You can't make your property completely snake-proof if you live near woods, creeks, or undeveloped land in WNC. And honestly, snakes passing through your yard isn't a problem. They eat rodents, and that's a service you're getting for free.
But you can make your home a lot less attractive to snakes. And the approach is the same one that works for almost every wildlife issue: remove shelter, remove food sources, and seal entry points.
Remove ground-level shelter. Woodpiles, scrap metal, boards, dense ground cover, and landscape debris all give snakes a place to hide. Move firewood away from the foundation. Keep vegetation trimmed close to the house.
Address rodent problems. If mice or rats are getting into your home, snakes will follow. The rodents leave scent trails that snakes track like a highway. Solving the rodent problem is the most effective thing you can do to prevent snakes.
Seal entry points. This is the big one. Every gap wider than a quarter-inch is a potential entry point. Crawl space vents, foundation cracks, utility penetrations, roofline gaps, and garage door seals are the most common problem areas in WNC homes.
Trim trees and shrubs away from the house. Black rat snakes are strong climbers. If branches touch or overhang your roof, that's a bridge to your attic. Keep a clear gap between vegetation and the roofline.