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FAQs

FAQs

Sedum is an evergreen, succulent plant, the natural properties of which make it extremely suitable for roof greening.

Succulents are plants that store water in a part of the plant. Sedum stores water in the leaves, and this is why Sedum is often referred to as a leaf succulent.

The metabolism of Sedum differs from other plants, in that, at night, carbon dioxide is absorbed through the stomata and converted into Malic acid. During the day, under the influence of sunlight, the Malic acid is decomposed and photosynthesis takes place. The stomata in the leaves are only open at night and during the hot and dry day, moisture loss is minimised.

Thanks to it’s natural properties, Sedum requires little maintenance when used for green roofs and generally only requires attention twice a year which includes removing weeds carried by the wind and applying fertiliser several times a year.

Unlike grass, there is no need to mow it, which makes it perfect for hard to access places such as roofs

Sempergreen Group was founded in 1996 with the mission of growing and supplying innovative Nature Based Solutions that make life in our urban areas, towns and Cities greener, cleaner, better for our Health and Wellbeing and increasingly important, Biodiverse…..now, and for generations to come.

Sempergreen is a Global Company with many nurseries and offices around the World and Sempergreen UK Ltd has recently been set up in response to the growing demand for great quality Green Roofs.

Our knowledge is based on a strong foundation of 25 years’ experience, growing our plants in our nurseries around the World, and from extensive testing by our product development & innovation department. This ensures we have been able to develop the best quality products on the market with the following benefits:

  • Sempergreen products are of the highest quality
  • Upon delivery, your green roof is always immediately 95% covered
  • Sempergreen always delivers directly from stock from it’s own nurseries, which means delivery times are short
  • Our green products are produced completely free of pesticides and therefore make a positive contribution to the living environment of bees and butterflies

Web shops that carry the Sempergreen Certified Quality Mark, demonstrate that they are a certified seller of Sempergreen’s quality products for green roofs.

These retailers have been hand picked by Sempergreen, which means you can be confident that the web shop guarantees the best quality, reliability and service. 

Yes you can depending on the size of your project.

We offer specially tailored DIY packs with instructions and videos for your installation. See our installation page for more information and videos.

We are also able to introduce you to an experienced installer from our preferred network, just give us a call and we can advice on your best course of action.

Delivery is dependent on what Goods you purchase.  The website will automatically calculate the delivery charge, as a general rule, one pallet costs £55 + VAT – this will apply to all Sedum Systems and Click n Go Sedum and sedum products.  Purchases of smaller items from the ‘products’ have a flat rate of £20 + VAT per order.

We have a standard lead time of 4 days – however if you need your items sooner – please email [email protected].

Please check out our Delivery and Terms and Conditions pages for more information.

No, the transporter will deliver the goods to the kerbside only. It is your responsibility to unload the pallets and ensure that there is appropriate access for delivery.

Please check out our Delivery and Terms and Conditions pages for more information.

 

Yes you can.

The building must first be checked, to ensure that it is strong enough to carry your green roof. If you don’t know the weight bearing capacity, we offer a lightweight solution, which can be installed on most roofs.

The waterproofing on your existing building must be in good condition.

Yes. The surface must have a waterproof covering before your living roof is added. Most roofs will have one of the following:

  • Single Ply 
  • GRP Fibreglass
  • EPDM Rubber
  • Felt
  • Concrete

The addition of a sedum green roof will protect your roof from extreme weather conditions such as heavy rain, ice and intense sunshine, which actually increases the lifespan of your roof.

A green roof also cools the roof below which in turn, reduces fluctuations in temperature and exposure to UV light, which can damage the waterproof layer over time.

We have a lightweight solution if you don’t know the weight bearing capacity and if you prefer to find out and want to explore having a soil based substrate, which is heavier, then a structural engineer should be contacted.

