Your lighting looks like it could be an issue, I see a hanging lamp there but there’s no light coming from it, so it could be the illumination is coming from the skylight or something, that should be turning black. But–another issue will be that you’re building flat walls out of multiple parts, which will end up with slight variations in the lightmap, it would be better to model those walls specifically rather than make it out of simple meshes which will avoid the lighting issues and will improve performance by reducing the number of meshes and draw calls.