Despite what you may have heard, bats do not chew through wood, walls, or other building materials like mice or other rodents do. However, they have been known to squeeze in through tiny cracks or crevices or kick out some insulation as they enter and exit walls or attics.
If you are worried about a bat getting in through your walls there are many types of building materials that you can purchase to try and keep them out. Mesh, caulking, screening, etc. work great for this. However, it is very important that individuals not close off openings during a bat’s mating season (June-August) as baby bats are not born able to fly and you could trap them inside to die or starve to death if they are unable to get out or their mother is unable to get back in. Some baby bats take weeks to learn how to fly. It is best to wait and bat proof your home after maternity season.