Concrete carbonation is a key process driving long-term CO2 uptake in the built environment. However, for internal surfaces the rate of uptake can vary depending on the location and exposure condition of the concrete surfaces. In residential buildings, floor coverings such as tiles or carpets may act as physical barriers that reduce CO2 diffusion and limit carbonation depth, with the potential effect not well captured in current life cycle assessment practices. This study investigates the influence of coverings on carbonation in concrete floors for both low-rise and mid to high-rise residential buildings over a lifetime of 50 years. A numerical simulation approach was applied using established carbonation models. Surface conditions considered include bare concrete, tiled surfaces, and carpeted floors. The research seeks to improve the accuracy of CO2 uptake estimates in residential buildings by clarifying the role of floor finishes in carbonation modelling. The results showed that in the low-rise structures external walls dominated and the impact of coverings was minor (3%). In mid-to-high-rise structures slabs dominated uptake, with the reduction of approximately 12%.