Author(s)

A. Teemusk & Ü. Mander

Abstract

Greenroofs are new technology that can be applied in areas such as present-day cities, where less and less green space is available. Greenroofs have many benefits: they make buildings more thermally efficient, prolong the life of a roof, ameliorate extremes of temperature and humidity, reduce surface water runoff, help to reduce the urban heat island effect, air pollution and noise, and provide green space for people and wildlife. Greenroofs have been studied in many countries, from the point of view of thermal performance, protection of the roof membrane, stormwater retention and runoff quality. Although the results are sitespecific, it is necessary to review these studies. Greenroofs were found to be effective in helping to keep buildings cool in summer and also to reduce building energy consumption. Research showed that planted roofs reduce the temperature fluctuation in the roof membrane. Greenroofs delay rainfall runoff and reduce runoff rate and volume. The results of greenroof runoff water quality showed that they behave as a sink or as source of contaminants in runoff water. The results of the investigation of Light Weight Aggregates (LWA)-based greenroofs in Estonia showed that an extensive greenroof is sufficiently capable of protecting the layers of the base roof from extreme temperatures. Typically, light rain is retained, whereas heavy rain penetrates the greenroof media. The quality of the runoff water varies depending on runoff character and the pollutants accumulated on the roof. Keywords: energy saving, evapotranspiration, greenroof, rooftop garden, runoff quality, thermal performance, water retention. 1 Introduction The main objective of this study is to give a sufficient review of the results of research that has been performed to find out how greenroofs work in reality. We also present the results of the first research into greenroofs in Estonia.

Keywords

energy saving, evapotranspiration, greenroof, rooftop garden, runoff quality, thermal performance, water retention.