Green Roof, ExtruPol and ExtruBit — Newell Roofing Products

Green Roof, ExtruPol and ExtruBit - Newell Roofing Products

February 15, 2013 by amullins

Covering roofs with greenery is cost-effective

Green roofs as an element of architecture attract attention and bring districts closer to nature. Moreover, they are an optimal sealing protection and contribute to longer performance of roofs, which increases the value of a building. With the help of ExtruBit and ExtruPol you create a basis for durable, precise and economical sealing by covering a roof with greenery.

Types of Green Roofs

Extensive green roofs

Self sufficient plants with the lowest vegetation requirements

Simple intensive green roofs

Simple intensive green roofs are entirely covered with grass, perennial plants and tree plants. They usually require minimum maintenance.

Intensive green roofs

Luxury roof gardens, green areas in front of the windows of schools, hospitals, offices or hotels.

Drainage of a Green Roof

The primary function of a roof is to provide a watertight covering to ensure free flowing drainage to gutter or outlet locations.

Typically a green roof will intercept at least the first 5mm of rain in any shower, reducing run off to sewers and it is for this reason there is a growing appreciation of the benefits that green roof can bring in reducing rainwater run-off by playing a key role in sustainable urban drainage systems.

Green roofs also help to reduce the effect that makes cities hotter than the surrounding countryside. To gain the best benefits the building should be entirely enveloped in vegetation, with both green walls and a green roof, this helps to keep the building cool in summer, and offer protection that makes the roof membrane last longer.

Weight of a Green Roof on Rest of The Structure

Depth of substrate used determines the weight of a green roof. It is vital to check that the roof structure can support the maximum weight of the green roof when fully saturated. It is also important to consider when a roof is almost entirely desiccated during an extended dry spell, the minimum weight per m 2  is vital for wind uplift calculation purposes. It is essential to ensure that the roof build up can resist the maximum uplift to be subjected.

The minimum dry weight depends on many factors, the location, the height and the geometry of the roof. A low level roof in the middle of a city centre doesn’t need as much resistance to wind uplift compared to a high rise coastal installation.

Installation is simpler and there is no need for penetrations when you opt for a lightweight modular solution. A typical modular green roof comprises two elements:

Green Roof, ExtruPol and ExtruBit - Newell Roofing Products
  1. A fleece layer which is rolled out
  2. The pre-grown and pre-established planting, grown within the cuspated layer and simply placed upon it.

Pre-grown and established plants such as sedum or sedum mix with wild flowers and grasses are much less susceptible to initial wind uplift and need no watering in situ.

Fitting a Green Roof

The integrity of the waterproofing is the key issue any green roof, after all it must perform its most important function of keeping water out. ExtruPol and ExtruBit satisfies the higher requirement of the FLL Standard for green roofs offering resistance to both roots and rhizomes. If roots or rhizomes should penetrate the waterproofing layer integrity will be lost and the roof will leak and so having resistance is essential.

Installing a modular green roof system can be delayed until following trades have been completed. Prior to the installation of the pre-established modular trays the integrity of the waterproofing can be tested.

Structure of a Green Roof

The requirement of permanently leakproof roof is met

Roofing and sealing membranes of SCHEDETAL meet and exceed the requirements of DIN and EN standards, i.e. the requirements of a European association registered under the name: ddDach, which may be translated as permanently leakproof roof.

Increasing the Value of Property

Planting greenery on roofs is cost-effective: You increase the residential and relaxation value of a building, maintain the value of property leading to main-tenance and operation costs reduction. Small wonders 11 million square meters of flat roofs are greened in Germany every year. The costs of roof greening pays for itself within several years!

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