− | The manufacturer should be consulted for the design specifications of their product. In pervious concrete and porous asphalt systems, the concrete or asphalt mix specifications and construction procedure are key to proper functioning. These systems require well trained and experienced contractors for installation. | + | The manufacturer should be consulted for the design specifications of their product. In pervious concrete and porous asphalt systems, the concrete or asphalt mix specifications and construction procedure are key to proper functioning. These systems require well trained and experienced contractors for installation.<br> |