Rats can fit through holes as small as half an inch in diameter—about the size of a quarter. This capability allows rats to enter basements, attics, and other hidden areas of your home, often using foundation cracks, gaps around pipes, and damaged vents as entry points.
During the day, when rats are usually hidden inside, you can block the hole entrance. If there are occupants during the night, they will dig their way out past the obstruction. Come in the morning, and you will find out for sure if something is living there.
Rats, like mice, can squeeze through impossibly small gaps (anything down to the size of a 10p coin) and should never be underestimated as to their versatility and persistence when trying to enter a building.
To prevent rats from climbing wire mesh, it's important to use a mesh with a small enough opening to prevent them from passing through. A mesh with an opening of 6mm (1/4 inch) or smaller is typically recommended for rat control.
Peppermint oil — Essential plant oils like peppermint, rosemary, citronella, sage and lavender have strong botanical scents that rats dislike. One customer successfully repelled a rat by stuffing a peppermint oil soaked tissue into the rat hole chewed into the wall. The rat appeared to never come back.
Hardware cloth (wire mesh): 19 gauge, 1/2 x 1/2-inch mesh to exclude rats; 24 gauge, 1/4 x 1/4-inch mesh to exclude mice. Aluminum: 22 gauge for frames and flashing; 20 gauge for kick plates; 18 gauge for guards. Second, install a gnaw-resistant barrier (Table I), over the gap to prevent entry (Figure 4).
The two best ways to remove rats are traps or poison. The use of either requires caution!
In most cases, a raccoon needs only four inches to squeeze through — think roughly the diameter of a small piece of fruit. Many property owners believe they should spot a hole that size, especially if it is around their attic or garage, but raccoons are intelligent and capable animals.
It's crucial to stay far away from the rats and not touch them. Rats can carry a variety of diseases that are dangerous to humans and pets, so it's important to avoid rats.
Close and Fill
Once the burrow is flushed, seal the entrances to stop rats from returning: Inactive burrows: Fill the hole with dirt, then stomp or tamp it down with a shovel to compact the soil. Check back in a few days to see if rats have re-excavated the burrow, which would indicate it is still active.
A small infestation can grow into a large colony quickly if not adequately dealt with. Once rats have established a nest, they will often return even if it has been disturbed. They choose their homes wisely, and once they have taken the trouble to set them up, they will usually stay put.
A rat burrow can be anywhere from one to six feet deep and will have an entrance, an exit, and maybe even an escape hole. A typical burrow will house a family of approximately eight rats.
Ammonia is another great tool to use: mixing a cocktail of two spoons of detergent, some water, and two cups of ammonia. A bowl of this mixture should be placed in trouble areas since rats hate the smell of it. Other smells rodents hate to include castor and peppermint oil.
Steel is about the only thing rats cannot chew through. In addition to chewing through chicken wire they can chew through wood, cinder blocks, and plastic.
Under optimal conditions, an adult rat typically requires a horizontal gap of approximately 12mm (about half an inch) and a round hole with a diameter of around 25mm (about one inch) to pass through comfortably.
A rat burrow typically appears as a small hole in the ground, ranging from 2 to 4 inches in diameter. They have smooth walls inside and hard-packed dirt around the entrance. The loose dirt is often kicked out during the digging process which forms a fan-shaped pile around the hole.
Snap traps can help make things easier since they kill rats quickly and keep the body in a place where you can easily collect and dispose of it.
Outdoors, rats face a variety of predators. In these environments, large birds of prey — including hawks, falcons and owls — feed regularly on rodents. Owls are particularly formidable predators, as their nocturnal behavior ensures that they are most active when rats go out in search of food.
Smooth surfaces: Rats cannot climb smooth surfaces such as glass, metal, and polished wood. This is because they need something to grip onto with their claws. Vertical surfaces without ledges: Rats cannot climb vertical surfaces that do not have any ledges or other handholds.
Four Things Rats Cannot Chew Through
Any materials with greater strength than their incisors are too difficult for them to chew on or through. Examples of hard materials include: Steel, like sinks, ovens, refrigerators, steel beams, steel wiring in ductwork, and fencing. Iron to reinforce concrete and other structures.
Seal any holes you find to stop rodents from entering. Fill small holes with steel wool. Put caulk around the steel wool to keep it in place or use spray foam. Use lath screen or metal, cement, hardware cloth, or metal sheeting to fix larger holes.