If the room is habitable, heated and/or cooled, the basement is considered a finished room. It doesn't have to be 'pretty'. A finished basement doesn't necessarily add value to a home. That depends on variable such as the neighborhood, what the layout of the rest of the house is, and its use. (Bedroom vs. Family Room vs. Wood Shop vs. whatever.)
My best to ya and hope this helps.
Jay J -Moderator
PS: You can ask the Appraiser this same ? ...
PPS: God Bless America!