Drying and evaporation in porous media is relevant for many engineering processes and for soil cultivation. These processes occur over several scales, where the evolving liquid-gas interface is important to describe the evaporation at the pore scale, while its effect lies on the REV scale. Our goal is to provide a better mathematical description of REV-scale evaporation by starting with a pore-scale description of the relevant processes and using upscaling to derive an effective model at REV scale. The effect of the evolving interface is explicitly taken into account and different approaches to describe the evolving interface at the pore scale will be investigated.