Lime (CaO) is an essential raw material in masonry and is used in components such as Autoclaved Aerated Concrete (AAC), Calcium Silicate Units (CSU), mortars, renders and plasters. Buildings erected with lime mortars develop mechanical strength and high resilience to movement thanks to the calcium carbonate (CaCO3) phases formed by the reaction of lime with atmospheric CO2. The carbon footprint of these materials is low, as the carbonation process sequesters a major part of the CO2 emitted during the lime production. Lime is produced by the calcination and consequent decomposition of limestone (CaCO3) releasing CO2. The CO2 footprint of the lime production is thus significant and considered “hard-to-abate”; two thirds of the total CO2 emitted is related to the decarbonation of limestone during the calcination process, while one third is due to the fuel required for this latter process (status 2019) [1]. However, the concentrated and controlled release of carbon dioxide during the lime calcination allows for efficient emission management via Carbon Capture and Utilization (CCU) and Carbon Capture and Storage (CCS) processes. Reducing the CO2 from energy, capturing and transforming the CO2 released during the production process, combined with the high amount of CO2 sequestered by lime in building materials allows the masonry to become carbon negative, and thus to be considered as a carbon sponge. This paper addresses Lhoist’s transformation pathway to the production of low carbon lime, as well as the effort to adapt the new lime grades to modern building materials and techniques.