Roof gardens are built for both their aesthetic and their functional values. A roof garden can provide temperature control, architectural enhancement, hydrological benefits, and of course food. It can also serve as a habitat for wildlife. There are a number of advantages when you plant a roof garden. It can cool the room below it, especially during a hot day. During winter, it provides insulation against the cold. In Germany, roof gardens are required to retain water from evaporating. It will prevent flash floods from occurring. There are three basic types of roof garden. They differ according to the maintenance they require, the type of plants the roof will support and the depth of the soil. The three types of roof gardens are:
Extensive Roof Garden
This is the easiest type of roof garden to maintain because it uses shallow soil. Extensive roof gardens are lightweight, and ideal for the roofs on garages, sheds, and other small extensions of the home. Although it’s easy to maintain this type of roof garden, it has the least aesthetic value, and the number of plants that can grow on it is quite limited. Examples of plants you can grow in an extensive roof garden are lichens and mosses. Lichens are symbiotic organisms that can colonize on surfaces such as glass, metal and plastic. Mosses are small green plants that do not require large quantities of nutrients for survival. They cling on stone and walls and, can live off of rainwater alone.
Semi-extensive Roof Garden
This type of roof garden has deeper soil, and can support a larger variety of plants. It can therefore be decorated more easily than the extensive roof garden. The soil is heavier in a semi-extensive roof garden, and requires a stronger structure in order to support it. One could plant sedums in this type of garden. These are succulents that can store water in their tissues. That means you won’t need to go out and water them every day – but during times of drought, they could die and turn patchy if not properly cared for. On a semi-extensive roof garden, you can also plant wildflowers that can grow without any maintenance.
Intensive Roof Garden
This type of roof garden can support trees and elaborate arrangements. Intensive roof gardens require large, strong structures to support them. Most homes are not suitable for this type of roof garden, but they can be found on concrete buildings and on top of roof decks. There’s no limit to what you can plant in an intensive roof garden, so long as the structure of the building can support the weight.
Another interesting option for green roofing is the use of Vegetation Blankets.