Yes, the Rodent Stop can be used on the exterior of a building along any crack that may be providing access to insects or rodents that you need to seal up. Ideally do this on a dry day.
We are unsure of the specific coverage provided per tube of RodentStop, but you may contact the manufacturer directly with questions at (610) 849-1723, or via their website's contact page here.
RodentStop is gray.