagine if, in fifty years, or some other future point, our grocery stores did include built in farms, how our relationship to food would change. For one thing, the variety of food we eat might change--are there some vegetables and fruits that can't be grown using these artificial systems? Would we only eat tilapia, and no other meat?

Other vertical and urban farm project proposals include a variety of "staple" crops and animals that all work seamlessly together. But is biting into a fresh, hydroponic, LED light feeding tomato really as good as getting one from your local organic farmer who's tomatoes ripen in the sun?

What will the foodies of this imagined future look like?

In this brave new world of urban agriculture, one this is certain: While Agropolis insists that the store/restaurant/farm will be a sort of ultimate consumer experience, it'll be a much different experience than what we have access to now.

Green Roofs and Food Production

After posting a note on using roofs as green roofs mainly for environmnetal benefits, there may be an even greater requirement that combines both environment benefit and the simple need to grow food, within the large world cities that are now developing.

In Asia especially, large urban conglomerations are rampant......cities with many millions of residents, dependent on outside areas for food, and the logistical chains that are needed to bring the food into the area.

I think the classic case is Singapore. Not only are they dependent on non Singaporean sources for food, the residents are now also almost totally divorced from the food production process especially of fresh foods, and people have little knowledge or understanding of horticulture or agriculture.

To add to the comments, Professor Julian Cribb, author of "The Coming Famine", said that Australian cities also needed to be aware of the issues, and the global food crisis was a forewarning of what could be expected as civilisation ran low on water, arable land and nutrients, and experienced soaring energy costs. He said the urban farmers of the future - who would primarily grow vegetables - would play a much larger role in the global diet. "We need new skills in designing this diet and developing the intensive vegetable culture needed to support it," he said. "This intensive urban veggie culture is an entirely new industry and will need a new professional - the urban farmer who can grow food on the roofs and sides of buildings, in intensive biocultures and by other novel methods to feed the megacities of 30 million-plus inhabitants. "If we don't, by 2050 we will have more than three-quarters of the human population - almost 8 billion people - living in places where they are totally without the means or the knowledge of how to feed themselves. "Our giant cities will be gigantic death traps, at the mercy of even quite minor glitches in regional or global food supplies."

In Australia ,The City of Sydney council has commissioned a report to look at ways to encourage the greening of rooftops. A report is expected before Christmas, 2008, which will examine the option of fitting green roofs on older buildings. The council already supports gardens in the city.

"Green roofs would create more open space and enhance bio-diversity," Ms Hoff the Deputy Mayor said. "They will also reduce energy consumption by insulating buildings, reduce stormwater run-off, reduce greenhouse gases and could be practical, too, by growing fruit and vegetables."

Green Roofs Australia executive Jim Osborne, a landscape architect, said councils and governments needed to provide incentives such as greater planning and monetary support for rooftop gardens. The benefits of these gardens had been established overseas but more scientific research examining Australian conditions was needed.

This last issue is critical, especially for tropical Australia. In this region, temperate class plants are usually just wrong to use, and a new group might be needed. Watch this roof space!

KISSS for Green Roof Applications

There is a new product by the KISSS group that is well suited to green roof applications. It is called Ebb and Flow mat

The KISSS Ebb and Flow Mat represents a giant leap forward in green roof technology. The mat is an integrated extensive green roof system that provides not only irrigation, but drainage and root protection. The Ebb and Flow Mat has several advantages over other systems, Most importantly, it is an "active" drainage system that intelligently manages the moisture level of your green roof soils. Additionally, this system is the most cost effective system on the market today.

The KISSS Ebb and Flow System is simple to install and saves a tremendous amount of labour. Additionally, it is easy to work with in the event that a roof leak should occur.
Simply roll out the Ebb and Flow mat onto the roof and overlap the mats as shown below. Finally, install your drainage system. Then you have an active drainage system, irrigation system, and root barrier all in the one system.

