FAQ's vegetation blankets
What are vegetation blankets?
Sempergreen’s biodegradable vegetation blankets comprise a coconut fibre carrier planted with different kinds of Sedum, optionally enhanced with (ornamental) grasses, herbs and wildflowers. The plants take root in the coconut fibre carrier and a special substrate developed by Sempergreen®.
What are vegetation blankets used for?
Sempergreen’s pre-cultivated vegetation blankets instantly provide mature roof and ground covering. At least 95% of the vegetation planted in our blankets is already thriving prior to delivery, ensuring that a green result is achieved immediately upon installation.
How much do the vegetation blankets weigh?
Vegetation blankets weigh between 10 and 20 kilograms per square metre, depending on how moist they are.
How much does a living roof with vegetation blankets weigh?
A standard Sedum roof with vegetation blankets weighs approximately 85 kilograms per square metre. If necessary, a lightweight construction can be used to reduce the weight to approximately 35 kilograms per square metre.
What do the Sempergreen® products cost?
All prices can be requested via the contact button. We will contact you within one working day.
Can a green roof (with vegetation blankets) be installed on any type of roofing material?
Vegetation blankets can be installed on any type of roof covering provided the roofing material is waterproof and resistant to root penetration.
Does a green roof with vegetation blankets create a waterproof roof?
No, if the roof is not waterproof, waterproof roofing material will need to be installed first.
How long can vegetation blankets stay rolled up?
That depends on the temperature, but generally for no longer than 24 hours. We recommend the blankets be installed immediately when temperatures exceed 20° C.
How many square metres of vegetation blankets can be stacked on one pallet?
Approximately 50 m² of vegetation blankets fit on one pallet.
What is the maximum pitch for a green roof with vegetation blankets?
Basically, vegetation blankets can be installed on roofs up to a pitch of 45°. Sempergreen® has developed various systems with different build-ups, depending on the pitch of the roof. Sempergreen® therefore provides solutions for any kind of roof.
What maintenance is required for a green roof with vegetation blankets?
A green roof with vegetation blankets requires little maintenance. Still, the roof needs to be checked once or twice a year to see whether any unwanted vegetation has taken root. Also, the drains need to be checked for clogging as no water may collect on the roof. This is harmful for the vegetation. Please also take a look at our maintenance instructions.
Does a green roof with vegetation blankets require fertilisation?
In most instances, fertilisation is not required if an extensive roof garden substrate has been laid under the vegetation blankets. In some situations, however, it may be necessary. We therefore recommend that you allow for fertilisation every spring.
Note: If a lightweight system has been laid under the vegetation blankets, fertilisation is required at least twice a year.
Does the coconut fibre carrier in the vegetation blankets shrink?
The coconut matting on which Sempergreen cultivates its vegetation blankets consists of a loose layer of coconut fibre. Coconut fibre does not shrink by nature. Given the loose build-up structure of the coconut fibre carrier, the vegetation blankets will not shrink.
Still, there are roofs on which some vegetation blankets shrink. Why is that?
There can be two reasons for this:
1. Often, the fibres of the carrier used for those vegetation blankets are woven or bonded instead of lying loose. Examples are blankets made of polypropylene membrane, sheep’s wool and bonded coconut matting. Sempergreen has therefore deliberately opted for high-quality loose coconut fibre mats containing no chemical extracts.
2. The vegetation blanket was installed during a hot, dry period and did not take root in the subsoil (or substrate) immediately after installation. This is because the substrate was not wet enough when or immediately after the vegetation blanket was laid. We therefore always recommend that you water your vegetation blanket immediately after installation.
Can a green roof with vegetation blankets be installed at any time of year?
Yes, except in sub-zero temperatures because then the vegetation blankets cannot be rolled up.
What arrangements can be made to transport Sempergreen® products?
You can opt to collect the products at one of our locations around Bunnik (in the Netherlands), or alternatively you can have Sempergreen® arrange for transport (throughout Europe ). For rates please contact our sales department at +31 (0) 343 539 699 or via info@sempergreen.com.
What is the average delivery time?
If the products are in stock the delivery time is approximately one week.
How can birds and other animals or pests be kept from damaging the vegetation blankets?
The vegetation blankets are not very sensitive to animals or pests; however, at certain times of the year birds can cause damage when collecting nesting material. This will only be noticeable if a large flock of birds pecks away at the vegetation blankets over an extensive period of time. As soon as you notice this happening, please contact us and together we will find an appropriate solution. Environmentally and animal friendly spraying agents are available to keep birds at bay. (www.pireco.nl)
Can you walk on a Sedum roof?
Yes, you can walk on a Sedum roof; however, so as not to damage the plants, we advise against walking on the vegetation in sub-zero temperatures.
Does Sempergreen® install green roofs?
No, we leave that to our customers or other parties with whom we collaborate, but Sempergreen® can provide advice and guidance concerning your project. Should you wish customised advice, please follow the link to our Advice Centre and contact us!
