Green garage roof - 7 steps to installing a green garage roof yourself

You can quite easily embellish the appearance of a dreary garage roof yourself, in just a few steps. A green roof returns a piece of greenery to nature, protects the roof membrane of the garage below and looks very attractive at the same time. We will inform you about the advantages of a green garage roof below, explain prerequisites for green roofs and show you in a simple step-by-step guide how you can easily install a green roof on your garage yourself.

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Benefits of green garage roof coverings

Green roofs are becoming increasingly popular in many locations. Not least because of the numerous advantages that green roof coverings provide. Even on small areas, such as a garage roof or a carport, you can enjoy the benefits of a green garage roof in simple means.

Protecting the seal of a garage roof

Garage roofs and their roof seals are exposed to influences of wind and weather with no protection. A green roof can help here. With a green roof, you are protecting your garage roof against hail, storms and UV radiation. This improves the longevity of the garage roof, and you will benefit from cost savings through reduced servicing, maintenance and renovation work.

Additional habitat for plants and animals

Permanent habitats for plants and animals is growing smaller and smaller as the number of waterproofed, sealed surfaces increases. By fitting your garage with a green roof, you are returning a piece of greenery to nature which was taken away by building your garage. Even small areas create an environmental compensation and provide plants and animals with a permanent and natural habitat.

Rainwater retention and relief for drains and sewers

The plants on an extensive green roof covering have the ability to store water. They can store the majority of the entire annual precipitation and only gradually release it back into the environment through transpiration. This special effect ensures that drains and sewers are offered relief during heavy downpours. This reduces the general risk of flooding. The plants store rainwater and release excess water with a time delay. But you can also benefit from this feature. Many municipalities and cities promote the installation of green garage roofs with financial subsidies in terms of the wastewater charges you must pay. Simply contact your local municipal authorities for more information.

Improving the microclimate

The microclimate is crucial for the quality of life of people and animals residing in this area. A green roof can help keep the surrounding air nice and cool and moist at all times through the transpiration process of stored rainwater. Especially in densely populated areas, this effect can prove to be pleasant and refreshing. In addition, green roofs have a filtering effect. These properties help to reduce the CO2 content in the air. Thus, you make a positive contribution to environmental protection with a green roof.

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Design, planning and preparing for installing a green roof

Before you can start installing you green garage roof, you must ensure that your garage or carport roof meets the prerequisites for a green roof. However, with a little manual dexterity and skill, you can quickly install a green garage roof yourself.

The most important prerequisite for a fitting a green garage roof covering is the static engineering parameters of the garage. If you want to retrofit a green roof at a later date, it is essential that you check the static engineering parameters of your garage. The garage roof must be able to bear an additional weight per unit area of approx. 120kg/m². If this load-bearing capacity is not guaranteed, you cannot install a green roof on your garage. If you are not sure whether your roof is able to bear the additional loads, make sure you have it assessed by a professional.

A certain inclination must be provided even for a flat roof. The garage roof should have a minimum fall of 2% (approx. 1° roof pitch). However, do not exceed a roof pitch of max. 7°, as such a build-up would not be possible without additional anti-slip, shear protection measures.

Of course, it is also important to make sure that the water run-off and seal of the flat roof has been produced properly. Is your roof watertight? Then installation of your green roof can begin.

Important: Safety first: During the entire installation process, constantly ensure that you stay a sufficient distance away from the roof edge and secure yourself against falling using appropriate protective measures (e.g. scaffolding, safety harnesses, handrails).

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Step-by-step guide to install a green garage roof yourself

You can easily install a green garage roof covering yourself using our simple step-by-step instructions in just 7 steps. First sweep the roof clean, in preparation for the actual green roofing work. Any damage to the roof seal or waterproofing which becomes evident must be repaired by specialist contractors.

