Roof suitability
If two adults can stand on the roof without problems, the roof is usually strong enough for the lightweight sedum roof system (±45 kg/m²). To be sure, a structural engineer can take a look.
A green roof weighs between 40 and 60 kg/m² on average, depending on layer thickness and water saturation. A standard green roof weighs around 75 kg/m² when wet.
No, not every roof is suitable. The roof must have sufficient load-bearing capacity and be in good condition. Always have a structural engineer or specialist calculate whether your roof can support the weight before you begin installation.
Yes, a green roof can be installed on a gently sloping roof. What is important is that the construction for each layer is correct, that the water drainage works properly, and that there is appropriate edging or curbing to prevent sliding.
Sedum cassettes are usually used on gently sloping roofs up to about 15 degrees. Higher slope angles often require a system specifically designed for pitched roofs.
A special system, such as the sloped lightweight green roof package (10-25°), can be used for roofs with a slope angle of 10 to 25 degrees. This package is designed for pitched roofs and helps keep the structure stable.
It depends on the roof and the desired processing. Sedum cassettes are modular and practical, especially for smaller roof areas and up to about 15 degrees. Sedum mats provide a continuous sedum layer and are often chosen for larger roofs.
Weather & water needs
Sedum needs about 4 to 6 hours of sunlight daily to grow well and limit moss formation.
Some sedum species can grow in shade, but flowering will often be less profuse than in sun.
Moss is not directly harmful, but it can indicate too little sun, nutrition or water drainage. Proper maintenance prevents excessive moss formation.
Green roof installation
Yes – with the right materials and manual, this is doable for almost anyone.
Installing a green roof is not considered difficult by many. It is often accomplished within a few hours. It does help to do it in pairs. The sedum mats saturated (after a rain) can be heavy and muddy though so don’t put on your best clothes.
This depends on the area of your roof, but most people don’t spend more than a few hours doing it. Make sure you work with two people; not only is this safer, but you also work a lot faster and more efficiently. As an indication, our installers install a 30 m² green roof in a working day when working alone.
Gravel is optionally used between the sedum and the eaves. This prevents the sedum from growing through there and possibly leading to leakage.
You bet! On our socials, we post weekly content about installing green roofs!
Drainage ensures that excess rainwater is properly drained, keeping plants from drowning and protecting the roof structure.
Proper drainage prevents leaks, moss formation and damage to the roof layer. It extends the life of your green roof.
There are drainage mats, crates and gravel layers, depending on the type of roof. Flat roofs require different solutions than sloped roofs.
Check drains at least twice a year, removing leaves or debris and making sure drains are clear.
Maintenance & care
Yes, a green roof is low maintenance but not maintenance free. At least twice a year maintenance is required.
Twice a year: in the spring and in the fall.
Remove weeds, check drains, fertilize and check overall condition.
Not normally; only during prolonged drought may additional water be needed.
Twice a year: once in the spring (April) and once in the fall (September).
The sedum may deteriorate, weeds may dominate and water runoff may become clogged.
Products & selection help
Pay attention to whether your roof has sufficient bearing capacity, what type of system suits your situation (such as lightweight or cassettes), and whether you want to install it yourself or prefer to have it done. Also check to see if you qualify for a subsidy.
Do you have a lightweight roof structure? Then go for a lightweight green roof. Want quick results? Choose sedum mats. Do-it-yourselfer? Then cassette systems are perfect.
Order the best sedum directly from Sedumworld, of course, for the best price!
Learn all and more about sedum and why it is so suitable for roofs! Read: What is a green roof?
Package of 18L water buffer: approx 37kg/m² dry, 55kg/m² saturated. Package of 27L water buffer: approx 53kg/m² dry, 80kg/m² saturated.
With proper maintenance, sedum cassettes will last 20 to 40 years.
Solar panels & green roof
Yes, solar panels on green roofs are quite possible. It is important that construction, drainage and accessibility for maintenance be included in the plan from the beginning.
The key points are: adequate roof bearing capacity, clear areas around drains, walkways for maintenance, stable edge finishing and a mounting system that allows inspection and cleaning.
Yes. A clear zone should be left around drains and penetrations to allow inspection and cleaning and to prevent blockage. Along eaves, a clear zone helps ensure a neat and stable finish.
A green roof can keep the environment around the roof cooler. In practice, this can be beneficial to the performance of solar panels, especially on hot days. Yield also depends greatly on location, slope angle, ventilation and shade.
Longevity & insulation
A well-maintained green roof will last 40 to 60 years. Because it protects the underlying roofing from UV rays and temperature changes, it often doubles the life of the roof.
A green roof can increase home value by 5 to 10%, depending on factors such as surface area, energy savings and appearance. Buyers see sustainable modifications as a worthwhile investment that will future-proof the home.
Sure. A green roof provides additional thermal insulation: It retains heat in winter and prevents overheating in summer. This lowers your energy costs and increases living comfort.
Delivery & Storage
In cold weather, roll up for up to 2 days, in warm weather up to 1 day. Store them out of the sun.
Cost and subsidy
From ±€42/m² (material only), excluding accessories
The price varies on average between €40 and €140 per m², depending on material choice, roof type and whether you install it yourself or have it done.
Yes, DIY installation is usually cheaper, but requires knowledge, time and preparation. Professional installation offers warranty and less risk.
Craftsmanship, speed, tight end result and certainty of details in installation.
Yes, many municipalities offer subsidies for green roofs. Check your municipality’s website or our grants page.
You can easily apply for a subsidy through Sedumworld’s subsidy page. There you can see an overview of all municipalities. Is your town listed? Click through to the right page, fill in the application form and follow the instructions. Usually you need a quote, so ask Sedumworld for one right away.
Always apply before you begin construction of your green roof. Applications afterwards are almost always rejected. So make sure you get approval first and then order your materials from Sedumworld.
Not always. Many municipalities only subsidize flat roofs or pitched roofs with a certain pitch. In addition, your roof structure must have sufficient bearing capacity and your system must meet technical requirements, such as water buffering.
This varies by municipality, but on average the contribution is between €15 and €30 per m². Some municipalities offer a fixed amount, others work with a percentage of the investment.
Most private homes do not require a permit for an extensive green roof. However, it may be required for larger or listed buildings. Always check with your municipality.
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