The first step in rodent proofing is figuring out where the little pests are getting in at. When it comes to rodents they can squeeze in through the smallest openings. If their head can fit through a hole their whole body will.
This makes it very important for us to find every hole. Even the ones that are only the size of a dime. In some cases this will require removing and replacing the old insulation. Often times rodents will find holes under the insulation and burrow through the insulation.