This paper presents a comparative study of greenhouse gas emissions due to different wall compositions in accordance with their lifespans. The assessments carried out take into consideration the construction, maintenance and end of life of the walls, for a specific tropical climate site. The energy spent for heating and cooling during the utilization phase of the building was made equivalent for all calculations, in order to isolate the study on the evaluation of the performance of each technical solution. Initially, the methodology is described by choosing technical solutions to the building envelope, determining the corresponding service life for each solution and finding the corresponding GHG index from an appropriate database. Then, the evolution of this indicator is calculated within a given time for the four different technical solutions: Concrete Block; Solid Clay Brick; Cellular Concrete Block; Multicell Clay Brick. Brazilian national standard materials lifespans were adopted. A building lifespan of 150 years was considered. The results of this analysis suggest and quantify the important impact of the lifespans of both the materials and the building itself on greenhouse gas emission indicators. The numerical results presented point out the need to revisit the current life cycle analysis practices. (C) 2014 Elsevier B.V. All rights reserved.