Estimation of construction and demolition waste in building energy efficiency retrofitting works of the vertical envelope

In recent years many research works have been developed to determine the amount of waste generated in building construction sites, but are mainly focused on new residential constructions. However, few studies were found quantifying construction and demolition waste (CDW) in building renovation/retrofitting projects. Current CDW ratios (amount of CDW per refurbished m(2)) for building refurbishment projects cover a wide range of values due to the great variety of techniques that can be used in building rehabilitation projects and that will definitely influence the amount of CDW generated. Therefore, further waste quantification studies, analyzing different types of building rehabilitation projects, are needed as with the current data is not possible to make exact predictions of CDW generation. In this sense, this paper presents the results of a research project analyzing, specifically, the waste generated in building refurbishment and/or retrofitting works to improve the energy efficiency of a building. For this, the seven most common works conducted in the vertical envelope to improve energy efficiency of the building were identified and CDW generation was quantified. CDW generation ratios were stablished for each work using theoretical methods. Further, two pilot construction sites-implementing an External Thermal Insulation Composite System (ETICS) solution- were selected and CDW generation ratios were obtained using experimental data. Results show that the highest amount of CDW generation arises when preparing the vertical surface to be refurbished. Specifically, CDW generated during an ETICS work lies between 2.46 and 65.24 kg/m(2) and 0.012-0.008 m(3)/m(2), depending on whether the insulation layer is applied without removing the existing external coating or after its removal. Moreover, it was found that concrete, ceramic, metal and timber waste are the main waste flows generated and thus they should be further controlled onsite in order to achieve their minimization, recycling and recovery. (C) 2017 Elsevier Ltd. All rights reserved.