Greening Roofs

Roof surfaces often provide the largest percentage of impervious surface on a site. The impact of this on the surrounding environment is that stormwater is not absorbed where it lands. Stormwater is forced to flow to a few locations where, at an increased volume and speed, it spills onto the land contributing to erosion. Along the way, it carries harmful pollutants from the roof surface.

By holding stormwater where it falls, it can evaporate naturally into the environment and the groundwater table at a slow and steady rate. One way to accomplish this is by greening the roof, which simply means adding grass and plants to the roof surface. A green roof limits the amount of heat emitted into the atmosphere and naturally cleans the rain it absorbs. This approach also acknowledges the principle that the natural ways of cleaning air and water are the best ways.

Green roofs help to protect the roof surface from harmful UV sun rays and severe weather. It acts as a natural insulator, which reduces energy consumption. Stormwater runoff is reduced by 60% compared with conventional roofs. They absorb noise pollution and sunlight rather than reflect them. Green roofs also help to absorb air pollution, enhance biodiversity and provide habitat for birds.

An easy alternative to greening a roof is to add planters on the roof surface. These planters can help block unsightly views and create an inviting space. As with green roofs, they will help to absorb pollution, hold water where it lands, and create habitats for birds.

Plastic pots weigh less and help to retain moisture longer than clay pots. Styrofoam packing peanuts, a non-biodegradable material that would otherwise go to the landfill, make a lightweight drainage material when placed at the bottom of the pots. Put a layer of geotextile material or plastic netting, such as onion bags, between the packing peanuts and the soil to keep the soil from slipping through the drainage material.

Utilize structural soil, which is lighter weight than top soil, in these pots. Add water retention crystals to the potting soil to help retain moisture in the potting soil. A structural engineer should examine the structure before additional weight is added to the roof's surface.

Green parking structures and apartment buildings.
Green parking structures and apartment buildings by incorporating exterior planters into the design. The plants will beautify the building while helping to cleanse the pollution generated from the vehicles.

Build up, not out.
Decrease impervious roof surfaces by building up, not out. Create buildings that are two to six stories high, in keeping with the particular vernacular styling, rather than a series of sprawling one-story structures. Preserve the unused space in its natural form as an open space.