Exterior improvements such as driveways, parking lots, walkways, playgrounds, and landscaped spaces constitute a large portion of the built environment. Reducing the material resources, water, fertilizers, pesticides, and energy that go into building and maintaining exterior spaces is an important consideration for green design.
Pavement and Pavers
There are many options for creating load bearing and durable surfaces. GreenSpec lists paving products made with recycled content, such as asphalt made with recycled tires, cement pavers made with fly ash, and plastic pavers from recycled plastic. Salvaged bricks and stone pavers made from repurposed granite scrap are also listed.
Pavement is important for both pedestrian and vehicle traffic, but paving large areas can have significant impacts on hydrology, as rain falling on non-porous pavement quickly becomes runoff, or stormwater. This runoff contaminates surface water with heavy metals and other pollutants picked up from pavement. In older cities with combined storm and sewer systems, it can also cause the discharge of untreated sewage. Porous paving options listed in GreenSpec address these issues by allowing water to infiltrate. Pollutants are filtered out of infiltrating water as it makes its way to the water table; and water is kept onsite, which can reduce irrigation demands and recharge local aquifers.
Plastic and Rubber Features
Plastic and rubber features in outdoor environments include parking bumpers, speed bumps, playground and athletic surfaces, tactile warning surfaces, and fencing. GreenSpec lists products that utilize recycled content in place of virgin materials while maintaining or increasing durability.
Regionally appropriate landscape design can reduce or eliminate the need for irrigation, toxic pesticide applications, fertilizer use, and maintenance such as mowing, without compromising the usefulness and beauty of landscaped areas. GreenSpec lists landscaping products that conserve water, such as efficient irrigation systems, native plants and seeds, and hydro-mulching products that encourage germination without irrigation. Other landscape equipment listed is made from recycled plastics and rubber, such as edging material, landscape timbers, and tree grates and guards.