What is a Green Roof? How to make Green Walls

Sedum_plant Growing in Polytunnels ready for sedum Mats blankets and trays

What is a Green Roof? Why Sedum?

Green roofs and walls have existed throughout the world for centuries.  Recent worries about sustainability, climate change, our carbon footprint and economic issues have meant that we are witnessing a growing interest in this form of green roofing wall coverage.  There are many types of Green Roofs or Walls that we can supply from the simple Sedum plant roof in our green roof systems to the wild life roof garden, or exhibiting your logo on the roof of office buildings.  In the future we would hope to see many more of these types of green roof, replacing the traditional tiled roof.  We are happy to offer a wide degree of service from simply helping you choose the correct plants to actually building/adapting your roof or walls for this form of coverage. On other pages on the site you can see how to make a green roof, the advantages of a green roof and DIY methods.

Green Roofs

The word Green Roof has come to describe a roof which is green in the economic sense.  In other words it is energy efficient or sustainable.  It has many different names such as a living roof, biodiverse roof, Sedum roof, brown roof, eco-roof, grass roof, turfed roof, etc. Basically, it is a living roof which is placed on a building instead of a conventional roof. There are various components that are necessary plus the main structure of the building must be tested before any attempt to put a green roof onto a large expanse of roof. There are numerous benefits surrounding green roofs including, helping to control water in areas of flash flooding as it absorbs more water slowing the release of rainwater.  It can be used as a filtration method capturing the run off water and using it for other uses such as brown water (flushing toilets etc). Experiments have shown that a green roof such as a Sedum Roof can help both with insulation during colder months and a cooling effect during hotter times. One of the main and most popular reasons for having a green roof, whether it be on your house, shed or garage is that it will increase the biodiversity of wildlife including insects and birdlife.  This makes it so much more attractive to look at than a conventional tiled roof. A green roof will also filter pollutants in the atmosphere especially carbon dioxide, lowering the carbon footprint but also helping lower disease rates such as asthma.  If all the roofs in London had green roofs the air would be far cleaner.

Financially it can increase the roof life considerably and nowadays goes a long way to even increase the real estate value of your property.  There are sometimes local tax incentives which may help but certainly in the Uk the local councils are very keen to promote the use of Green Roofs and sometimes will not pass building permission until a percentage of the roof is a green roof. 

 

Different Methods of Production of a Green Roof

Intensive Green Roof- A variety of plants and trees are grown for recreational purposes. Some maintenance is required. These roofs require a reasonable depth of soil and grow quite large plants, even trees. Often this type of roof is known as a "Roof Garden" and will require irrigation, feeding and is fairly labour intensive.  Often found on hotel roofs.   

Extensive Green Roof- Here there is a shallower layer of substrate planted with low growing species such as sedum, mosses or types of grass. This system requires minimal or no maintenance. The only real maintenance would be a once yearly feed in the early days and possibly some weeding if necessary although once established the plants tend to form a dense blanket like covering which deters the weeds. This type of living, eco roof can be established on a very thin layer of soil and usually has only either grasses, wild flowers, sedum or mosses.

Semi-extensive Green Roof- Slightly greater depth of substrate allowing greater diversity of plants and again low maintenance.

Green roofs can be grown on most pitches of roof, even on vertical walls to make an attractive green wall.

 

Components of Green Roofs

Green Roof Layers


This is the basic method used for intensive, extensive or semi-extensive growth. Different depths of substrate are used according to the type of construction required. There is also a modular version which Sedum Green Roof now supplies which includes the drainage and substrate layer in Pods.  The Sedum Modular or S.Pod/Sedum Tray comes in trays and can be placed straight onto a waterproof roof.

 

Sedum Modular Tray or S.Pod for a Sedum Green RoofSedum_Modular_System_Sedum_Green_Roof.jpg

Modular Sedum Pod which can be placed straight onto a waterproofed roof.

There are many types of vegetation that can be used. Sedum is ideal roofing material because it can withstand many harsh conditions including drought, heat, frost, snow, sea, winds etc. Wild flowers can also be used and different colour schemes can be designed for a green roof or a green wall. The aggregate substance allows the correct conditions for the chosen plants to flourish. The drainage layer used with the mats can hold up to six times its weight in water and is made from recycled materials.

 

 

Brown Roofs

Brown Roofs are also known as biodiverse roofs and are valuable ecosystems supporting varies species of plants animals and insects.  Various different areas of the roof are put aside for difference micro-climates. In other words an area perhaps with logs or gravels will provide different areas for different species.  Some can be built entirely for different species of spiders or for special species of birds who needs a specific diet of invertebrates or vegetation.  These can be integrated with a Sedum Green roof.  Barclays Bank in Canary Wharf is claimed to be the highest green and brown roof being 160m above ground level.

 

Blue Roofs

A blue roof is designed explicitly to store water, usually rainfall. Some are recreational others for water storage.  Those using temporary water rooftop storage are called Active and others Passive depending upon the different methods by which the drainage of the water is controlled. 

Costings

It is very difficult to cost a green or living roof as there are so many different varients but a well designed and installed green roof system will probably cost something in the region of 35 - 45 per square foot, although this can be less if the area is larger or it is a simple roof ie a shed or garage roof.  It is all dependant on the type of roof, the structure of the building and the type of plants used. For an estimate or just a chat contact Sedum Green Roof. We can advise you on your needs with no obligation. Just phone us and we can give you some ideas.

The disadvantage of the higher initial cost but the fact that a green roof protects the waterproof membrane from adverse weather conditions, it actually increases the life expectancy of a roof, sometimes double or even tripling life expectancy so in the long term works out economical. Financial incentives are now being offered in some countries.

 

 



We find that selling on line can get confusing and many people make mistakes.  Just ring us and we will advise the exact quantities needed to make your Green Roof or wall. Tel: 01747 830 176 monday - Friday 9am - 4pm.  Leave a message out of these hours or email us the details of your project to  info@sedumgreenroof.co.uk and we will get back to you. The green roof company.

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Benefits of Green Roofs

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Green roofs can provide important microclimates for insects, bird life and other even rare species.

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Green roofs can positively affect the heat produced by urban environments, (the Urban Heat Island).

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Green roofs significantly reduce the surface run off of rainfall. (A mechanism for Sustainable urban  Drainage Systems).