Greenfix extensive green roof for sustainable roof construction
With a Greenfix extensive green roof, you achieve a lightweight and low-maintenance green roof structure for flat and gently sloping roofs. You combine water buffering, additional insulation, and protection of the roofing membrane in a single system that is suitable for both new construction and renovation.
Due to the limited substrate layer and vegetation, you opt for an efficient, low-load solution, ideal for projects where technical simplicity and durability are central.
Technical advice for your green roof
Contact us for support with assembly, sizing, and choosing the right Greenfix system for your roof project.
Construction of an extensive green roof
A Greenfix extensive green roof combines various layers into a high-performance whole:
- vegetation layer with sedum or herbs
- substrate layer with limited thickness and load
- drainage and buffer layer for water management
- protective layer and filter fleece
- integration on existing or new roof structures
Characteristics of an extensive green roof
- water buffering volume: ±50 l/m²
- saturated weight: <150 kg/m²
- total build-up height: ±13 cm
- roof pitch: 1 – 5°
- accessibility: walkable
- maintenance: limited
- vegetation choice: sedum, grass and herbs
Applications and considerations
You apply extensive green roofs to residential and commercial buildings where low maintenance requirements and roof load are important. They contribute to rainwater retention and extend the lifespan of the roof waterproofing.
For green roofs, it is recommended to provide a minimum slope. For a flat roof (0% slope), it is best to use a Greenfix Retain drainage and buffer plate, with a water buffer capacity of up to 20 l/m². For walkable or drivable applications, fill it with 4/20 granules for added stability and drainage.
Build-up of Greenfix extensive green roof
Greenfix sedum mat
A ready-made vegetation layer with coconut mats planted with at least 8 different species of sedum. The choice to instantly enjoy a green view. Thickness: 30 mm.
Greenfix extensive substrate mix
Green roof substrate. Mixture based on lava rock composed of organic and mineral components. Thickness: 60 mm.
Greenfix Retain Eco 20 mm
Perforated dimpled membrane acting as a drainage layer. Equipped with a filter geotextile on top, with an integrated water retention capacity of 6 l/m². Height: 20 mm.
Greenfix Protect
Protective layer made of recycled textile fibers to protect the roofing membrane against mechanical damage. Greenfix Protect also has a leveling function.
Greenfix root barrier film
Optional membrane to be installed if the roof waterproofing is not root-resistant.
FAQ
1. What is the difference between an extensive and intensive green roof?
An extensive green roof has a thin substrate layer and limited vegetation, while an intensive green roof is heavier and more intensively planted.
2. What tax can you expect?
Extensive systems have a relatively low roof load, depending on the structure and water saturation.
3. Is extra drainage needed?
Yes, a correct drainage and buffer layer is essential for water drainage and buffering.
4. Can you install extensive green roofs on existing roofs?
Yes, provided the roof structure has sufficient load-bearing capacity and is prepared correctly.
5. When do you use Greenfix Retain?
For roofs without a slope (0%) or when additional buffering and drainage are needed.
