Any openings 1/4″ or larger must be sealed from the foundation to the roofline. They usually live in families of 6 to 8. You must use a poison bait station or trap every 10 feet or more. Also, you must treat adjoining floors above and below. Keep at it until you've gotten them all. You may decide to call an expert in and they will have more efficient treatment methods that will be potentially less harmful to children or pets.
Contact Pestmasters at 285-1191