It is important to ensure that batt insulation does not come into contact with any concrete as it can draw moisture from it. When insulating wall cavities in front of concrete, make sure an approved moisture barrier is in place or an air space is present. If a membrane or rigid foam board moisture barrier is being used, there is no need to leave an air space. If no membrane is present and the studs have been stepped off to provide an air space, ensure the air space does not exceed ¾". Batts must also be installed snug to ensure they do not fall out and end up against the concrete after the drywall is installed.