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How To Create A Green Roof

Different Types Of Green Roofing

Roof Garden / Green Roof in Revit Tutorial

There are two primary forms of green roofing: intensive and extensive. These are differentiated by the amount of vegetation utilized. While extensive green roofs can support up to 25 pounds of vegetation per square foot, intensive green roofs can hold 150 pounds per square foot.

Another factor that differentiates these styles from one another is the amount of labor required to maintain them. Intensive green roofs, as the name suggests, take a lot more work to manage, as they involve keeping the various types of plants separate and maintaining an actual garden. Extensive green roofs, on the other hand, are left to grow naturally and without restriction, taking care of themselves as they would in the wild, and thus only requiring yearly weeding and fertilization.

For private homeowners, the intensive format allows you to pick and choose which flowers you would like represented, enabling you to sculpt the aesthetic you desire. Extensive green roofs are designed only to be entered for their yearly maintenance, so they become more naturally overgrown than their intensive counterpart. This makes extensive green roofs harder to navigate, meaning individuals cant walk through the space to enjoy the flora.

Green Roofs Are Always Built According To The Type Of Roof

You can build a green roof on practically any kind of roof. The most important thing is to build your roof carefully, professionally and with quality materials. On flat and sloping roofs and steep pitched roofs, different materials and construction solutions are used for waterproofing.

A drainage layer is placed on top of the actual waterproofing layer of the green roof. It acts as a water reservoir for plants and ensures that excess water can safely escape from the waterproofing layer.

Loose green roofs should always be installed by a roofing professional with a firefighter’s certificate and knowledge of waterproofing. You can build a steep green roof yourself if you wish, as the materials used do not require the installer to have a firefighter’s licence. However, experience with roofs and construction is an advantage. The installation instructions must be followed carefully to ensure that the green roof works. On steep roofs, it may be necessary to support the soil layers, for example with battening, so that the substrate does not run off.

In green roofs and roof gardens built on courtyard decks, the movement and thicker growing medium puts a strain on the structures. Their waterproofing layer is protected underneath the thermal insulation. This is called a reverse green roof solution.

Where Can You Grow A Green Roof

For most DIYers, a flat roof is the easiest option for a green living roof. Anything up to a 10° is considered a flat roof. This means that shed green roofs are a very popular choice along with log cabin and garage green roofs. Having said that, any outbuilding or garden building with a flat roof is a suitable route such as bike storage units.

Flat roofs are an easier option from a green roof construction point of view, but living roofs are able to grow on pitched roofs too. This means you can consider a house green roof or growing a green roof on an extension or conservatory.

With intensive green roofs, you can consider any size or type of building as long as it can cope with the structural loading and irrigation requirements.

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Green Roof Growing Substrate

To successfully grow vegetation on your green roof, you need to choose the right substrate or growing medium. It is a common mistake to think that you can only use soil. This is not the case and is frequently not the best option.

It is also a common mistake that sedum mats and sedum blankets dont require an additional growing medium and can be laid upon the drainage and filter layers. Although the roots of a sedum blanket are relatively shallow, we would always advise that additional growing medium is provided. A depth of 50mm works best but a minimum depth of 20mm is acceptable in some cases.

For other types of vegetation, you want a growing substrate that is light-weight, aids with drainage but is absorbent enough to retain water to adequately support your plant growth. Its a fine balance and will depend on what you plan on growing.

Many green roof growing mediums are specially designed, being a custom blend of aggregate and organic materials based on your needs.

There are various green roof substrates on the market. These often include a few different materials blended together to create the characteristics needed for good vegetation growth. These include bricks and aggregates, compost, medium clay soils and even volcanic rocks like lava and pumice .

Best Plants For Green Roofs

Create Your Own Green Roof Garden

Green Roof Plant Mats are the most perfect way of getting a great mix of plants for your roof.

Available at:

Or you can choose and plant your own selection. Sedum plants come in many lovely varieties. I have listed some possible contenders below.


You can help to improve air quality and reduce noise pollution in your garden and surrounding areas by planting a hedge, heres how hedging works. Best Plants To Combat Pollution In Your Garden

I hope that this article has been helpful to you, encouraging you to create a green roof on your garden shed. Even small spaces can be filled with plants to provide more, much needed greenery. Help the environment and wildlife and build your living roof today.

Please share this article with friends and family and on social media, lets grow green roofs everywhere.

If you have any questions about this or any other article then add them to the comments box below. I love to hear from you and I always reply as soon as possible.

Thank you

Happy Gardening

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Diy Planting A Living Green Roof

Green Roof, Photo courtesy Ryan Somma, Licensed under CC BY-SA 2.0.

One of the most important decisions when building a green home is choosing a roof type. Because the energy efficiency of a home often comes down to heating and cooling, it is of utmost importance that a green home has the right roof to provide insulation rather than letting valuable hot or cold air escape. In addition, a roof that requires frequent maintenance and replacing will contribute negatively to the environment by adding waste to landfills.

