FAQs and answers

Absolutely. In summer the sedum will block heat, making a cooling installation redundant (thereby saving on extra electricity). Black roof covering gives off 80 degrees, a sedum roof 38 degrees

A Sam Groofing finish can be applied to any type of roof. On flat roofs by means of drainage panels and pockets; on sloping roofs using industrial-grade Velcro. With currugated roofs and profiled steel roofs this is possible up to a 45 degree gradient.

This is an excellent idea. The diversity of sedum species in our roofs will add an extra dimension to the garden.

In cities and towns in particular it is sensible to create cool spots and support biodiversity.

100% yes. Because it boosts biodiversity, serves as water buffer, reduces heat and – in the case of Sam Groofing – uses recycled products. And when the time has come to replace or scrap the roof, Sam Groofing is fully recyclable.

This depends first of all on whether the roof is flat or sloping. In case of a sloping roof the architect/contractor is consulted, to stay in line with the design of the building. The standard edge finishing for a sloping Sam Groofing® green roof is a black aluminium L-profile. To ensure proper drainage this profile has been perforated on the gutter side.
On flat green roofs the edges are usually finished with gravel. But here also the edges may be trimmed with aluminium L-profiles. With or without perforation.

When combined with solar panels, sedum will increase the panels’ efficiency. The sedum plants have a cooling effect. The cooler solar panels are placed, the higher their output. Common arrangements are: pockets placed next to the solar panels; or solar panels on one side, green roof on the entire other side of the roof. Sam Groofing can be applied to any roof surface, regardless of its exposure to sunlight.

Not every sedum species in our pockets is perennial or evergreen. Because of the great diversity of species this balances out prefectly. From April to October the colours will jump out at you, changing from moment to moment, as there are at least 12 different sedum species represented in the pockets. Growth habits and seasons also differ. One species will bloom at a certain time, another species on another day. This compares to a standard garden on the ground.

A traditional sedum mat is a relatively cheap product. To manufacture it profitably, 6 to 8 fast growing species are selected. In most cases they are exclusively ground cover plants. Higher growing species are rarely used. They grow more slowly and have a hard time developing in a thin sedum mat. Higher growing species are also liable to break when the mats are rolled up for transport. All in all this causes sedum mats to have a monotonous and low look.
Our green roofs will permanently sustain a much larger number of plants than ordinary sedum mats, including higher growing species. This guarantees a much richer and more varied Sam Groofing® green roof.

We divide the range of plants into three groups:

• Evergreen and ground covering
• Semi perennial and ground covering
• Deciduous and solitary

The plants vary as to flowering season, inflorescence, colour and shape. There are fine-leaved, evergreen ground cover species, But also solitary, broad-leaved and higher growing species. Up to 30 cm and more. Some have yellow flowers. Others white or red. Several species shed their leaves in winter.

Yes, Hhis is possible – in principle. However, we recommend not doing this. The range of our sedum species has been carefully tailored by our own breeder. This guarantees a beautifully varied green roof with different flowerings, seasons and colours. Adding other plants may disturb the carefully created balance. In large projects and with large volumes the customer’s specific wishes regarding composition and variety may be taken into account.

By default Sam Groofing consists of a very extensive range of at least 12 to 16 different sedum species. They have been carefully chosen and matched. Plug plants were selected because they help maintain a much wider variety of sedum species over the years than can be found on regular roofs of sedum mats. In nearly every situation this range performs extremely well.
In large projects and with large volumes the customer’s specific wishes regarding composition and variety may be taken into account.

Yes, But only with large projects and large volumes. And always in consultation with our own breeder. Because we want to be convinced that the chosen range is well matched and will ensure a beautiful green roof for many years to come.

Absolutely! By definition, greater variation in sedum species means greater biodiversity. In addition, a wider assortment with different inflorescences and flowering seasons leads to a greater diversity of insects. In this way, for instance, we can support and advance the bee population.
In the future we shall further boost biodiversity by employing e.g. ornamental grasses and herbs in our green roofs.

No. This has been shown in internal company field tests.
On sloping roofs the pockets are firmly secured to the roof construction by means of industrial Velcro. On flat roofs the elements are connected by dovetail joints. Also, the growing sedum plants will form a stable interconnected vegetative cover. Finally, practice has shown that green roofs are much less sensitive to ‘wind suction’ than regular roofs.
In the course of 2023 the wind sensitivity will be tested and certified by external parties.

In principle all green roofs are relatively unsusceptible to wind suction because of the sedum. This is no different for the Sam Groofing® green roof. Therefore it can be applied at greater heights. If required, the panels and pockets may be either joined together or attached to the roof surface with industrial Velcro. This will further increase wind resistance.

During summer a green roof will be moist most of the time. The moisture evaporates in dry, warm periods, keeping the roof temperature down. Also, the green roof itself has a cooling effect. Because the plants absorb heat during the day that is given off at night. Next, the air buffers in the substrate afford insulation. Finally, many traditional roofs are covered with dark tiles. Solar radiation makes these roofs much hotter than a green roof. All these factors combine to keep the building itself cool.

No. Unfortunately this is impossible. It strongly depends on the weather and the resulting growth parameters of the sedum roof. As we all know, the weather varies greatly. Wageningen University has calculated that 20 m² of green roof on average produce sufficient oxygen for one person. Because of its wider plant range a Sam Groofing® green roof will capture more CO2 than regular roofs of sedum mats.

We made the deliberate decision to manufacture the drainpanels under the pockets out of ‘Post Consumer Waste’. This is waste from the end user (such as organic waste, waste paper and plastic packaging that a consumer throws in the bin). The frames are made from ‘Poly-Al’. These are waste flows from, among others, milk and juice cartons and recycled shampoo bottles. This way we contribute to meaningful waste recycling.

We made the deliberate decision to work with so-called ‘plug plants’. These are either individual sedum plants or bunched mixes of several plants. Our breeding spaces contain 450 plug plants per m². These are planted in the pockets with a density of 30 plants per m². This way 1 m2 of growing surface is turned into 15 m² of green roof. Every m² of breeding space is used at least twice a year, so that we can turn 1 m² into more than 30 m² of green roof per year. In regular sedum mat cultivation 1 m² of cultivation space becomes 1 m of green roof. This makes our demand on expensive and scarce cultivation soil considerably lower and with it our environmental footprint. To build on this even further, our plug plants are grown chemical-free.

No. The irrigation fabric (top side of the pocket) remains UV stable for at least 8 years, but long before that it will have been covered by the sedum and not be exposed anymore to solar radiation. The fabric is also resistant to bird pecking. A special casing around the roots of the plug plants anchors them firmly in the pockets. This also minimizes the risk of damage inflicted by birds pulling on the plugs.

Our production location is right in the middle of the Netherlands. Centrally located for our, mainly Dutch, suppliers and for our customers. Our internal transport equipment is fully electrical. Our production line was designed in such a way that there is hardly any waste.