Rats, for all of their vileness, are very smart creatures. As proven in laboratories, rats are quick to solve problems that prevent them from going where they want to go. That said, you should no be surprised by how rats go from the foundation to the second story of your home. Getting to the second floor of your house is not difficult at all for these creatures. Here is how they usually do it and how you can stop rats from invading your entire home.
To humans insulation is itchy, scratchy, and uncomfortable stuff. To rats, it may affect them physically, but it is still a ladder. They will use the foil- or paper-backed insulation to climb up through the walls and into your bedrooms. One of the best ways to stop rats from using wall insulation as their own personal ladders is to replace rolled wall insulation with blown insulation. Blown insulation gives rats nothing to hold onto, and often causes them to fall down into the fluffy insulation and get stuck. The rats may look for other ways to get upstairs, but replacing the insulation will prevent them from using this way.
What is good for a squirrel or mouse is good for a rat. All trees that overhang your roof are perfect means for rodents to climb the trees and look for a spot to drop down onto the roof. Once on the roof, the rats only have to look for a weak spot where they can wiggle their way into your house. Voila! They are on the second story and all the rats had to do was climb a tree.
The answer here is also a simple one, or two. First cut down the tree or cut off the limbs that extend over the roof. Then place rat traps or bait traps the areas where rats are most likely to try to enter your second story.
Sprinkle Poison Around the Base of Your House
Finally, rats will not attempt to cross a barrier to get into the house if you offer them something in exchange. Put lots of poisoned bait around the foundation. The rats will eat the bait, thinking it's a good food source. Then they will slink away to find other food sources, dying as they go. Now you have managed to stop the rats from entering, stopped them from climbing inside the walls, and stopped them from entering at the roof level.
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