Do you have lots of windows shining daylight into the basement? Are you sure about the fire marshall's laws for legal exits? Do you really want to be in the basement all day with your daycare children? Just some things that crossed my mind since my daycare is on my main floor and I've taken all these things into consideration. I like the fact that when I'm preparing breakfast/lunch/afternoon snack that the children are in my line of sight in my living room.