Green Roof Water Retention

Such an extensive green roof will have a water retention capacity up to 44 l m and a surface weight in water saturated condition about 130 kg m.

Green roof water retention.

Water retention is really important in case of pitched roofs because their drying trend is more pronounced. Manufacturers whose materials we use for landscape works are well known all over the world. Drainage green roof solutions offers many different drainage layer options depending on system goals regarding water retention. This type of water roof is called a water roof for rainwater retention.

We already had some common projects and results were reliable and spectacular. Traditional soil is heavy and packs tight after repeated rains reducing water retention and aeration for plant roots. Later the sun comes out and the plants use the rainwater to evapotranspire. The water only remains on the roof for a short period of time after rainfall.

The water needs to be drained off to create sufficient storage capacity in time for the next rainfall. Green roof growing medium is composed of mineral aggregates and only a small amount of organic material. The purple roof is the only concept that has been exposed to real life assembled testing in a professional setting. Evapotranspiration et plays a major role in the retention performance of green roofs due to removal of stored water and the corresponding increase in volume available for storage in the green roof medium for subsequent precipitation events.

The most critical role of the drainage layer is to provide an adequate flow of water off the roof during and after rainfall. However a purple roof retains more water than any other green roof concept. Green roofs typically provide stormwater retention as they capture water preventing water from draining and then allow the water to evaporate only through evapotranspiraton processes. Rain falls onto a relatively dry green roof and the green roof absorbs the water usually in pore spaces.

Yes every green roof absorbs and buffers water. When the depth of water stored in the green roof growing media was treated as a variable roof storage was varied from 0 25 to 3 0 inches of storage using the 28 years of state college s daily rainfall data the results see figure 3 showed that the 3 5 inch green roof with 1 6 inches of water storage with a drainage layer and plants was an excellent choice. The rainwater is drained off at a delayed pace using a narrower lower situated opening. It should have good consistent drainage and aeration with a structure that enables it to hold water.