Heat-reflecting recycled metal roofing, recycled roof tiles, and other green roof products are all great options for energy-efficient and earth-friendly roofing. But what if your roofing choice could be all that and more? Living green roofs are not just eco-friendly and energy-saving they come with a huge abundance of benefits that other roof options simply cant compete with. And unlike other roof options, planting a living green roof is something you can DIY-install on your own!

What is a living green roof?

The General Services Administration has designed and maintained green roofs for decades, currently maintaining at least 24 green roofs in 13 cities around the country. Green roofs are defined by the GSA as vegetated roofs consisting of a waterproofing membrane, growing medium and vegetation overlying a traditional roof.

Main Points To Consider When Creating A Green Roof

There are a few things to consider before you begin creating a green roof.

The main points are:

The type of roof you wish to build a green roof onto

I am dealing with pent roof sheds but you can use the same method to build onto an apex shed or summerhouse. You could also create a green roof on refuse bin sheds, bike sheds, playhouses etc.

Main buildings will need more expert advice and possible planning consent.


The cost can be kept very low, and does depend on the size of the roof youre planning. Plant mats are available and are priced per square meter. You can also grow plants from seed or propagate from existing plants to keep costs down.

Materials requiredA list is provided below

Which plants to useThis depends on the desired effect but generally sedums, Sempervivums or wildflower mixes are used

Roof pitchThe ideal angle of the roof is between 1 and 5 degrees. If the roof is completely flat rain water cannot run off, leaving plants waterlogged. Too steep a pitch and the plants can become scorched and dehydrated.

AspectWith all garden design schemes, the rule right plant right place applies. Green roofs are no exception, sedums, grasses and wildflowers need some sunshinea roof in deep shade will not provide the best growing environment.

AccessibilitySome occasional maintenance of your green roof is required. Can you safely access the roof to maintain the roof and plants?

Is the building sufficiently strong enough to bear the weight of a green roof?

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Root Barrier For Green Roofs

Its recommended to include a root barrier above the primary waterproofing layer to prevent any roots causing damage to the structure. These tend to be thin polyethylene plastic membranes that can simply be laid across the waterproofing layer and joined with tape.

In intensive roofs, root barriers are essential due to the potentially more wood-like and vigorous roots of the vegetation.

Photo of green roof plant roots by Kyle Ellefson on Unsplash

What Kinds Of Landscape Design Should I Use And What Plants Can I Grow On My Roof

DIY living green roof installation

Plant selection depends on a variety of factors, including climate, composition and depth of growing medium, loading capacity, height and slope of the roof, maintenance expectations, and the presence or absence of an irrigation system. A Green Roof Professional would be able to advise you on suitable plants and design of the plantings. Contact a GRP via our GRP Directory.

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Green Roof Drainage & Irrigation

As weve already mentioned, a green roof drainage layer is an essential part of your green roof. Drainage is so important in a green roof because you need to be able to effectively deal with large volumes of water while still providing sufficient water for your green roof to thrive.

The green roof drainage layer is usually a HDPE membrane. These can feature cavities or cups that collect water. Water is retained in these little reservoirs until it is required when it is drawn back up by the vegetation.

Any excess water such as from heavy rain, passes through perforations in the HDPE membrane. The water then travels through to a drainage space below where it can be safely evacuated via the drainage outlet.

This prevents too much water accumulating and potentially damaging the roots and causing harm to your green roof.

Note: Our PermaSEAL 8 Green Roof Drainage Membrane does not have perforations. There is still a cavity created below the geotextile fabric as the cups are facing a different way compared with our PermaSEAL 20P Green Roof Drainage & Storage Membrane. For inverted warm roof designs you would have to install the PermaSEAL 20P Green Roof as the perforations aid evaporation, reducing condensation risks.

When looking for a green roof drainage membrane, you want to look out for:

  • High quality HDPE plastic
  • Easy to install and handle

Green Roof Irrigation

They Add Commercial Value

Green roofs on buildings have commercial value. They can be used as public gardens, restaurants, and childrens parks. They can be effective to regulate the ever-growing infill projects in urban areas. These rooftops can be used as sites for urban agriculture. This will reduce a communitys urban footprint through the creation of a local food system.

Uncommon Ground, a restaurant in Chicago, is growing some of their ingredients on the roof above. Sky Vegetables, as plans to build and operate rooftop greenhouse gardens on supermarket rooftops. Living roofs on educational facilities can be useful to teach students and visitors about biology.

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Caring For Green Roof Plants

Green roofs – including liverwort roofs – should be watered during the dry season. Proper fertilisation of plants contributes to their well-being. Liming the liverwort cover every four years or so is good for liverwort. Otherwise, liverwort can manage with a little fertilisation. However, spring fertilisation can encourage liverwort to flower. In autumn, it is a good idea to remove excess leaf litter and conifer needles from the roof to prevent them from acidifying the soil too much.

