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Smart systems for green and utility roofs

Why does Nophadrain use a woven geotextile as filter layer?

Wednesday, June 26, 2019

High compressive strength and special woven filter geotextile ensure optimal drainage on drivable roofs.

To prevent unpleasant surprises such as loose or submerged paving, a pressure-stable, long-term drainage system is the essential basis for a stable laying course, sub-base layer or levelling layer. Only then will the desired image of the designer be preserved and is long-term use possible.

The main function of the sub-base layer is to transfer and spread the load, thereby preventing deformation of the paving elements. In addition, it protects the waterproofing membrane against static and dynamic loads. In principle, a sub-base layer is constructively required for load classes 2 and 3 (can be driven on by cars and trucks). Crushed natural material with a granular size of 0/20 and 0/40 are used as sub-base material.

How do you achieve good and sustainable drainage? To be able to fully answer this question, the characteristics of height, compressive strength and filter fabric must receive a lot of attention. The compressive strength ensures that the drainage system retains its shape -and therefore also its height- under the circumstance of heavy load. A strong woven filter geotextile prevents blockage. In this way the complete drainage performance of the system is maintained.

Curious why drainage and compressive strength are so important? Read the article through the link.

Nophadrain offers the ND 600 series Drainage Systems for roofs with a drivable application (and therefore with paving). Besides the extremely high compressive strength of the dimpled sheet (900 to 1,200 kPa), this series of drainage systems is characterized by a special CE-marked mono-filament woven filter geotextile. The woven filter geotextile has a high punch-through resistance, a minimum elongation and a weight of ≥ 280 g / m² to withstand the forces that occur due to static and dynamic loads and to compact the sub-base layer by using a vibration plate during construction and final use. Despite the sharp corners of the foundation material, the foundation layer can be applied directly to this woven filter geotextile without damaging it.

The drainage systems from the ND 600 series are sandwich elements. This means that the product consists of different layers that are connected to each other. To increase ease of installation, these layers are not thermally bonded but glued. As a result, the glued woven filter geotextile, which also has an overlap of approximately 10 cm, can be easily pulled off from the dimpled sheet. In this way it forms the best possible transition in the case of overlaps, roof penetrations or edges.

In summary: the high compressive strength, the special monofilament woven filter geotextile and the adhesion of the layers ensure that the drainage capacity is guaranteed for many years and it makes the installation as effective and efficient as possible. Nophadrain, it can be that easy.