Green Roof Drainage Options

The design of the different drainage layers allows for a portion of the stormwater to be retained above where the water is allowed to flow freely off of the roof.

Green roof drainage options.

Zurn offers a variety of roof drain solutions suited for modular green roofs such as the z163 and the 84 options both shown below. They are pre assembled drain cores with root resistant filter fabric attached to top layer. The drainage also contributes to good aeration of the plant roots. For flat or nearly flat roofs primary drains are located at the lowest point of the roof.

You should place the anchor elements directly above the drainage layer and filter fabric. Flow of water into them is promoted by positive drainage. Secondary overflow drains are located at a higher point on the roof. Because green roof soil systems like rooflite s rooftop trees soil system are built up from the bottom it s easy to bury steel mesh concrete blocks lawn grid pavers or ballast stones to use as anchors for trunk tie downs or root ball strapping.

Green roof solutions can provide you with everything that you need for a successful green roof installation including. 25mm 1 thickness is standard for thin extensive roofs 40mm 1 5 is recommended for enhanced water storage and drainage on thicker extensive roofs and semi intensive roofs and 60mm 2 5 is available for. Green roof solutions offers many different drainage layer options depending on system goals regarding water retention. A green roof may require a separately plumbed secondary drainage system also known as the overflow relief system.

Oddly enough though this style of green roof isn t a cool roof. When you re thinking about what goes into a green roof the terminology can really get in the way. During a dry period the water stored can be reabsorbed by the vegetation layer above. If stone ballast is being utilized around the drain the 84 option shown above.

The most critical role of the drainage layer is to provide an adequate flow of water off the roof during and after rainfall. Technically speaking the term green roof applies to a roof upon which living plants have been planted and nurtured. Three thicknesses of drainage plates are available to meet the drainage and water storage requirements of almost any green roof. It buffers water and allows excess water to drain away.

They are pre assembled drain cores with root resistant filter fabric attached to top layer. Root barriers filter fabrics multiple drainage options edge restraints inspection chambers green roof media plants and a patented wind erosion control system. The drainage layer has an important role to play in the total system structure of a green roof. Think the hanging gardens of babylon.