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Smart systems for green and utility roofs

Curious why high compressive strength and great drainage are important for parking decks?

Tuesday, June 18, 2019

Not only vegetation, but also pavings and system build-ups can suffer from too much water.

Water is of vital importance for vegetation. But as so often in life, too much of a good thing can also be harmful to vegetation. Therefore, a sustainable drainage that is perfectly adapted to the green roof system is essential for a healthy, long-lasting and, visually appealing vegetation.

This approach is not only true for plants, it also has a high priority for system build-ups, in which coverings such as plates, paving, etc. are used for trafficable or walkable areas on roof structures.

With the optimal choice of the drainage system as the core of the entire system structure, it is possible to prevent the covering from sinking when the laying course or the sub-base layer is saturated with water, and that build-up water in winter leads to frost damage. In addition, due to the hydrostatic pressure on the waterproofing membrane leaks may occur.

It can be concluded that good and sustainable drainage is important for roofs with paving. But how is good drainage being achieved? Nophadrain offers the ND 600 series of drainage systems for roofs with a drivable application. This series of drainage systems is characterized by a dimpled sheet with an extremely high compressive strength (900 to 1,200 kPa) and a special monofilament woven filter geotextile. The products from the ND 600 series are sandwich elements: the drainage systems consist of different layers that are glued together (e.g. ND 620hd Drainage System). The drainage system provides free space under the understructure of the drivable surface in order to drain the water without pressure.

What makes compressive strength so important?

There are high loads present during both construction and the end use of the paving on the roof. It is not only the weight of the composition that counts, but also the dynamic load and point load caused by cars and heavy goods vehicles play an important role.

The higher the build-up, the better the pressure is distributed and the lower the point load becomes. The higher the structure, the heavier the static load on the roof construction due to additional materials. The roof constructions must be calculated in advance for this. Because the compressive strength of the ND 600 series Drainage Systems is so high, it is still possible to carry a large load with a relatively low structure. Moreover, the build-up height of these drainage systems is only 12 and 13 mm. This means less plastic on the roof.

Not only is it possible for the ND 600 series Drainage Systems as part of the roof structure to be accessed by cars and trucks during end use. During installation of the utility roof it can also be accessed with a vibrating plate to enable a stable laying course or sub-base layer.

The high compressive strength of the ND 600 series Drainage Systems ensure that the dimples of the drainage system remain intact, despite high loads. In this way good and sustainable drainage is guaranteed. The filter fabric of the ND 600 series is at least as important as the high compressive strength. The combination of both makes this series twice as strong. Wondering why this fabric is so special? You can read more about it next week.