The KISSS Ebb and Flow Advantage
The perfect solution for an extensive green roof on structures that are sensitive to water loading. This system provides an active drainage layer while elimination water holding on structure.
Integrated design and roll out installation reduces labour and eliminates the need for many of the standard components within other green roof systems, making it the lightest and most economical system in the market today.
The system can be manufactured to be compatible with conventional green roof systems and add supplementary drainage, as well as effective irrigation.

An ideal system for green building initiatives like LEED.

Light weight, flexibility, and low cost make it a prefect fit for any retro-fit with a restrictive weight allowance or budget.

Green Roof Frequently Asked Questions

How does it work?
The KISSS Green Roof product irrigates the soil media above it, and assists in the drainage of the soil to keep it at optimum moisture content. It does this without the soil being saturated, as saturated soil forces out air. Air in the soil media is just as important as water to plants, and especially on a roof where the minimum amount of soil media should be used to minimize the loading on the roof, and maximize the run-off in heavy rainfall. The difference between the KISSS system and other green roof irrigation systems is that it can drain the soil media at a gentle rate, and if the media is drier than the irrigation system, the system will provide more water to the media via capillary action. This keeps the top few centimetres reasonably dry which reduces evaporation and weeds germinating, but keeps the lower layers moist which encourages deeper root growth.

What soil/media can be used?
Plants of any kind can be grown on a green roof and the only limiting factors are enough soil media for support, moisture, air and nutrients. We suggest a light weight media product and there are a few in the market eg CocoEarth media mixed with sands of a particular grade to give stability and hold water and nutrients that are required. These can be provided by the installer.

How durable is the material?
The materials in the KISSS product are not biodegradable. They are synthetics that are made from polyester and polyethylene and do not break down in soil and do not compress easily. The materials are made in such a manner so that the water and nutrients runs along the fibres but do not fill the fibres and only the pore spaces in between the fibres hold the water, soil and nutrients.

What about roots damaging the materials?

Roots can invade the materials and run between the fibres, but will not penetrate the fibres themselves therefore the fibres still maintain their functions. The drip line that is in the system to supply the water to the geotextiles is encased in the geotextile for protection and also to make sure the water flows uninhibited across the fibres. The system is made to encourage the roots to invade the system to provide a source of water and nutrients and not to just rely on the soil above the system.

Can the system provide nutrients to the soil/media?

Liquid injection can be used with the KISSS system to add nutrients at any time. The benefit of the KISSS system is that the roots are in direct contact with the fibres in the system so that if nutrients are supplied through the water then the roots get access to these in solution immediately, thereby reducing the amount of fertiliser required. Controlled release fertilisers can be used on top of the plant material or soil media and the rainfall and moisture in the atmosphere will make these available over time, but 30% less fertiliser will be required than the rate for potted plants.

What can I grow on the green roof?

You can grow just about anything from lawn to shrubs to small trees to cactus to ferns to veggies for the family and it all depends on what you want and the aspect and climate of your roof. The simplest solution is to just turf your roof and have a veggie patch or flower garden. Small areas can be grown with a simple UV stabilised corflute structure that can be laid out on the mat and filled with media and planted out with whatever you desire.

What if I don’t want a green roof but want to grow my veggies or herbs?

KISSS has an answer with the combination of their ebb and flow mat and the veggie box on the mat. This can be planted out with flowers, herbs or veggies. The unit is 4.5m long by 1.2m wide and 200mm high. It can produce a wide range of veggies and herbs for all the family and can sit in the backyard on the ground and be connected to the tap and only requires two irrigation cycles of one hour each per week in summer and once a week in winter. It uses drip technology inside the ebb and flow mat to spread the water to the soil. The Cocoearth media is optional and can also be sent in the mail and you will require 12 blocks for a 4.5m long unit costing $80 plus postage and handling. Nutrients can be added by liquid form or organic fertiliser mixed in by shovel or chemical fertiliser as slow release. The corflute box is UV stabilised and light weight, and the system will last for 7 years under normal sunlight if the materials are not damaged by mechanical means or animals.
For more details see - http://www.kisss.com.au/kisss_ebb_flow_mat/green_roof_applications