Having any kind of animal living under your house is less than restful. On top of the noise and mess factors, there is a small risk the animals may cause structural damage. Ground squirrels, a group that includes chipmunks and prairie dogs, are among the animals quite likely to burrow under a house. They are naturally tunnelling animals and often lose some fear of humans in residential areas. The only real way to stop ground squirrels' burrowing is to construct a physical barrier. Repellents are only a short-term solution and won't stop particularly determined squirrels from deciding your house is ideal to nest under.
Dig a trench 1 foot wide and at least 1 foot deep around the outside of your house. A deeper trench may be needed because chipmunks, for instance may burrow 2 or 3 feet down.
Bend the wire mesh into the trench so that it runs down the side of the trench next to the house and then across the bottom in an L shape. Larger sizes of wire mesh will keep out squirrels but one advantage of using a 1-inch or ½-inch size is that it also keeps out smaller rodents such as mice, voles and rats.
Fill the trench in and tread the soil down firmly.
Remove grass and weeds as they grow back over the trench to make the border around your house less appealing to squirrels. Paving or gravel makes a permanent, squirrel-unfriendly border.