It is rare for chipmunks to enter homes but it can happen. Chipmunks, like rats and mice, can enter your house wherever there is an opening in doorways and foundations. If you have seen a chipmunk in your home or have chipmunks in the yard, you will need to locate and seal any areas where chipmunks can find an entry.
Open doors are an invitation for chipmunks or any other creature to enter your home. Keep doors closed. If the door is shorter than the door frame, use wood to raise the bottom of the door frame even with the door or use a bottom door guard that attaches to the door to extend short doors to fit door frames.
Use screen on doors that remain open for long periods during the day or night. As with the main door, use a door that fits the frame or use a bottom door extender to block access to the home. Keep screens and glass in good repair so chipmunks cannot enter through ripped or missing screens or glass.
Shear cracks in the foundation will allow chipmunks to enter into basements or into the walls of a home, depending on where the cracks appear. Chipmunks may enter in search of food. Use cement or sealant to fill in the cracks and prevent entry. For holes channeling coaxial cable, use rubber stoppers to seal the holes around the cable.
Crawl spaces that have a dirt floor will allow burrowing chipmunks into the crawl space. Chipmunks can make burrows underground 10 to 30 feet deep. If the chipmunk happens to burrow into the crawl space and upwards to find an exit, it will get into the home. The only way to remedy this problem is to install thin screening over the dirt or over the opening of the crawl space so the chipmunks cannot enter the basement.