An attributional, process-based, comparative Life Cycle Assessment has been developed to quantify and compare the environmental performances of a detached house, located in a seismic area of the Southern Italy, designed following two different approaches for its structural components: by using Cold Formed Steel (CFS), with sheathing and insulating panels, or a more conventional reinforced concrete, with brick walls. Both the houses have been designed to minimise energy consumptions. The analysis has been carried out along the whole building life cycle, broken down into three main phases: pre-use, use and end-of-life. The study quantifies the environmental impacts related to each of these phases, based on high quality data, which have been in large part collected on the field. The results show that the contributions of pre-use and use phases to the overall environmental performances are significant for both the design solutions. The outcomes of the life cycle impact assessment indicate that the house made of CFS has a better performance for the more important environmental impact categories, namely Respiratory Inorganics, Global Warming and Non-Renewable Energy. These advantages increase further, up to 24%, if the possibility of an easy and total disassembly of the CFS structure is taken into account, with the related recovery of great part of the CFS members as well as sheathing and insulating panels. This aspect, together with the good answer to seismic events and the lower capital costs, make the CFS solution particularly appealing for a detached house, in the considered residential area.