The Cost Of Green Roofs

5 Ways to Create a Thriving Green Roof

The cost of a green roof varies between $15 and $25 per square foot for intensive roofs, and between $10 and $20 for extensive roofs. Much of this cost comes from the soil and growth concentrates, as well as the plants. This cost increases depending on whether youd like your plants to be individually planted as opposed to pre-grown via a vegetation mat, and may also affect the ability and convenience of getting the materials needed. While none of these components are particularly hard to find, transporting them to your location may be expensive.

This is starkly juxtaposed to the cost of a green roof in Germany currently, which sits at between $8 and $15 per square foot. This is due to the newness of the industry and technology in the U.S. and the increase in custom projects associated with the market here.

When establishing a budget for a project like this, one should consider the long-term maintenance involved as well. While this may be sporadic if one is getting an extensive green roof, it is still an expensive process depending on the size. For some companies, this is a free inclusion that comes with their services, but generally, its between $0.75 and $1.50 per square foot.

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What Do I Need To Know About My Building Before I Initiate A Green Roof Installation

You will need to know the slope, the structural loading capacity, and existing materials of the roof, as well as the nature of any drainage systems, waterproofing, and electrical and water supply in place. You should also consider who would have access to it, who will perform maintenance, and what kind of sun and wind exposure the roof gets.

For a deeper insight into green roofs and green roof designs, attend one of our Green Roof Professional Training Courses, or purchase one of our course textbooks from the Green Infrastructure Store.

Why Should You Build An Eco Roof

Living roofs not only look beautiful but offer many advantages. In nations like France, Switzerland, and Canada, laws have been enacted for commercial and residential buildings to have at least partly green rooftops. There are companies sprouting up all over the world to help you make the transition.

Below, we’ll first take a look at the benefits of living roofs, then discuss installation.

Landscape planners will have the opportunity to make sculptured roofscapes, so that cities appear to be verdant hills and valleys. Streets will become shady routes carved through the undergrowth. Roofs will become mountain tops. People will become ants.

English architect and garden historian Tom Turner in his book, City as Landscapes

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They Help Lessen Noise Pollution

Loud music, sounds from televisions, people chatting on phones, traffic, and even barking pets are quite common noises in urban areas. These things have their consequences such as causing hearing problems, disruption in sleep, cardiovascular disorders, etc.

The combination of soil strata and the plants helps to absorb, reflect, or deflect sound waves. Green roofs can also reduce the level of electromagnetic radiation that is rampant due to mobile phones and other electronic devices.

How To Build A Green Roof On A Shed

Learn how to make Green Roof Architect in Revit | Organic Roof

If you want to start small, and lower to the ground, a green roof can also be installed on a timber structure such as a shed. The process is much the same as when installed on a house, with a few key differences:

  • The roof of the shed will need to be reinforced to support the weight of the soil and plants.
  • The timber of the shed will need to be thoroughly waterproofed to prevent rot.
  • The drainage layer and filter layer are not usually necessary as the volume of water is less and can easily drain off.
  • A green roof on a shed is a great place to start if youre considering a DIY approach. Not only is it safer and cheaper, but it also gives you an opportunity to experiment with plants, watering and maintenance ready for any projects that involve your main roof.

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    How To Create A Green Roof On Your Garden Shed

    Developing additional green spaces is paramount to this planets well being. Natural green areas are becoming more and more scarce, particularly in cities and towns, we can help the environment by using all the outdoor space we have to grow plants in. So lets take a look at how to create a green roof on your garden shed.

    How To Make A Green Roof: The Structure Of A Loose Green Roof

    On a sloping green roof, waterproofing is generally provided by three layers of rubber-bonded waterproofing layers, the top layer being root-protected. A drainage and water retention layer is installed on top of the waterproofing layer.

    The water-retaining layer can be, for example, a thin layer of rock wool. The waterproof layer is to be topped with a substrate and selected vegetation, such as liverwort or meadow grass. The design of a sloping green roof can be, for example, a sloping pent roof or a so-called flat roof that tilts inwards.

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    Benefits Of Green Roofs

    There are various reasons why most people want to pursue a green roofing system, both for the home and the community.

    Community Benefits Include:

    • Creates an Aesthetic Look: It provides an aesthetic look to urban communities. Urban greening promotes an effective and easy strategy in beautifying the newly-built environment and increases investment opportunities.
    • Improves Heat Production: A green roof improves the overall heat produced by the building structures in urban settings, covering different surfaces that will generate more warmth.
    • Prevents Pollution: The plants in the green roof helps to prevent dust and smog distribution and catch pollutants found in the air.
    • Reduces Stormwater: It minimizes the need to manage stormwater that accumulates and the stress put on local sewer systems.
    • Increases Revenue: The amount of money and work required when constructing a green roof can create or increase revenue and jobs in local businesses.


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