Green roofs
We build green roofs from A to Z
What to consider before building a green roof?
Clarify these basic points:
What style do you like
How much do you want to invest
Possible load on the roof structure
Our services
Send us the drawing of the roof, the location and your idea. We will prepare an offer for you. We believe that together we will find a solution that will satisfy you not only aesthetically, but also financially.
We adhere to Green roofs standards.
We can build the whole roof composition
We guarantee you the whole roof
Green roof composition
- ✓ Plants
- ✓ Substrate
- ✓ Filter layer
- ✓ Drainage + hydroaccumulation layer
- ✓ Protection layer
- ✓ Waterproofing membrane resistant to root penetration
"We are not made of sugar. We work as is necessary."
IN WINTER
AT NIGHT
IN RAIN
Types of green roofs
Green roofs store water naturally, absorb dust and barely heat up even in extreme temperatures. They protect the roof insulation even better than a gravel embankment and they extend its life. Thanks to reduced charges for drainage of rainwater, it is possible to save money in many cities that have charges divided into water and sewage. Urban plans increasingly support or at least acknowledge greening of roofs as a compensation measure. This creates valuable biotopes.
With each green roof, a new living space is created. Intensive greening with areas of grass and plants, areas for paths and rest can be created and used as a garden. On the other hand, extensive greening is created with plants that are not demanding and mainly low-growing, and are meant to be walkable only for control and care. Both forms of greening create valuable and interesting alternative biotopes for plants and microorganisms. They return something to nature from what was lost due to the construction.
By type of vegetation: extensive, intensive
Extensive green roofs
The goal of extensive greening is a naturally based vegetation with low load on the area and minimal care. The plants used to create the vegetation are often sedums. It is also supplemented with drought-resistant herbs. Extensive greening requires minimal care. In the first year or two, before the plants cover the whole surface of the roof, it is necessary to occasionally remove any invasive weeds. Sometimes also to fertilize with slow-dissolving fertilizer, depending on the type of substrate used. Sometimes it is necessary to supplement dead plants after winter etc.
Intensive green roofs
Intensive greening provides a wide range of possibilities for creating and using it as a garden on the roof. It is possible to create recreational areas and plant trees. With proper dimensioning of the vegetation support layer, proper watering and fertilization, the conditions for growth of plants on the roof are almost as good as in the ground. It is necessary to pay attention, for example, to the stability of trees and possible negative effects of the building, such as sunlit facades. The design of intensive greening and especially the selection of plants according to the object requires appropriate professional knowledge. For dimensioning the greening support layer, simple formulas can be used, namely „height of growth/10 = thickness of the substrate layer“. Grass and soil-covering plants need at least 20 cm of substrate. Even with large water storage capacity of substrates, intensive greening and especially grass must be regularly watered during the dry period. As with any garden near a home, there is also a direct relationship between the condition of the vegetation and the care for it.
By load: light, medium, heavy
Statics - load of the roof structure
The load of the roof structure is one of the key criteria for greening. For intensive greening, at least 300 kg/m² of surface load should be calculated according to the proposed substrate thickness. For extensive greening, the load is about 150 kg/m² in the saturated state of water. This applies to the use of substrates. Today, mineral mats can also be used, which significantly reduces the load to about 50 kg/m². To this load, always add the snow load for the given location.
By slope: mild slope, sloping roofs, steep roofs
Slope of the roof
It can be said that today it is possible to green any slope of the roof. Of course, the greater the slope, the more complex and expensive the solution. Slopes up to 15° are usually not necessary to secure against landslides. For larger slopes, it is necessary to secure the substrate against sliding. The greater the slope, the more fixing elements must be used. This must be solved individually for each roof. Fixing is generally performed either using the lower edge of the roof, fixing over the ridge of the roof, fixing in the roof area, or a combination of these types.
By price: economical, other
Financial cost
The total cost of the green roof is always set individually for the specific roof. For extensive roofs with a slope of up to 15° and the most common composition, the costs are around these values:
- Whole composition without waterproofing membrane: 1100 Kč/m²
- Laying of waterproofing membrane including cladding: 600 Kč/m²
- Laying of drainage and hydroaccumulation layer: 250 Kč/m²
- Laying of filter and protective textile: 125 Kč/m²
- Substrate and its placement on the roof: 350 Kč/m²
Prices are shown without VAT. The price does not include transport to the construction site.
Planting of plants is calculated at 25 sedum seedlings/m². A cheaper variant is the use of seeds, or cuttings. The significantly more expensive variant is the seedling carpet.
There is also a simpler one-layer composition with the omission of the drainage layer.
If there is already a waterproofing membrane on the roof, but it is not resistant to penetration, it is possible to lay a special thin membrane against penetration on it, which does not need to be welded.
We use standard PVC welded film as a waterproofing membrane, occasionally EPDM film or asphalt strips.
Maintenance of green roofs
Roof slope
Extensive green roofs are also often called maintenance-free. This is true only to a certain extent. Once the plants cover the whole roof, it is not necessary to care too much about the roof. However, if we want the roof to also look nice, it is good to go up on the roof at least once a year to pull out weeds, fill in places that have become bare, add slowly dissolving fertilizer, check and clean the gutters if necessary.
Intensive green roofs are just as demanding as with a garden or a park. It depends again on how we want the roof to look.
We have our own plantation
Grants for green roofs
Since January 2017, it is possible to apply for a grant for the implementation of a green roof, with which we will gladly help you.
The grant amounts to 700-1000 Kč/m² of a green roof and you can find more at Nová zelená úsporám. The price of a green roof therefore does not have to be high.