There are a few reasons:

  • Aesthetic: some roof designs use stone areas to create artistic patterns or even a simple border to add character and a “picture frame” look.
  • To act as a Fire break: the FLL Guidelines and the GRO Green Roof Code include requirements for the provision of fire breaks within green roof design
  • Wind resistance: particularly in blustery areas, a stone border can be used to prevent the chance of wind uplift pressures on the green roof
  • To prevent debris: a stone border can effectively stop wind-borne plant parts and debris reaching the edge of the roof and gutters

Yes. A slight pitch is preferable; if over 15 degrees please contact us for advice and guidance on the best solution for your roof.

Yes it can, 12 months a year!

You will need an edge or an up-stand to hold the system in place. If you don’t have a parapet edge we can supply roof edge trims. Please get in touch if you need advice about this.

The drainage layer is there to absorb enough water for the plants to grow naturally but also to allow excess water to run off.  This also means that the substrate won’t become waterlogged.

There are 2 types of substrate layer for our green roofs:

  • Roof garden substrate is the growing medium in which the green roof plants grow. A special mixture is available for each type of green roof; extensive or intensive. This specially designed roof garden substrate ensures that each layer of vegetation gets the proper nutrition, despite the limited thickness of the soil layer.

    This substrate is usually for heavier weight systems and where the weight bearing capacity of the roof is known. If you are in the planning stage of your extension or new build, you can employ a Structural Engineer via your Architect to work out the maximum weight your roof can hold. This will then dictate which system you are able to choose.
  • Substrate roll is a lightweight, green roof substrate. It is manufactured from long mineral wool fibres and forms a compact and stable unit. The composition has been designed so that it has excellent water absorption properties.


Application

Substrate roll can serve as a lightweight substitute for roof garden substrate. It is a good growing medium and as such, is ideal for a lightweight substrate layer for an extensive green roof.

Substrate roll is available in various thicknesses. We will be happy to advise you of the best solution for your green roof.

Extensive Green Roofs are thin lightweight roof systems that typically have a planting media measuring 4 to 20 cm deep, with a saturated weight from 45kg/m2 to 150kg/m2 meaning this type of roof can be installed on most roofs.

Intensive Green Roofs are much heavier and thicker as their growing media ranges from 20 cm to 100 cm weighing from 180kg/m2 and up to to 500 kg/m2 saturated;

Semi intensive green roofs, as their name states, are a combination of the other two types. They have a thinner planting media than an intensive roof but thicker than an extensive one, and the whole system ranges from 120 to 250 mm with a saturated weight from 120-200 kg/m2

An Extensive Green Roof offers a number of advantages over an intensive green roof:

  • Lower costs
    The installation and maintenance costs of an Extensive green roof are relatively low compared to Intensive green roofs.
  • Less load on the support structure
    An Intensive Green Roof is many times heavier than an Extensive Green Roof, as it’s comparable to a garden with shrubs and trees, but on your roof. The load for the roof construction is therefore much higher. Intensive roofs can therefore only be constructed on new buildings where the weight of the roof is known.
    Conversely, Extensive roofs can easily be installed on almost any kind of roof; flat or pitched. 
  • Minimal maintenance
    An Extensive green roof requires minimal maintenance. It is enough to fertilise twice a year whereas, an Intensive green roof requires regular maintenance such as pruning and strimming/mowing to keep the plants in good condition, just as you would in an ordinary garden.

Sedum is used because it is drought resistant and very hardy. Under normal circumstances the roof should not need regular watering. However, live material must be irrigated immediately following installation. This irrigation must continue in the first few months following installation and again in especially hot and dry periods. Full saturation of the system is recommended once a week in these periods.

The amount of maintenance required really depends on the type of green roof you have installed.

Sedum roofs require little on-going maintenance, generally twice a year, Spring and Autumn, is enough and a general clearing of gutters, a little weeding along with fertiliser should suffice. See our maintenance page for more information.

Biodiverse & Wildflower roofs do not require any additional watering or feeding as  this could alter the natural balance of plants on your roof. Also, the addition of extra nutrients and water will only encourage excessive growth in the grasses, which will consequently out-compete the more desirable native plants. Only under very dry conditions, is it necessary to irrigate at least 1 hour once a week.

Mowing and strimming will be required with these roof types. See our maintenance page for more information.

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