This document provides an overview and definitions of green roofs and green walls. It discusses the history and types of green roofs, including extensive green roofs which have thin growing mediums and require low maintenance, and intensive green roofs which are thicker and require permanent irrigation. Extensive green roofs are well-suited to existing buildings, while intensive can function as outdoor gardens but require stronger building structures. Green walls can be real walls containing growing medium or surfaces covered with climbing plants, and are categorized as indoor or outdoor, with outdoor types requiring continuous irrigation.