Water Retention For Traditional Roof Vs Green Roof

However retention is not always effective as it fills up the entire empty storage space in green roofs and then takes time to dry out and make room for new.

Water retention for traditional roof vs green roof.

Retention works like this. Manufacturers whose materials we use for landscape works are well known all over the world. Looking great energy efficient and environmentally friendly too green roofs better utilise an often neglected area. Yes every green roof absorbs and buffers water.

Traditional soil is heavy and packs tight after repeated rains reducing water retention and aeration for plant roots. The secret of green roof water retention is green. Rain falls onto a relatively dry green roof and the green roof absorbs the water usually in pore spaces later the sun comes out and the plants use the rainwater to evapotranspire. For water retention performance we monitored runoff from four full scale green roofs including one built up system one modular tray system and two vegetated mat systems.

Green roofs are covered with plants and vegetation bringing a number of excellent benefits to every building. We already had some common projects and results were reliable and spectacular. This is particularly beneficial on sites where land take. Drainage and water retention elements with low medium or high retention capacity are components of the green roof system.

Abg blueroof offers a new development in the management of storm water by collecting and retaining rain fall within the actual roof structure before discharging at a defined controlled rate. Blue roofs are designed to attenuate rainwater rather than drain it away as quickly as possible as in traditional roof drainage design. However a purple roof retains more water than any other green roof concept. Data collected from a study by researchers at the pennsylvania state university center for green roof research show that green roofs captured up to 80 of rainfall during rainstorms compared to 24 typical for standard roofs.

The trends between the guidelines and the simulations are similar although the absolute. Green roof growing medium is composed of mineral aggregates and only a small amount of organic material. In the german guidelines for green roof construction yearly values of green roof retention start at 40 and increase roughly 1 per 10 mm substrate thickness resulting in 70 retention at 250 mm after which it remains at 70 for layers up to 500 mm. 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.

The purple roof is the only concept that has been exposed to real life assembled testing in a professional setting. We gathered roof runoff data for over 100 storm events for each green roof over a period of 23 months. As green roof plants mature and root systems grow storm water retention may increase.