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Step 1: Installing the root protection film

If the existing roof seal does not fulfil root protection requirements according to FLL guidelines, a certified root protection foil must be spread over the roof surface after cleaning. The roof surface must be completely covered with the root protection foil. If several sheets of the film must be laid, they must overlap sufficiently. The film does not need to be glued or welded in place. At the edges of the roof surface, slide the film under the sheet metal covering, if one is present. Where there is no covering present, allow the sheeting to protrude over the roof edge and then trim it flush with the top edge of the substrate once installation of the green roof covering has been completed.

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Step 2: Cut outs for roof drains/penetrations

After installing the root protection film, cut it out where there are roof drains or other penetrations. Carefully cut the film according to the size of the openings. Ensure the waterproofing seal beneath the film is not damaged!

Step 3: Installing a protective fleece

The protective fleece layer is loose laid across the entire surface of the roof with a 5 to 10 cm overlap between each run. The protective fleece is also drawn up to the edges of the roof and holes must be cut out for roof drains or other penetrations, corresponding to the root protection foil used.

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Step 4: Laying flat roof shell GDS 15

The GDS 15 flat roof shells are laid directly onto the protective fleece, previously laid. Individual shells are joined together using tongue and groove joints present. Please ensure that a small distance (min. 2 cm to upstands and upturned structural components!) is maintained from roof edges. In the case of skylights, roof drains, ventilation pipes or other penetrations, the shells can be cut out using a commercially available jigsaw according to the opening required, or the flat roof shells are laid as full units around the openings.

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Step 5: Providing gravel strips

We recommended providing a strip of gravel (grain size 16/32) 30-50 cm wide and 5-8 cm deep alongside all roof edges as well as on upturned structural components (upstands) and around roof penetrations. This will keep vegetation away from these areas, preventing plants from growing behind or beneath waterproofing. In addition, drainage areas are kept clear, allowing water to drain off properly. The gravel (or ‘ballast’) can be placed directly into the flat roof shells. Alternatively, the gravel can be placed on top of the protective fleece if, for example, the flat roof shells have been laid generously around corresponding openings or at a sufficient distance away from the roof edges.

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Step 6: Fitting the substrate

The substrate for extensive green roofing is placed directly into the flat roof trays and evenly distributed over the entire surface of the roof, with an installed depth of 8 cm. Tip: Lay out all substrate bags evenly on the flat roof trays, cut them open, pour them out and spread using a rake.

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Step 7: Installing sedum shoots

The sedum shoots (1 kg of shoots per 10m² of roof surface) are evenly distributed on previously moistened substrate, then lightly pressed in place or raked in. Next, water the entire area thoroughly once more. Check the moisture level regularly during the first 4 to 6 weeks and water again if necessary, depending on the weather. This is the only way for the shoots to take root sufficiently.

Servicing and maintenance for green roofs

Extensive green roofs have especially low servicing and maintenance requirements. In order to enjoy your green roof for a long time, you must nevertheless observe a few pointers for servicing and maintenance. Depending on the build-up and scope of your green roof, you can get by with one or two service visits per year. Once a year, non-native vegetation must be removed before it seeds. Even though sedum plants are largely self-sustaining, a slow-release fertiliser should usually be applied to the garage roof once a year in springtime. Clean and check roof drains, inspection shafts and gutters once a year and remove any contaminants. For more information on servicing and maintenance extensive greenery, see our Service & Maintenance page.

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Installing a green roof on your garage yourself - the full package

Our 10 m2 flat roofing package for an extensive green roof is the ideal complete package for a green roof covering for your garage or carport. With the help of the easy-to-understand step-by-step instructions enclosed, you can install a green flat roof covering yourself in no time at all. You will find all the information and tips required in the instructions. The best thing is: no need to worry about choosing the right plants. Together with the flat roofing package, you will receive a voucher for sedum shoots which you can easily redeem with us. We will then send you the sedum shoot mix in plenty of time. Nothing stands in the way of a green roof covering for your garage. Would you like more information about the complete package? Feel free to contact us by e-mail, telephone us or using our contact form. We look forward to receiving your enquiry.